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Uni\ Mfc Internationa] 300 N. ZEEB ROAD. ANN ARBOR. Ml 48106 18 BEDFORD ROW. LONDON WC1R 4EJ, ENGLAND 8107313

D a r r o w , D o n a l d R ic h a r d

THE RELATIVE EFFECTIVENESS OF AN ADVANCE ORGANIZER ON THE MEANINGFUL VERBAL LEARNING AND RETENTION OF JUNIOR HIGH SCHOOL STUDENTS IN INDUSTRIAL ARTS

The Ohio State University PH.D. 1980

University Microfilms International 300 N. Zeeb Road, Ann Arbor, MI 48106 THE RELATIVE EFFECTIVENESS OF AN ADVANCE ORGANIZER

ON THE MEANINGFUL VERBAL LEARNING AND RETENTION

OF JUNIOR HIGH SCHOOL STUDENTS IN INDUSTRIAL ARTS

DISSERTATION

Presented In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University

By

Donald Richard Darrow, B.A., M.A.

*****

The Ohio State University

1980

Reading Committee Approved By

Dr. Willis E. Ray Adviser Dr. Donald G. Lux Faculty of Industrial Technology Education Dr. F. Joe Crosswhite ACKNOWLEDGEMENTS

The development of this study was possible only through the

assistance and support of many people. The writer would like to

express special appreciation to his adviser, Dr. Willis E. Ray, and

to other members of the reading committee, Dr. Donald G. Lux and

Dr. F. Joe Crosswhite, for their fine assistance and encouragement

throughout this project.

Dr. Bruce Rogers of the Department of Education and Psychology,

University of Northern Iowa, was especially helpful during the

construction of the criterion test and during the analyses of test data. Dr. Douglas Pine, Dr. James LaRue, and Dr. Gary Browning of

the UNI Department of Industrial Technology provided valuable a ssist­

ance in the validation and improvement of the instructional materials

and criterion tests, as did Mr. Lyle Madson, of the John Deere

Research and Development Center, Waterloo, Iowa. Dr. James Albrecht

and Mrs. Linda Christensen of the UNI Department of Teaching provided

numerous helpful suggestions for writing the instructional materials

at an appropriate reading level. Mr. Robert Paulson and Mr. Robert

Conrad of the UNI Department of Teaching Media Center, and Dr. Joseph

Marchesani of the UNI Vtdeo Center were especially helpful during the development and editing of the video tapes, as was the J. S. Latta

Co., of Cedar Falls. Appreciation goes to Dr. Alvin Rudisill for making the video equipment and laboratory facilitie s of the UNI

Department of Industrial Technology available to the writer.

The writer wishes to thank Dr. James E. Robinson, Mr. Robert

Messer, Mr. Norman Swanson, Mr. Gary Needham, Mr. Duane Rippe, and

Mr. Tim Hartwig, for their assistance in carrying out the pilot study in the Cedar Falls Community Schools. The writer also wishes to thank

Dr. George Ross, Mr. Don Menning, Mr. Wayne Van Deest, Mr. Lee Stewart,

Mr. Steve Archibald, Mr. Gary Schwartz, and Mr. Jim Turner for their assistance in carrying out the experiment in the Cedar Rapids Public

Schools.

the writer wishes to thank Dr. Ross A. Nielsen, Head of the UNI

Department of Teaching,for the numerous expressions of encouragement and support which he has provided.

The writer truly appreciates the reliable assistance provided by Miss Symone Ma, Mrs. Pat Madson, and Mrs. Muriel Moe in the development and final preparation of the manuscript.

The writer expresses his deep appreciation to his wife, Carmen, for her faith and encouragement, and for assistance in preparing the manuscript. The writer is also grateful to his children, David, James,

Daniel, and Carla, for their patience throughout the years. VITA

October 15, 1939 ...... Born — Anamosa, Iowa

1 9 6 1 ...... B. A., Towa State Teachers College, Cedar Falls, Iowa

1962-1965 ...... Industrial Arts and General Science Teacher, Main Street Junior High School, Cedar Falls, Iowa

1965 ...... M. A., State College of Iowa, Cedar Falls, Iowa

1965-1969 ...... Instructor and Assistant Professor, Department of Teaching, University of Northern Iowa, Cedar Falls, Iowa

1969-1971 ...... Research and Teaching Associate, Faculty of Industrial Technology Education, The Ohio State Univer­ sity, Columbus, Ohio

1971-1973 ...... Assistant Professor, Industrial Technology, Illinois State Univer­ sity, Normal, Illinois

1973-1980...... Assistant Professor, Department of Teaching, University of Northern Iowa, Cedar Falls, Iowa

PUBLICATIONS

The foam vaporization method of metal casting. Addresses and Proceed- ings of the 26th Annual American Industrial Arts Association, 1964, 120- 122.

iv Metrics in construction. Addresses and Proceedings of the 39th National and 6th International Annual Conference of the American Industrial Arts Association, 1977, 131-132.

Production systems. Addresses and Proceedings of the 41st National and 8th International Annual Conference of tne American Industrial Arts Association, 1979, 72-73.

The Iowa handbook for introductory level production systems (ed.). Des Moines, Iowa: Iowa Department of Public Instruction, 1980, 587 pp.

FIELD OF STUDY

Industrial Technology Education

Professor Willis E. Ray, Adviser

Dissertation Reading Committee

Professor Willis E. Ray Professor Donald 6. Lux Professor F. Joe Crosswhite

v TABLE OF CONTENTS

Page ACKNOWLEDGEMENTS ...... ii

VITA ...... iv

LIST OF TABLES...... vi

LIST OF FIGURES...... vii i

Chapter

I. THE PROBLEM...... * ...... 1

Significance of the Study ...... 4 Statement of the Problem ...... 6 Statement of the Research Hypotheses ...... 7 Definition of Terms ...... 7 Assumptions of the Study ...... 11 Delimitations of the Study ...... 12 Limitations ...... 13 Summary ...... 14

II. REVIEW OF LITERATURE...... 16

Ausubel's Theory ...... 17 Literature Reviews of Advance OrganizerResearch .... 38 Meta-Analysis--Definition and Process ...... 46 Meta-Analyses of Advance Organizer Research ...... 49 Research Related to Organizer Format ...... 67 Advance Organizer Studies in IndustrialArts ...... 71 The Wisconsin Model of Conceptual Learning and Development ...... 72 Piaget's Theory of Cognitive Development ...... 78 Industrial Arts Curriculum Project ...... 84 Summary ...... 89

v i Chapter Page

III. THE DESIGN OF THE STUDY...... 91 Pilot Study ...... 91 Stimulus Materials ...... 93 Criterion Examination ...... 102 Experimental Design ...... 105 The Null H y p o th eses ...... 108 Sample Description ...... 108 Instructional Procedures ...... 110 Sequence of Treatment andMeasurement ...... 112 Data Collection and Analysis ...... 115 Summary ...... 115 IV. ANALYSIS OF DATA...... 118 Overview of Criterion TestDa ta ...... 118 Analysis of Variance ...... 123 Hypothesis Testing ...... 132 Discussion ...... 132 Summary ...... 142 V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS ...... 143 Summary of the R esearch ...... 143 Conclusions ...... 147 Recommendations ...... 148

APPENDIXES A. Advance Organizer I ...... 151

B. Advance Organizer I I ...... 179 C. Conventional Overview I ...... 200 D. Conventional Overview I I ...... 216

E. Reading I ...... 229

F. Reading I I ...... 243 G. Criterion T e s t s ...... 257 H. Test D ata ...... 278

I. Correspondence ...... 291

BIBLIOGRAPHY ...... 304

v i i LIST OF TABLES

Table Pa9e

1. Mean and Standard Error of Effect Size for Advance Organizers on Learning Retention ...... 50

2. Mean and Standard Error of Effect Size for Advance Organizers on Learning and Retention When Studies are Classified by Grade Level ...... 51

3. Mean and Standard Error of Effect Size for Advance Organizers on Learning and Retention When Studies are Classified by Subject A re a ...... 53

4. Mean and Standard Error of Effect Size for Advance Organizers on Learning When Studies are Classified by Subject Ability ...... 53

5. Mean and Standard Error of Effect Size for Advance Organizers on Learning When Studies are Classified by Organizer Presentation Mode ...... 55

6. Mean and Standard Error of Effect Size and Aural Advance Organizers on Learning When Studies are Classified by Grade Level ...... 56

7. Data Matrix for One Between-Groups and One Within-Subjects Design ...... 107

8. Characteristics of Classes in the Experimental Sample...... Ill

9. Classes by Randomly-Assigned T rea tm e n ts ...... 114

10. Summary Table for One Between-Groups and One Within-Subjects Design ...... 116

vi 11 Table Page

11. Difficulty Levels for Test I t e m s ...... 120

12. Item Description ...... 120

13. Test Characteristics ...... 121

14. Means and Standard Deviations of Test Scores by Treatment and G r o u p ...... 122

15. Adjusting Numbers to 18 Per Group ...... 129

16. Means and Standard Deviations of TestScores by Treatment and Group After Equalizing Numbers Within Each Class ...... 130

17. Analysis of Variance of Test Scores for One Between-Groups and One Within-Subjects D e s ig n ...... 131

18. Loss of Subjects From the Experiment ...... 141

ix LIST OF FIGURES

Figure Page

1. The Rote-Meaningful and Reception-Discovery Continua ...... 22

2. Stages in the Learning and Retention of a Subordinate Idea in Relation to its Dissociability S tren g th...... 33

3. Major Structural Elements in Industrial Technology ...... 86

4. Elements of Manufacturing Technology ...... 88

5. Subelements of Processing ...... 95

6. Modified Subelements of Processing Used As a Basis for the Advance O rg a n iz e r ...... 96

7. Sequence of Treatment and Measurement ...... 113

8. Frequency Polygon of Initial Test Scores for Advance Organizer Group ...... 124

9. Frequency Polygon of Initial Test Scores for Conventional Overview Group ...... 125

10. Frequency Polygon of Retention Test bcores for Advance Organizer Group ...... 126

11. Frequency Polygon for Retention Test Scores for Conventional Overview Group ...... 127

12. Levels of Material Processing ...... 165

13. Primary Processing ...... 165

x Figure Page

14. Secondary Processing ...... 166

15. Secondary Material Processing ...... 166

16. Forming ...... 167

17. Structure ...... 167

18. Structure...... 168

19. External Structure ...... 168

20. External Structure ...... 169

21. Internal Structure ...... 169

22. Internal Structure ...... 170

23. Forming...... 170

24. Separating Processes ...... 171

25. Separating...... 171

26. Combining Processes ...... 172

27. Combining ...... 172

28. Material Processing ...... 173

29. Material Processing ...... 174

30. Forming Processes ...... 175

31. Casting and Molding Processes ...... 175

32. M olds ...... 176

33. Compressing and StretchingProcesses ...... 176

34. Plastic N ature ...... 177

35. Conditioning Processes ...... 177

xi Figure Page

36. S e p a ra tin g ...... 178

37. Combining ...... 178

38. S e p a ra tin g...... 192

39. Direct Separating ...... 192

40. Direct Separating ...... 193

41. Single Point Tool ...... 193

42. Non-Direct S eparating ...... 194

43. Non-Direct Separating ...... 194

44. Fracturing ...... 195

45. Agent Separating ...... 195

46. Mixing Processes ...... 196

47. Mixing Processes ...... 196

48. Coating Processes ...... 197

49. Coating Processes ...... 197

50. Bonding Processes ...... 198

51. Fusion B o n d in g ...... 198

52. Adhesive Bonding ...... 199

53. Mechanical Fastening ...... 199

54. Injection Molding ...... 232

55. Extrusion ...... 233

56. Blow M o ld in g ...... 234

57. Compression Molding ...... 234

58. Forging P r e s s...... 236 59. Grain Patterns Made by F o r g in g ...... 236

x i i Figure Page

60. Steps in Forging a Connecting R od ...... 237

61. Cold-Heading Process ...... 237

62. Steps in Forging a P a r t ...... 238

63. Parts of a P r e s s ...... 239

64. Blanking Operation ...... 240

65. Shell Drawing With Matched Die s ...... 240

66. Embossing ...... 241

67. Bending on a B r a k e ...... 241

68. Arc Welding ...... 244

69. Resistance Welding ...... 244

70. Gas Welding ...... 245

71. Stretch Drawing ...... 246

72. Deep D raw in g ...... 247

73. Drawing W i r e ...... 247

74. Drawing P i p e ...... 248

75. Turning on a L a t h e ...... 249

76. Movement of the Tool and Workpiece on a Lathe ...... 249

77. Boring on a L a th e ...... 250

78. Facing on a L a th e ...... 250

79. Tapering on a L a th e ...... 251

80. Drilling a Hole...... 252

81. Operations Which Can BePerformed on a Drill Press . . 252

82. Reaming a H o l e ...... 253

83. Types of Threaded Fasteners ...... 254

x ii i Figure Page

84. Horizontal Milling ...... 255

85. Vertical Milling ...... 255

86. How a Grinding Wheel C u ts ...... 256 CHAPTER I

THE PROBLEM

A great deal of effort has been put forth over the past fifteen years to revise curricula and teaching practices in industrial arts at the secondary school level. Considerable effort has been devoted to analyzing the major systems which operate to produce industrial material goods and services for society, to reanalyzing and resynthe- sizing the knowledge base for industrial arts, and to the development of instructional models and materials which give more adequate consideration to the characteristics of the learner and to efficient learning.

Two of the prominent outcomes of this effort have been the identification of technological knowledge as the discipline base for industrial arts and the subsequent generation of taxonomies of industrial-technological knowledge which comprise the content and processes (substance and syntax) of industrial technology as an organized discipline of knowledge. Technology has been interpreted more broadly as a major branch of human knowledge, and the components of technological knowledge have been defined more precisely. Logic­ ally derived taxonomic structures have evolved which are more

1 2 inclusive of all parts of industrial-technological systems than were former industrial arts content organizers--organizers which were derived primarily through trade and job analysis. These logical structures, representing the collective wisdom of scholars in the field, have become the new definition of industrial technology, and are serving as the basic framework of organizers for emerging curr­ icula in industrial arts.

Given a basic framework of content organizers, i t remains for the teacher to find ways to relate the logical structure of a body of knowledge to the psychological structure of the learner and to make logically meaningful material psychologically meaningful to the learner. Ausubel (1964) states i t this way:

Subject-matter content can at best have logical or potential meaning. Potential meaning becomes con­ verted to actual meaning when a particular individ­ ual , employing a meaningful learning set, incorporates a potentially meaningful proposition or unit of infor­ mation within his cognitive structure, (p. 223)

In his pursuit of answers to the problem of converting logical meaning to psychological meaning, Ausubel (1963) has developed a theory of meaningful verbal learning and retention called Assimilation

Theory. Ausubel's theory involves a teaching model which uses advance organizers, introductory material presented to the learner prior to the actual learning tasks at a higher level of abstraction, generality, and inclusiveness than the learning task itself. According to

Ausubel's theory, the function of the advance organizer is to provide ideational scaffolding in the cognitive structure of the learner for the stable incorporation and retention of more detailed and different­ iated material which is to follow in the learning passage (p. 29). Ausubel believes that the learner's cognitive structure is organized hierarchically in terms of highly inclusive conceptual traces. As new hierarchical structures of ideas are transmitted to the learner, these structures provide the learner with power to continue his own learning and to solve problems.

Ausubel identifies the transmission of knowledge as the most basic function of the school. His theory focuses on how individuals learn and retain organized bodies of meaningful material. Ausubel promotes expository teaching procedures as the most efficient means of attaining this end.

While Ausubel recognizes that the development of problem-solving ability is an important objective of education, he does not recognize problem-solving activities or the discovery approach as a practical means of transmitting subject matter content (p. 19). In contrast,

Ausubel theorizes that laboratory work and problem solving are not genuinely meaningful experiences unless they are built on a foundation of clearly understood concepts and principles, and unless the constit­ uent operations of those experiences are themselves meaningful.

Research on the use of advance organizers has been sporadic and inconclusive. Barnes and Clawson (1975) reviewed thirty-two studies done with advance organizers or some variation. After using a number of variables as a means of comparison--length of study, ability level of subjects, grade level of subjects, type of organizer, and cognitive level of the learning tasks—these researchers concluded that no clear patterns had emerged regarding the facilitative effects of advance 4 organizers. Other research, reviewed in Chapter II, indicates that advance organizers tend to have a facilitative effect.

Significance of the Study

To date, few researchers have investigated the effectiveness of

Ausubel's advance organizer theory in teaching industrial-arts-related subject matter. Dawson (1965) conducted the f ir s t experiment of this type using advance organizers to teach eighth-grade students about plastics properties and processes. Pucel (1966) used what he called directive and non-directive organizers to teach metalworking and communication concepts to post-secondary vocational school students.

Kirkwood (1971) compared the use of an advance organizer with a motivational introduction in his teaching of college undergraduate elementary education majors. Of these studies, only one dealt with secondary level students. Ausubel's original studies (1960) were with university students, and advance organizer studies in general have tended to use university students because of their availability for experimental studies. This study was undertaken to provide addi­ tional research evidence of the effectiveness of advance organizers in teaching industrial arts subject matter at the junior-high school level.

Earlier industrial-arts-related studies have generated their advance organizers from standard textbook and information sheet for­ mats. These formats were determined largely by a trade-and-job analysis technique. The trade-and-job analysis technique generated materials which provided only a limited perspective of the socio-economic institution referred to as industry. This technique

did little to develop and integrate an organized body of technological

knowledge.

During the past fifteen years a considerable amount of effort

has been directed toward taxonomizing a logical knowledge structure

for the study of industrial technology which is more inclusive of all

important elements. The Industrial Arts Curriculum Project, the

largest and most influential curriculum project for junior-high

industrial arts to date (Householder, 1972), has had a major impact on

industrial arts through its provision of materials based on a broad-

based taxonomy of the knowledge of industrial technology. Practition­

ers and other curriculum projects have since adopted or adapted a

large part of these knowledge structures for use in the classroom.

The knowledge structures generated by the Industrial Arts Curr­

iculum Project and similar projects are in harmony with Ausubel's

theory about the usefulness of organized bodies of knowledge. The

present study is the f ir s t to utilize elements of the taxonomies

described above as a base for generating advance organizers and re­

lated instructional materials for experimental purposes.

Technological study encompasses at least three major elements of

knowledge: knowledge of a formal, descriptive, and prescriptive

nature; knowledge of the principles of practices; and actual perform­

ance of technical practices (Towers, et a l.). Much of this knowledge

is verbal or symbolic in nature. Ausubel's theory offers a possible

solution to the problem of teaching a significant amount of verbal material—material basically unfamiliar to most junior-high students because they have not had much opportunity to have formalized instruct­ ion in industrial technology at the elementary school level—as well as accomplishing performance of technical actions within the relatively limited time available during the typical class period.

The idea of using organizers to facilitate verbal learning has been discussed for nearly seventy-five years, but relatively little research has been done with the use of cognitive organizers. When one considers the vast amount of research which has been done with behaviorist and cognitive-field theories other than Ausubel's, the total amount of research with Ausubel's theory is exceedingly small.

The amount of work which has been done with advance organizers in industrial arts is considerably smaller. This study was designed to add to the research base in both contexts.

Statement of the Problem

The problem investigated in this study was the comparative effectiveness of an advance organizer and a conventional overview on junior high school students' learning and retention of material pro­ cessing concepts which were presented in the form of text-like read­ ings. This study compared the initial learning and retention of two groups of students after each group had received a specified sequence of instruction. As such, this study was designed to contribute evidence about the effectiveness of Ausubel's Assimilation Theory, and the relative effectiveness of advance organizers in teaching industr­ ial arts subject matter. Statement of the Research Hypotheses

The following research hypotheses were postulated:

1. Students who receive the advance organizer prior to reading the learning passage of industrial arts content will achieve signifi­ cantly higher scores on a multiple choice test of initial learning than will students who receive the conventional overview prior to reading the learning passage.

2. Students who receive the advance organizer prior to reading the learning passage of industrial arts content will achieve signif­ icantly higher scores on a multiple choice test of retention than will students who receive the conventional overview prior to reading the learning passage.

Definition of Terms

Several specialized terms are used throughout this study. These terms are:

Advance organizer. Ausubel (1978) has defined an advance organ­ izer as "introductory material which is structured at a higher level of generality, abstractness, and inclusiveness than the material it introduces" (p. 171). The intended function of the advance organizer is to promote learning by providing a set of overarching concepts in the learner's cognitive structure within which specific ideas can be subsumed. Theoretically these concepts are hierarchical in nature.

As a generalized model, an advance organizer subsumes all general classes, then various subclasses, and finally specified ideas. The 8

concepts for the advance organizer used in this study are based upon

a hierarchical taxonomy of material processing concepts.

Cognitive Structure. Ausubel (1978) defines cognitive structure

as "the total content and organization of a given individual's ideas; or, in the context of subject matter learning, the content and organiz­ ation of his or her ideas in a particular area of knowledge" (p. 625).

Concept. Ausubel (1978) has defined concept as "objects, events, situations, or properties that possess common critical attributes

(despite diversity along other dimensions or attributes) and are designated by some sign or symbol, typically a word with generic meaning" (p. 625).

Experimental group. Experimental group refers to student groups or classes which received video-taped advance organizer presentations prior to reading the printed learning passages read by all groups.

Conventional group. Conventional group refers to student groups or classes which received video-taped conventional overview presen­ tations prior to reading the printed learning passages read by all groups.

Advance organizer video tapes. Two video tapes, each of approx­ imately ten minutes duration, were developed to present a hierarchical model of industrial material-processing concepts to the experimental groups. Block diagrams or charts, an oral narration, and simple demonstrations with common materials were used to define, illustrate, and show relationships among various categories and levels of the industrial material-processing hierarchical model. Simple analogies were used to relate the relatively abstract organizer concepts to what 9 was assumed to be the common experience of learners involved in the experiment. The f ir s t video tape presented the three basic concepts of the material-processing model—forming, separating, and combining— and an elaboration of the subelements of forming processes. The second video tape elaborated on the basic subelements of separating and combining processes.

Conventional overview video tapes. Two video tapes, each of approximately ten minutes duration, were developed to present industrial material processing concepts to the conventional groups.

These tapes presented an overview of specific processes described in the printed learning passages. Some of the same charts, terms, demon­ strations, and analogies used in the advance organizer video tapes were also used in the overview tapes. Definite contrasts between the advance organizer and the overview tapes were produced in the follow­ ing ways: using terms at a more abstract and inclusive level in the advance organizer tapes vs. using the same terms at very specific levels in the overview tapes; focusing on the hierarchical relation­ ships which exist among major process groupings in the advance organizer tapes vs. presenting concepts in a more random order in the overview tapes; and by emphasizing broad principles of material processing in the advance organizer tapes vs. focusing on specific processes in the overview tapes.

Learning passage. Two learning passages were developed. Each passage was designed to be adequately studied by subjects in about twenty-five minutes. The learning passages were written and illus­ trated narrative materials about specific kinds of forming, separating, 10 and combining practices such as extrusion, drilling, and welding. The

passages were typical of the type of material found in standard

industrial arts textbooks. The learning passages were written at

approximately the seventh-grade reading level as measured by the

computer program STAR (Wilhelm, not dated). Topics for the learning

passages were presented in a random fashion rather than being organized into conceptual groups. This was done to eliminate the organizing effect of the reading passage as much as possible. The learning passages served as the sole base for developing the learning and retention criterion examinations.

Initial learning. Initial learning was defined as the extent to which subjects were able to understand, apply, and relate information from the learning passages the day following the final instructional period. Initial learning was measured by an objective-type paper- pencil test which was developed for the experiment.

Retention. For the purposes of the present study, retention was measured by administering a rearranged version of the initial learning criterion examination three weeks after the initial learning measure­ ment. The order of the questions was rearranged on the retention test.

Material processing. This term was used to refer to three basic groups of industrial processes—forming, separating, and combining.

Each process group was further defined by the advance organizers. 11

Assumptions of the Study

Assumptions relevant to this study were:

1. A principal task of the school is to transmit meaningful

verbal knowledge.

2. It is important that junior-high students learn organized bodies of knowledge, particularly a body of industrial-technical

knowledge which includes material-processing principles.

3. Verbal learning, problem solving, and technical perfor­ mance are necessary ingredients in the study of industrial technology.

These three types of activity are interdependent. Advance organizers offer potential for improving the efficiency of verbal learning in industrial technology, and hence, problem solving and technical performance.

4. A learner's cognitive structure is organized hierarchically.

Learning hierarchical concepts will facilitate the learning of content at a more specific level.

5. Subjects used in this experiment were relatively unsophisti­ cated with respect to their understanding of the concepts of forming, separating, and combining. Students had no prior knowledge of the content of the advance organizers and had limited prior knowledge of the specific content contained in the learning passages.

6. The size of the sample was adequate for the purposes of this study.

7. The potential existance of a "Hawthorne effect" was equally present at both levels of the treatment. 12

8. The physical environment had no difference in effect upon students. I he two school environments were essentially the same.

9. The content of the advance organizers, learning passages, and examinations was appropriate for the grade levels of the students involved.

10. The advance organizers were developed at sufficient levels of abstraction, inclusiveness, and generality to serve as anchoring concepts in students' cognitive structures. The industrial-technical taxonomies used as bases for developing the advance organizers were sufficiently sophisticated to provide a broad logical base of subsuming concepts for junior-high instruction.

Delimitations of the Study

The following delimitations ^reduction of scope) were set for the study:

1. Only six half-periods of instruction and testing were used for the experiment. Limitation of the amount of time taken from the regular school curriculum was an important factor in obtaining permission to conduct the experiment.

2. The independent variables pertaining to teaching methods were delimited to an advance organizer method and a conventional overview method.

3. The experiment was delimited to the use of verbal learning without any corresponding laboratory activity. 13

4. Instruction was delimited to viewing video tapes and reading written learning passages. There was no direct teacher-student

interaction related to the learning objectives of the experiment.

5. The content of all instructional materials was delimited to

industrial production aspects of three material-processing organizers

defined as forming, separating, and combining. Other aspects such as management and personnel practices were not considered.

6. Learning measurements were delimited to initial learning and

retention. Retention measurement was delimited to one observation three weeks after instruction.

7. The experiment was delimited to measurements of cognitive achievement and retention. Affective and psychomotor measures were not parts of the study. Measures of achievement did not differentiate among various cognitive levels of learning.

8. The experiment was delimited by the availability of volun­ tarily cooperating schools, teachers, and students. Student groups were delimited to intact classes.

9. Criterion measures were delimited in form to printed multiple-choice examinations.

Limitations

This study was conducted under the following inherent limitations

(shortcomings):

1. The study was short-termed in nature. Instruction occurred over a period of four days. Care must be exercised in making 14 generalizations about the effectiveness of advance organizers when used in the same manner over a longer period of time.

2. The advance organizers were complex and lengthy in relation to the limited amount of specific instruction. Time allotments for presentation of the advance organizers and related instruction were minimal in terms of number and complexity of concepts used.

3. The media used to present the instruction may have distorted the usual classroom situation. The personal relationships between students and teachers were subdued for control purposes to assure accurate replication and fidelity of instructional treatments from group to group. Instruction did not entail technical performance activities which are typical in the industrial arts classroom and may have had a negative motivational effect. A conscious effort was made to integrate "hands-on" activities--in the video tapes—from the regular curriculum with the experimental instruction in order to main­ tain student interest and promote positive attitudes toward particip­ ating in the experiment.

Summary

Chapter I has described the significance of the study and has stated the problem. This chapter also listed the research hypotheses and defined special terms. Finally, this chapter listed a number of assumptions, delimitations, and limitations for the study.

Chapter II will present a selected review of pertinent lit e r ­ ature. This review will include a description of Ausubel's 15

Assimilation Theory, a review of literature reviews of advance organ­ izer research, a discussion of meta-analyses, and a review of two meta-analyses of advance organizer research. Chapter II will also review research related to advance organizer format, advance organizer research in industrial arts, the Wisconsin Model of learning, and

Piaget's model of development. Finally, Chapter II will review pertinent aspects of the Industrial Arts Curriculum Project as they are related to the development of an advance organizer for this study.

Chapter III will describe tne pilot study, the creation of stimulus materials, and the development of the criterion examination.

Chapter III will also present the experimental design, a statement of null hypotheses, a description of the sample, instructional procedures, the treatment sequence, and a description of data collection and analysis procedures.

Chapter IV will present an overview of test data and the analysis of the data by analysis of variance. Findings related to the rejection or failure to reject the null hypotheses are also listed in this chapter. A discussion of findings is presented after analysis of the data.

Chapter V will summarize major topics of the dissertation.

Finally, Chapter V will present the conclusions and recommendations of the study. CHAPTER II

REVIEW OF LITERATURE

This chapter presents a selective review of literature which is concerned with or related to advance organizer research and Ausubel's

Assimilation Theory. Information for this review was gathered from a number of sources. A computerized system called Bibliographical

Retrieval Services, Inc., was used to search the ERIC data base for pertinent references. Ausubel's books (Ausubel, 1963, 1968, 1978;

Ausubel & Robinson, 1969) were key sources. Dissertation Abstracts

International, Psychological Abstracts, Education Index, and the bibliographies of numerous other books and periodical articles were also used to identify pertinent sources.

This chapter is organized into eight sections. The first section discusses Ausubel's theory in context with other learning theories, and then describes the basic elements of the theory itse lf. The second section is a review of literature reviews on advance-organizer research which have received wide publication and comment. The third section describes the research procedures called meta-analysis and reviews two meta-analyses of advance-organizer research: Luiten's

16 17 research and Kozlow's research. Section five deals with, organizer format, a topic of particular importance to this study since the organ­ izer used in this experiment departs from the conventional organizer format. Section six reviews the limited amount of research which has been done with advance organizers in the industrial arts field.

Section seven deals with two contemporary models of cognitive learning theory and development which have some parallelism with Ausubel's theory. Finally, section eight describes the development by the

Industrial Arts Curriculum Project of a taxonomy of industrial material processing which was used to develop the advance organizer used in this study.

Ausubel's Theory

Ausubel's Theory in Context

The National Society for the Study of Education (McConnell, 1942) grouped learning theories into three classes: conditioning, connect- ionism, and field theory. Novak (1977, p. 76) maintains that Skinner's behaviorist philosophy which was set forth in The Behavior of

Organisms: An Experimental Analysis (1938) has dominated the field of psychology in North America. Hilgard and Bower's fourth edition of

Theories of Learning (1975), a classic introductory psychology text, is s till concerned mainly with behaviorist theories. Berliner and

Gage (1976) note that the 1960's saw a continuing rise in Skinner's behaviorism, but that cognitive psychology (most closely related to field theory) continued to influence educational thought and practice. 18

Ausubel's Assimilation Theory fits into the cognitive psychology group. It is a relatively new theory. The f ir s t comprehensive discussion of his ideas was published in his book The Psychology of

Meaningful Verbal Learning (1963). Although Ausubel has published numerous articles, his ideas have not been widely accepted. Novak

(1977, p. 76) notes that prior to receiving the E. L. Thorndike Award from the American Psychological Association, most of Ausubel's research papers and books were rejected by editorial boards with prominent APA members. Two successive books (Ausubel, 1968; Ausubel, Novak &

Hanesian, 1978) have helped to clarify Ausubel's Assimilation Theory.

His theory has received a considerably larger amount of attention in research literature and among doctoral students since receiving the

Thorndike award.

In 1950 (Berliner & Gage, 1976), the National Society for the

Study of Education recognized that learning theories alone were not sufficient to solve educational problems, and encouraged the develop­ ment of models for teaching (theories of instruction). Gage (1964, p. 268) reiterated the feeling that theories of learning were of limited usefulness until they are transformed into theories of teach­ ing, and that l i t t l e progress had been made toward bridging the gap between laboratory psychology and the study of school learning.

Gagne (1976, p. 21) has written that "the central purpose of teaching is the promotion of learning in individuals called students."

Whatever particular teaching methods are used, or style the teacher may choose for any given occasion, "decisions are based upon the teacher's understanding of what is happening to the student as learner; 19 that is, they are influenced by the teacher's conceptualization of the processes of learning and the expected outcomes to which these processes lead."

Gagne emphasized that a model of learning processes was an essential framework for describing the activities of teaching which are designed to support and influence learning. He posed three quest­ ions which should be considered when relating the actions of the teacher to learning. They are:

1. what are the processes involved in learning, retention and transfer of learning? (Processes of learning) 2. What is the sequence of transformations brought about by these processes? (Phases of learning) 3. What kinds of outcomes of learning processes can be inferred from human performance? (Capabilities and dispositions produced by learning) (p. 22)

Gagne (p. 31) classifies outcomes of learning into five categ­ ories: verbal information, intellectual skills, cognitive strategies, attitudes, and motor sk ills. Although somewhat different than Gagne's explanations, Ausubel's theory provides answers for the first two of the above questions, and focuses on one of the outcomes, the learning of verbal information.

Ausubel (1963, 1968; Ausubel, Novak & Hanesian, 1978) believes that psychological principles of learning, particularly as presented from the behaviorist viewpoint, have born little or no relationship to classroom teaching because they have been uncritically extra­ polated from research on animal and rote learning. Ausubel charact­ erizes much of the psychological research in learning theory as 20

focused on animal learning or on short-term and fragmentary rote or

nonverbal forms of human learning, rather than on learning organized

bodies of meaningful material. Berliner and Gage (1976) acknowledge

that laboratory laws of learning are untrustworthy guides for class­

room practice, and assert that implications for instruction are not

developed strictly from general theories, but continue to rely on

tentative learning models which are based on empirical research.

Ausubel's Assimilation Theory contains an inherent learning model, i.e ., an advance organizer which is developed in a prescribed way and administered in a prescribed manner. The next section con­

tains a review of the basic elements of Ausubel's theory.

Ausubel's Assimilation Theory

Meaningful Learning. Ausubel's Assimilation Theory centers on

a concept of meaningful learning. Explained in simple terms, Ausubel

refers to meaningful learning as a process by which new information

is related to a relevant aspect of the individual's existing knowledge

structure. Ausubel refers to specific parts of the individual's

cognitive structure as subsuming concepts or subsumers. During meaningful learning, new information is assimilated into existing

relevant subsumers. As the new information is assimilated, the existing subsumers are modified. New meaningful learning results

in further growth and modification of existing subsumers. The size and complexity of an individual's subsumers are determined by the

individual's experience. 21

In contrast, Ausubel believes that information which is learned by rote is not linked to relevant concepts in cognitive structure, but is stored arbitrarily. If relevant concepts or subsumers do not already exist in the individual's cognitive structure, the new information must be learned by rote.

Others have recognized the importance of meaning as a factor in learning. Lyon (1914) and Jones and English (1926) demonstrated that meaningful learning does not proceed in the same way as rote learning. Reed (1938) urged that more attention should be focused on meaning as a learning factor. Anderson and Myrow (1971) report a recent research trend toward studying potentially meaningful verbal learning material rather than rote learning material, but the learn­ ing process continues to be explained in rote learning terms.

The Rote-Meaningful and Reception-Discovery Continua. Ausubel

(1978) maintains that all classroom learning can be located along two independent continua: a rote-meaningful continum and a recept- ion-discovery continuum. He asserts that much confusion has existed because many people have axiomatically come to regard all reception learning (based on expository teaching) as rote and all discovery learning as meaningful. In reception learning the principal content is presented to the learner who is then required to actively and meaningfully relate it to relevant aspects of his cognitive structure.

In discovery learning, the principal content must be discovered independently by the learner before it can be assimilated into cognit­ ive structure. Figure 1 illustrates the relationships of these two continua as explained by Ausubel. 22

Meaningful Clarification Well designed Scientific learning of relationships audio-tutorial research between concepts instruction (new music or architecture)

Lectures Most routine or "research" or most intellectual textbook production presentations

School 1aboratory work

Rote Multiplication Applying Trial-and-error learnings tabl es formulas to "puzzle" solutions solve problems

Reception Guided Autonomous learning discovery discovery learning learning

Figure 1. The Rote-Meaningful and Reception-Discovery Continua (Ausubel, 1978, p. 25)

According to this figure, there are also transitional types of learning which share properties of both rote and meaningful learning.

It is possible for reception and discovery learning to occur con­ comitantly just as it is possible for meaningful and rote learning to occur at the same time.

Ausubel sets two conditions under which either discovery or reception learning are meaningful. The first condition is that the 23 student employs a meaningful learning set—a disposition to relate new learning material meaningfully to his existing cognitive structure.

The second condition is that the learning task itself must be potentia­ lly meaningful. It must be plausible or sensible material which can be related in a nonarbitrary and substantive fashion to the individual learner's idiosyncratic cognitive structure. Meaningful learning, however, is not synonomous with the learning of meaningful material.

Unless the material is related to the individual's cognitive structure nonarbitrarily, it has not been learned meaningfully. Material is potentially meaningful if it has logical meaningfulness. It is not psychologically meaningful unless it can be related nonarbitrarily to the idiosyncratic cognitive structure of the individual.

Ausubel (1978) maintains that most classroom learning, especially in older students, is meaningful reception learning and that most of the understandings learners acquire both in and out of school are presented rather than discovered. He asserts that most meaningful material is presented verbally. He acknowledges, however, that for other types of learning, and in younger learners, "some degree of rote and discovery learning is indicated" (p. 3).

Ausubel (1961) believes that reception and discovery learning differ with respect to their principal roles in intellectual develop­ ment and functioning. Large bodies of subject matter are acquired principally through reception learning, whereas everyday problems of living are solved through discovery learning. Discovery learning is commonly used in the classroom to "apply, extend, clarify, integrate, 24

and evaluate subject matter knowledge and to test comprehension"

(Ausubel, 1978, p. 25). Meaningful reception learning is important

to education because it is an efficient means of acquiring and storing

the vast quantity of ideas and information from any field of knowledge.

It is superior to rote learning which only permits the acquisition

and retention of a few discrete items of information over a limited

period of time.

Kinds of Meaningful Reception Learning. Ausubel (1978)

distinguishes three kinds of meaningful reception learning: repres­

entational learning, concept learning, and propositional learning.

Representational learning is closest to rote learning, and occurs

when arbitrary symbols are equated in meaning with their referents

(objects, events, concepts). The symbols must signify the meaning

of the referents to the learner to be meaningful.

Near the end of the first year of life, the child acquires the

general insight that i t is possible to use a symbol to represent any

significate. By generalizing subverbally and intuitively from many exposures, the child learns that different referents have different

names, and different exemplars of the same referent have the same name. This "naming" (vocabulary learning) establishes an equivalence

between first-order symbols and concrete images.

Later, words become concept names and can be related to more

abstract, categorical cognitive content. As denotive meanings of words are combined with the individual's affective and attitudinal reactions, the words also take on a connotative meaning. 25

Ausubel believes language is an important vehicle for meaningful reception and discovery learning. Language increases the manipula- bility of concepts and propositions, aids in the refinement of subverbal understandings, and clarifies meanings, making them more precise and transferable. In contrast to Piaget, Ausubel believes that language plays an integral process role in thinking, thus serv­ ing more than simply a communicative role.

Ausubel (1978) defines concepts as:

abstracted criteria! attributes that are common to a given category of objects, events, or phenomena, despite diversity along dimensions other than those characterizing the criterial attributes shared by all members of the category, (p. 86)

The second type of meaningful verbal learning, concept learning, is an especially important aspect of Ausubel's Assimilation Theory because individuals are thought to interpret "raw" perceptual experience in terms of the particular concepts in their cognitive structure. Just as representational learning provides the building blocks for concept formation, concepts are thought to form the building blocks for meaningful reception learning of propositions and for generating meaningful problem-solving propositions.

According to Ausubel the individual's comprehension and meaning­ ful problem-solving ab ilities are dependent upon the availability in cognitive structure of both superordinate concepts (for sub- sumptive concept acquisition) and subordinate concepts (for super­ ordinate concept acquisition).

Ausubel describes two principal types of concept acquisition, namely concept formation and concept assimilation. Although concept 26

formation can occur at any age, Ausubel believes that i t takes place most often with preschool children, and that concept assimilation is

the dominant mode of concept acquisition for older children and adults.

Very few concepts, according to Ausubel, are learned by the process

of concept formation in older children and adults.

Ausubel believes that discovery learning activities are partic­

ularly appropriate at the preschool and early elementary school levels for promoting concept formation. He also advocates discovery

learning for older age levels during the early stages of exposure to a new discipline. Ausubel (1978) regards "guided discovery" as the most effective form of "discovery" teaching, but classifies guided discovery as a variant form of expository teaching that is very simil­ ar to Socratic questioning (p. 561).

According to Ausubel (1978), a number of psychological processes are involved in concept formation. They include discriminative analysis, abstraction, differentiation, hypothesis generation and testing, and generalization (p. 92). Ausubel agrees with Vygotsky

(1962) that most of the information for concept formation is generated

in laboratory-type situations. In these situations there are numerous opportunities for the inductive identification of common criterial attributes from a large array of instances which may or may not belong to a particular class of stimuli. Criterial attributes of a concept are acquired through direct experience and through successive stages of hypothesis generation, testing, and generalization.

As the child's vocabulary increases through representational learning and concept formation, the potential for acquiring concepts 27 by assimilation becomes available. Criterial attributes for new concepts can be defined using existing referents in the individual's cognitive structure. Ausubel maintains that during later elementary- school years, concept assimilation can occur with the aid of concrete- empirical props (tangible examples of concept attributes). By the junior-high level, according to Ausubel, the learner can dispense with these props and relate criterial attributes directly to his or her cognitive structure.

Ausubel calls the third type of meaningful reception learning propositional learning. Propositional learning involves learning the meaning of a composite idea made of a combination of concepts.

The learning occurs in propositional form rather than in terms of what individual words or combinations of words represent.

Propositional learning is subdivided into three categories: subordinate or subsumptive learning, superordinate learning, and combinatorial learning. Subsumptive learning takes place when the student relates a logically meaningful proposition to his idiosyn­ cratic cognitive structure. Such learning is called derivative subsumption if it simply provides an additional example or supports an idea which is already in cognitive structure. If subsumptive learning results in an extension, elaboration, modification, or qualification of previously learned propositions, the learning is classified as correlative subsumption.

Ausubel believes that the individual's cognitive structure is organized hierarchically with respect to level of abstraction, generality, and inclusiveness of ideas. Accordingly, most new 28 propositional meanings fall into subordinate relationship with existing elements of cognitive structure. New meanings are subsumed under more inclusive and general ideas, thus perpetuating the hierarchical nature of cognitive structure.

Ausubel (1978) believes that once subsuming concepts are adequately established in cognitive structure, learning will be highly efficient because:

1. They have maximally specific and direct relevance for subsequent learning tasks. 2. They possess enough explanatory power to render otherwise arbitrary factual detail potentially meaningful. 3. They possess sufficient inherent stabil­ ity to provide the firmest type of anchorage for newly learned detailed meanings. 4. They organize new facts around a common theme, thereby integrating the component elements of new knowledge, both with each other and with existing knowledge, (p. 58)

When the individual learns a new proposition under which several established ideas can be subsumed, the learning is superordinate.

This type of learning is often inductive in nature and results in a synthesis of the several ideas.

New propositions which cannot be subsumed under established propositions, or cannot themselves subsume ideas, are classified as combinatorial propositions. These learnings are potentially meaningful because they are made up of logical combinations of previously learned ideas which can be nonarbitrarily related to a broad background of generally relevant cognitive structure. They are not relatable to a particular relevant idea in cognitive structure, and hence are more difficult to learn and remember than subordinate or superordinate propositions. 29

Ausubel stresses that during the process of meaningful learning, a modification occurs to the newly acquired information as well as to the specific aspect of cognitive structure to which it is linked.

Ausubel calls this interaction between new information and pre­ existing ideas anchorage. This interaction or anchorage goes beyond the arbitrary kind of linkages which are a part of rote learning.

Ausubel labels the two related processes which occur when cognitive structure is modified as progressive differentiation and integrative reconciliation.

Progressive differentiation is most directly related to sub­ sumptive learning. As a result of this process, concepts are thought to be ordered into a hierarchical pyramid-like structure with the most inclusive propositions at the apex and progressively less inclusive elements forming the base.

Integrative reconciliation is most directly related to super­ ordinate and combinational learning. As a result of this process, existing elements in cognitive structure take on a new organization and new meaning. Ausubel believes that this process proceeds most efficiently when possible sources of confusion are sorted out by the teacher or by the instructional materials.

Assimilation is an active and continuous process. As progress­ ive differentiation and integrative reconciliation continue, meanings of component concepts may no longer be dissociable from the subsumers to which they are anchored. The overarching ideas are retained and specific details are lost. This results in what Ausubel calls 30 obi iterative assimilation or meaningful forgetting. Ostensibly less important details are forgotten while more general propositions are retained.

Retention and Meaningful Forgetting. Ausubel (1978) believes that the assimilation process is useful in explaining and enhancing retention for three reasons:

First, by becoming "anchored", so to speak, to a modified form of a highly stable existing idea in cognitive structure, the new meaning vicariously shares the stability of the latter. Second, this type of anchorage, by continuing during storage the original nonarbitrary relationship between the new idea and the established idea, also protects the new meaning from the interference exerted by previously learned, concurrently experienced, and subsequently encountered similar ideas. This interference is what is so damaging when learning material is arbitrarily related to cognitive structure as occurs in rote learning. Third, the fact that the new meaningful idea is stored in linked relation to the particular idea(s) in cognitive structure to which it is most relevant . . . presumably makes retrieval a less arbitrary and more systematic process. (p. 128)

Ausubel draws a clear qualitative distinction between the ways meaningfully- and rotely-1earned materials are learned and retained.

In contrast to being anchored to relevant ideas in the learner's cognitive structure, rotely learned materials rely on arbitrary associations. Retention of rotely learned materials is dependent upon efforts to strengthen and maintain this associative strength.

As such, retention of rotely learned materials is more subject to the interfering effects of similar rote materials which are learned before, 31 during, or after the initial learning task. Behaviorists refer to these effects as proactive, concurrent, and retroactive inhibition.

Ausubel postulated that incorporation of newly learned meanings into a network of relevant anchoring ideas would protect these mean­ ings from proactive, concurrent, and retroactive interferences. This projection was supported by a study of meaningful prose learning by Ausubel, Robbins, and Blake (1957). The use of conflicting mater­ ial during meaningful learning in another study (Ausubel, Stager, &

Gaite, 1968), actually facilitated retention of the original material, presumably by increasing its clarity.

Retention and retrievability of ideas in their original form are directly related to what Ausubel calls dissociability strength.

For a period of time after initial learning, assimilated ideas are dissociable from their anchoring ideas and are reproducible as individually identifiable entities. Dissociability strength is at a maximum immediately after learning. New meanings are maximally retrievable in unaltered form at this time. As the obi iterative stage of assimilation occurs, the new ideas become progressively less dissociable from their anchoring ideas. Eventually they are no longer available as entities in their own right and are said to be forgotten.

Obi iterative assimilation serves as a reduction process which makes it possible to retain more generalized and inclusive ideas.

This retention is gained at the expense of losing the highly detailed body of differentiated propositions and specific information. 32

Ausubel (1978, p. 126) has charted the stages of learning and retention as shown in Figure 2. Assimilation is not completed after initial meaningful learning. Assimilation continues over a period of time, which may include further new learning or eventual loss of retrievability of subordinate ideas.

The above example fits well with subordinate (subsumption) and combinatorial learning. Obi iterative assimilation of superordinate learning, however, conforms to a slightly different paradigm.

Ausubel maintains that in this case, although the new superordinate learning is initially less stable than the less inclusive subordinate ideas to which it is anchored, progressive differentiation causes the new superordinate learning to become more stable than the anchor­ ing ideas because the level of generality and inclusiveness is increased in the process. At this point obliterative assimilation is reversed, and the now less-inclusive, less-stable subordinate ideas are incorporated within and reduced to the generalized meaning of the newly-learned superordinate ideas.

Assimilated ideas become unavailable for recognition or recall

(nonretrievable) long after they are completely dissociable from anchoring ideas. When they reach the point where they become unavail­ able for recognition or recall, they are said to be below the thresh­ old of availability, the critical level of strength an idea must have to be retrievable. This threshold fluctuates, depending upon the conditions operating when the individual is asked to recall the newly learned material. However, much residual dissociability strength I MEANINGFUL New, Potentially related to and Established Interactional LEARNING Meaningful idea assimilated by Idea A Product ACQUISITION OF a in Cognitive A'a SUBORDINATE Structure MEANING a*

II POSTLEARNING New meaning a' A'a-^^A' + a' AND EARLY IN DISSOCIABLE (high dissociability strength} RETENTION OF from A'a1 MEANING a'

III LATER Gradual loss of A'a-^A' + a' RETENTION OF dissociability of (low dissociability strength) MEANING a' a' from A'a'

IV FORGETTING OF a' is no longer Dissociability of a' from A'a' MEANING a' effectively is below the threshold of dissociable from availability: A'a' a' is reduced to A'

Figure 2. Stages in the Learning and Retention of a Subordinate Idea in Relation to its Dissociability Strength (Ausubel, 1978, p. 126) 34 exists between the threshold of availability and the point of zero dissociability strength. The availability of dissociable ideas at the sub-threshold level can be demonstrated by hypnosis, and by the ease with which "forgotten" material can be relearned.

Three distinct phases of meaningful reception learning and retention can be distinguished in Ausubel's Assimilation Theory. The f ir s t phase involves learning in which meaningful ideas are related to relevant ideas in the individual's cognitive structure and produce a set of idiosyncratic meanings with a given degree of dissociability strength. During the second phase, retention, a gradual loss of dissociability strength occurs through the process of obi iterative assimilation. The third phase, reproduction of retained material, is related to the threshold of availability, as well as to other cognitive and motivational factors which influence the threshold and the process of reconstructing retained meanings into a verbal statement.

Ausubel postulates that if relevant anchoring ideas are unavail­ able during initial learning, or if anchoring ideas are unclear, then vague, diffuse, ambiguous, and erroneous meanings are apt to emerge during the learning phase. The same factors which promote lack of clarity during the learning phase reduce resistance to obliterative assimilation during the retention period. If there are few ideas to which new learning can be anchored, or if these ideas are relatively unstable, then much of the new learning will be lost. Finally, if ideas are repressed because of negative motivation or other factors, 35 the threshold of availability is raised and recall of available meanings is inhibited.

Based upon the foregoing discussion of assimilation theory,

Ausubel reasons that the main problems involved in acquiring the content of an academic discipline relate to efficiently acquiring the knowledge and then inhibiting the rate of obliterative assimi­ lation. The ability to control these factors is directly related to the existing cognitive structure of the individual and its major organizational properties for a particular subject-matter field at any given time. Ausubel believes that a primary way to maximize learning and retention is to influence cognitive structure through the use of advance organizers.

Advance Organizers. Ausubel's principal strategy for manip­ ulating cognitive structure in a way that will facilitate learning and minimize interference is to use organizers in advance of the learning material itself. Ausubel stresses that these organizers must be developed in light of what the learner already knows, and in terms of the specific learning material which is to be presented.

The purpose of the organizer is to furnish anchoring ideas for the learner at a superordinate level. As such, organizers are presented at "a higher level of abstraction, generality, and inclusiveness than the new material to be learned" (1978, p. 171).

Ausubel contrasts organizers with summaries and overviews which are ordinarily presented at the same level of abstraction, general­ ity, and inclusiveness as the learning material itself. In contrast 36

to organizers, summaries and overviews simply emphasize salient

points and omit less important information.

Ausubel (1978) bases his rationale for using organizers on the following points:

1. The importance of having relevant and otherwise appropriate established ideas already available in cognitive struct­ ure to make logically meaningful new ideas potentially meaningful and to give them stable anchorage. 2. The advantage of using the more general and inclusive ideas of a discipline as the anchoring ideas or subsumers (namely, the aptness and specificity of their relevance, their greater inherent stability, their greater explanatory power, and their integrat­ ive capacity). 3. The fact that they themselves (the organizers} attempt both to identify already existing relevant content in cognitive structure (and to be explic­ itly related to it) and to indicate explicitly both the relevance of the latter content and their own relevance for the new learning material, (p. 171)

In short, “the principal function of the organizer is to bridge the gap between what the 1 earner a I ready knows and what he needs to know before he can meaningfully learn the task at hand", (pp. 171-

172).

In addition to serving as an "ideational scaffolding," the advance organizer helps to increase discriminability between the learning material and similar or conflicting ideas already in cognitive structure. In case the learning material is relatively unfamiliar to the learner, an expository organizer is used in order to provide relevant subsumers in the learner's cognitive structure. 37

If the learning material is relatively familiar to the learner, comparative organizers are used to integrate new ideas with similar concepts in cognitive structure and to increase discriminability between new and existing ideas.

To be effective, the organizer itself must be learnable. To be learnable, it must be stated in familiar terms. If, for example, organizers are to be used with elementary-school children, they must be presented at a lower level of abstraction, and should make extensive use of concrete-empirical props.

The principle of progressive differentiation is used as a basic operational guide for the construction of advance organizers. Use of this principle begins with the substantive organizational problem of identifying the basic organizing concepts in a given discipline.

The most general and inclusive ideas are presented f ir s t, and then they are progressively differentiated in terms of detail and specificity. This process develops sets of concepts and propositions which are hierarchically organized in descending order of inclusive­ ness (1978, pp. 189-192).

As an extension of the progressive differentiation principle,

Ausubel advocates a spiral or circular kind of organization in presentation of organizers and learning materials so that the same topics are treated at progressively higher levels in successive parts of a course.

The principle of integrative reconciliation serves as a second operational guide for the construction of advance organizers. Simply stated, this means that significant similarities and differences 38

between ideas in the organizer must be pointed out, real and apparent

inconsistencies must be reconciled, and the organizer must be

reconciled and integrated with learning and existing cognitive

structure.

Beyond these two basic principles, Ausubel supplies no list of

operational procedures for developing the advance organizer. Although

Ausubel presents examples of written prose organizers in his own

research (Ausubel, 1960; Ausubel & Fitzgerald, 1962; Ausubel &

Youssef, 1963), i t is conceivable that advance organizers could be

developed in other forms. These will be discussed later in the Review

of Literature.

Literature Reviews of Advance Organizer Research

Barnes and Clawson (1975) reviewed 32 advance-organizer studies which were completed between 1960 and 1975. The studies were first

divided into two groups; those reporting significant facilitative

effects for advance organizers (n=12) and those reporting no

facilitative effects (n=20).

The studies were then analyzed according to selected variables.

These variables included length of treatment, student ability levels,

subject matter content, level of instruction, organizer format, and

cognitive level.

No clear pattern emerged when the studies were analyzed in terms of length of treatment. Treatment lengths ranged from one day (13

studies) to more than ten days (5 studies). 39

Eighteen of the studies reported results for students with

differing abilities. No trends were identified which indicated that

advance organizers would have a differential effect on the learning

of students with low, average, or high ability.

Barnes and Clawson analyzed the effectiveness of advance

organizers with different types of subject-matter content. No

differential effect was identifiable with respect to the facilitative

effect of advance organizers and subject-matter content

Half of the 32 studies were conducted with post-secondary level

subjects. Of these studies, half were facilitative. Advance organ­

izers did not function consistently when used at the elementary,

junior high, and senior high levels.

At that time, relatively few advance organizers of other than

prose format had been developed. Most of the studies reviewed used

written organizers. No conclusions about type of organizer were drawn.

At that time, few studies had classified learning tasks according

to cognitive level. No generalizations could be drawn relative to

this variable.

Barnes and Clawson were critical of the lack of an operational

definition of an advance organizer. A number of their recommendations

related to conducting additional studies using "operationally defined"

advance organizers. Among these recommendations were the need to

study long-term effects of advance organizers, to study the effects when longer treatment periods are involved, to conduct studies in a variety of subject areas, to conduct studies with a wide variety of nonwritten advance organizers, to conduct advance-organizer studies at 40 all age and grade levels, and to relate the facilitativ e effects of advance organizers on learning to all levels of the cognitive domain.

Lawton and Wanska (1977) were critical of the Barnes and Clawson review. They questioned the accuracy with which Ausubel's theory was presented, the global classification of research findings, and the lack of a rationale for including or excluding studies in the review. Several inconsistencies were pointed out as was the distortion which resulted because not all of the research efforts cited were independent studies.

Lawton and Wanska believed that several aspects of Ausubel's theory needed further investigation. They suggested that techniques for identifying and constructing organizers for different types of subject matter were needed. Further refinement and explanation of the relationship between the advance organizer and expository teaching techniques and learning activities also needed to occur.

In addition, Lawton and Wanska suggested several stages and factors which should be considered when developing and evaluating advance organizers. These stages and factors included: pretesting learners to establish the presence or absence of subsuming concepts, designing organizers on the basis of learner naivete' and available subsuming concepts, analyzing subject matter for high-level concepts and skills, and careful analysis of the number of concrete props needed to exemplify subject concepts. In addition they suggested the use of formative and summative tests to assess superordinate/ subordinate conceptual relationships, propositional learning, and problem-solving strategy learning, exclusion of subjects passing 41 pretests from research studies, the use of posttests which assess more than concept-definition recall or recognition, and that delayed posttests be used to determine retention (pp. 242-243).

During implementation of the advance organizers, the reviewers suggested that:

(a) Expository teaching should incor­ porate references to super- and subordinate concepts and their critical relationships, (b) the criterial attrib­ utes of high-level concepts or rules should be reidentified during related activities, and (c) an opportunity for the application of high-level concepts and high-order rules should be provided by presenting a variety of problem­ solving tasks, (p. 243)

Finally, Lawton and Wanska concluded that more stringent tests of the structure of organizers were needed before the question of whether or not organizers facilitate learning could be answered.

Hartley and Davies (1976) reviewed studies concerned with four different types of preinstructional strategies: pretests, behavioral objectives, overviews, and advance organizers. They defined the four concepts in terms of current usage, reviewed research findings, and summarized findings as they related to procedural guidelines for use of Gach strategy.

In general, it was found that pretests and behavioral objectives tended to be written in l i s t form, with questions or statements arranged in a linear order. Advance organizers and overviews were generally written in prose format, although "graphs of family-tree variety" (this phrase refers to networks in which technical terms and concepts are charted to illu strate their conceptual relationships) 42

were becoming increasingly common. A technical vocabulary at higher

levels of abstraction tended to be used for advance organizers and

behavioral objectives. More easily understood vocabulary and sentence

structure was used for pretests and overviews. Pretests and behavioral

objectives tended to be used some time prior to teaching the learning material; overviews and advance organizers were generally presented

immediately prior to instruction. Advance organizers were found to

be process oriented, to clarify, and to emphasize context, whereas

content was identified as the controlling feature for pretests, objectives, and overviews.

Hartley and Davies (1976) asserted that the design, writing, and recognition of advance organizers was difficult because no operationally defined steps for generating them were presently available, (p. 256) They were also critical of the "generality" of Ausubel's initial advance organizer studies (which all favored advance organizers) because they were mostly conducted at one univer­ sity, and no procedures for generating the organizers were described.

The reviewers concluded that initial advance-organizer studies tended to provide results favoring the use of advance organizers.

The results of later studies have increasingly tended to be more

inconclusive. The majority of studies examined used undergraduate subjects.

Lawton and Wanska (1977) were critical of the Barnes and Clawson review for misrepresenting Ausubel's theory. They were particularly 43 critical of the way in which the function of the advance organizer was presented by Barnes and Clawson.

Barnes and Clawson (1975) do not clearly distinguish between existing cognitive structure and a specifically organized cognitive structure resulting from a positive intervention by "didactic expo­ sition". The purpose of the organizer is not, as they state, to relate new learning materials to cognitive structure. Its function is to induce, through a particular form of learning, organizing and exemplary concepts, propositions and principles. The organizer is not, therefore, an inter­ mediary catalyst between existing cognitive structure and new knowledge, but becomes cognitive structure itself during an initial learning process, (p. 637)

Likewise, Lawton and Wanska were critical of Barnes' and Clawson's ambiguous and unclear comparison between the terms "organizer" and

"overview". They asserted that the resulting confusion further obscures the nature of an advance organizer and makes it unlikely that a reasonable answer to the question, "Do advance organizers facilitate learning?" can be obtained.

Other inconsistencies and errors in the Barnes and Clawson review also were noted. Among these were the failure to distinguish between

"studies" and independent "published works," which distorted the vote count on whether or not an experiment was facilitativ e; the lack of a consistent rationale for including or excluding studies for the review; and the extent to which studies using other than prose format organizers were ignored. 44

Lawton and Wanska listed several guidelines for developing and evaluating advance organizers. They were:

(a) Learners should be pretested to establish presence or absence of relevant subsumers. (b) Depending upon the learners' naivete regard­ ing subject-matter and/or "process" concepts or depending on the status of relevant subsumers possessed by the learner, the appropriate type of organizer to use should then be determined. (c) Subject-matter and/or problems should be analyzed to establish high-level concepts and/or high-order skills (which may also be expressed as problem-solving strategies). (d) Construction of the advance organizer should proceed according to a potentially valid sequence of intended presentation. (e) In constructing the organizer, the number of concrete props needed to exemplify subject concepts/process concepts/strategies should be determined, according to the naivete, age, or expected competency of the learners. (f) Related learning activities (in classroom settings) subsequent tasks (in research design), or both should be constructed so that they provide relevant particular information which, if assimilated, leads by subsumption to the extension of interrelated concepts in cognitive structure (hierarchical organization depends on a nonarbitrary, sub­ stantive relationship between both activities). (g) Subsequent tests (formative or summative) should attempt to assess (a) superordinate/ subordinate conceptual relationships; (b) propositional learning; and (c) problem­ solving strategy learning (in addition to sequential-transfer testing, vertical and lateral transfer should also be tested). (h) In research studies, subjects passing the pretest should be excluded. Only in this way is it possible to achieve non-trivial posttest data. (i) Posttests that merely assess concept-definition recall or recognition are open to rote- learning contamination. (j) A delayed posttest should also be included to determine learning retention, (pp. 242-243) 45

West and Fensham (1974) identified two ways in which prior knowledge influences the learning of science content. Citing the work of Gagnd (1965) and White (1972), they concluded that prior knowledge is a determinant of what further learning can occur.

After reviewing Ausubel's theory, and several related experimental studies, they concluded that the subject's prior knowledge also influences the process whereby new learning takes place.

The West and Fensham review points out that most empirical studies of advance-organizer effects can easily be misinterpreted if the role of the learner's prior knowledge is not considered. They note that a lack of disparity between advance organizer and control treatments could well be due to the presence of relevant subsumers prior to the experiment. While several researchers have attempted to measure the subjects' knowledge of content before treatments, l i t t l e progress and few attempts have been made toward identifying relevant subsumers prior to the experiment.

Additionally, West and Fensham speculated that the existance of relevant subsumers per se is no guarantee that they will be utilized to produce meaningful learning. They present evidence, accepted by

Ausubel, that learners may in fact use irrelevant subsumers (non- relevant familiar experience) to subsume new ideas, and thus develop a number of misconceptions as they learn new material. The develop­ ment of techniques for identifying subsumers which are relevant for a particular section of learning was cited as a major problem to be solved. 46

Meta-Analysis—Definition and Process

Glass (1976) described three levels of data analysis which can be applied to research studies. Primary analysis is the original ananlyis of data in a research study. Secondary analysis is a re­ analysis of data, either to answer new questions with existing data or to better answer original questions with better statistical tech­ niques. Meta-analysis is a relatively new term which is applied to the analysis of analyses. Glass used this term to refer to the statistical analysis of a large collection of analysis results from individual studies. The major purpose of meta-analysis is to provide a method of integrating the findings of many studies more adequately than can be done using the traditional narrative approach. Glass considers this technique especially useful when more than a few studies exist in a given area. The technique becomes increasingly useful as the number of studies increases.

Typically, reviews of literature involve three steps. First, all relevant studies are identified and gathered together. Next, sampling procedures, measurement and instrumentation, and methods of analysis are studied, and inadequate studies are discarded from further consid­ eration. Finally, the conclusions from remaining studies are compared in an effort to find consistent results. Often it is difficult to compare studies in the social sciences because of the dissim ilarity of research designs and contexts. Often, the final step in the review of literature is confusing because inexplicable contradictions are revealed. Contemporary researchers are searching for ways to pool 47 and analyze data from numerous studies in an effort to make comparison of studies more effective and to resolve conflicting results.

Light and Smith (1971, p. 432) described four general approaches to combining studies (reviewing literature) which are in current use.

The f ir s t approach is simply to lis t factors which have been shown to have an effect on the dependent variable in at least one of a group of studies. Use of this procedure often produces long lists which may not distinguish between factors which were found important in many studies and factors which could be singled out only once or twice.

Large numbers of studies defy simple summary in this manner.

The second approach described by Light and Smith focuses on one or more favorite studies from a set, excluding findings from studies which are not consistent. Glass (1976) notes that studies with inconsistent findings may often be discarded on the basis of analysis or design deficiencies. Although Glass does not condone poor design or analysis, he asserts that studies with several design and analysis flaws may still be valid. Additionally, Glass maintains that integ­ ration of research results by eliminating "poorly done" studies often discards a vast amount of important data.

A third approach to integrating or combining results of studies described by Light and Smith involves computing an overall average for relevant statistics across a complete set of studies. A summary measure which offers some protection against extreme values, such as a median is used. This procedure, however, discards a good deal of valuable information. 48

The fourth approach described by Light and Smith is called

"taking a vote". The relationship of the dependent variable and each

independent variable is classified as either significantly positive,

significantly negative, or as no significant relationship in either

direction. The number of studies in each of the three categories is

tallied. A plurality of studies in one category along with fewer

studies in the other two categories is used as a basis for declaring

the model category the winner. Glass (1976) criticized this procedure

because of its bias in favor of large-sample studies which may show only weak findings. Glass was also critical of the procedure because

it does not show how large an effect a particular treatment produces, or which is the most effective treatment among several treatments.

Meta-analysis research is used to provide a quantitative aggregation of findings. This quantitative aggregation provides a description of relationships among findings and describes the charact­ eristics of the studies analyzed. A common measure of effectiveness used in meta-analysis is called the effect size. Simply defined, effect size is the mean difference divided by the within-group

standard deviation (Glass, 1978, p. 366).

ES= h " XC

As an example, a study with an ES of .75 would indicate that the average subject in the experimental group was .75 standard deviation above the average subject in the control group. Some studies measure outcomes on more than one variable, or at more than one time. An ES is 49 calculated for each measurement. Once findings are quantified for each study, aggregate meanings can be sought through numerous types of statistical analyses.

Meta-analysis of Advance Organizer Research

Luiten's Research

Luiten, et al. (1979) identified approximately 170 published as well as unpublished advance-organizer studies, including 76 doctoral dissertations, which covered the timespan from 1960 to 1979. The number of studies analyzed was reduced to 135 when some duplicate references were deleted and when the researchers were unable to obtain

12 of the studies for review.

Applying Glass's meta-analysis technique, researchers obtained

110 effect-size statistics for learning, and 50 effect-size statistics for retention from the 135 studies. In most of the studies, knowledge acquisition was measured immediately after subject completion of the material to be learned, and retention measures were made more than

24 hours afterward. Effect sizes were averaged to determine the effect of advance organizers on learning and on retention. Possible in­ fluencing variables such as grade level, organizer presentation mode, subject ability level, and type of subject matter were examined in a similar manner. 50

Average effect sizes for advance organizers on learning and

retention are shown in Table 1.

Table 1. Mean and Standard Error of Effect Size for Advance Organizers on Learning and Retention (Luiten, 1979, p. 14)

Learning Retention

0-1 Day 2-6 Days 7 Days 8-20 Days 21 Days 22+ Days Number of Effect Sizes 110 8 17 8 9 8

Mean .21 .19 .20 .23 .30 .38

Standard Error .04 .15 .10 .16 .11 .16

The data in Table 1 reveal that advance organizers do have a facilitativ e effect on learning and retention in the average study which was reviewed. Using the interpretation of Smith and Glass (1977), and assuming a normal distribution of subject (study) scores, the mean effect size (.21) for the advance organizer on learning indicates that the average subject receiving advance-organizer treatment per­ formed better than 58 percent of the control group subjects. The advance organizer effect on retention was similar, and increased with time when compared with the control group. At 22+ days, the average advance-organizer subject performed .38 standard deviation better than the average control subject on a retention test. 51

Tahle 2 shows the average effect size for advance organizers on learning and retention when classified by grade level.

Table 2. Mean and Standard Error of Effect Size for Advance Organizers on Learning and Retention When Studies are Classified by Grade Level (Luiten, 1979, p. 14)

Learning

College Secondary Primary Special (Grad & Under) (Grades 9-12) (Grades 3-8) Education Number of Effect Sizes 40 36 30 4

Mean .26 .17 .17 .28

Standard Error .09 .06 .08 .12

Retention

College Secondary Primary Special (Grad & Under) (Grades 9-12) (Grades 3-8) Education Number of Effect Sizes 20 20 10 0

Mean .21 .26 .33 0

Standard Error .08 .10 .14 0

For learning, average effect sizes for advance organizers at the college (.26) and special education (.28)levels were greater than at the secondary (.17) and primary (.17) levels. For retention, the 52 comparative results were opposite. Advance-organizer effect on retention was most pronounced at the primary grade level (.33).

Effect was more pronounced for retention at the secondary level (.26) than at the college level (.21). No difference in effect was shown at the special education level (0.0).

Table 3 shows the effect of the advance organizer on learning and retention with studies classified by type of subject matter.

Studies were classified into four content areas: mathematics (sta t­ istics, algebra, trigonometry, physics), physical sciences (chemistry, geology, metallurgy, astronomy), biological sciences (plant and animal biology, microbiology, ecology), and social sciences ('"eligion, psychology, geography, economics, civics, a rt, language) (p. 8).

The average advance organizer effect on learning and retention was positive within all subject areas studied. The largest average effect size in learning studies was in the Social Science group (.34 standard deviation). Smaller positive effect sizes were shown in the

Physical Sciences (.15), Biological Sciences (.11), and Mathematics

(.10)groups.

The gap between advance organizer and control groups widened when retention measures were made. The effect size for retention measures of each subject area was greater than the learning effect size for all groups except in the Social Science group (ES declined from .34 to .26). The average advance organizer effect for the Physi­ cal Science group on a retention measure was .50 standard deviation above the average of the control group. 53

Table 3. Mean and Standard Error of Effect Size for Advance Organizers on Learning and Retention When Studies are Classified by Subject Area (Luiten, 1979, p. 15)

Learning

Phys i cal Biological Social Mathematics Sciences Sciences Sciences Number of Effect Sizes 24 32 21 33

Mean .10 .15 .11 .34

Standard Error .09 .06 .07 .10

Retention

Physical Biological Social Mathematics Sciences Sciences Sciences Number of Effect Sizes 13 8 15 14

Mean .17 .50 .18 .26

Standard Error .11 .18 .10 .09

Table 4. Mean and Standard Error of Effect Size for Advance Organizers on Learning When Studies are Classified by Subject Ability (Luiten, 1979, p. 15)

Ability Level

High Mi ddle -OW Number of Effect Sizes 26 9 29

Mean .23 .08 .13

Standard Error .16 .32 .09 54

Interaction of advance-organizer effect and subject ability is

shown in Table 4. Since few of the 135 studies examined this

relationship, the researchers reported average effect size for learn­

ing only.

As shown in Table 4, advance organizer subjects in the high

ability group had an average effect size almost twice that of low

ability subjects (.23 vs .13).

In most studies, advance organizers have been presented to

subjects in written form. A few studies have presented advance

organizers in aural and visual forms. Table 5 presents the average

effect size of advance organizers on learning when studies are

classified into written and aural presentation modes. The aural

category includes four studies where the subject read an advance

organizer passage while listening to it being read aloud, or viewed

an audio-visual (slide projector or movie) presentation. Again,

since studies with varying advance-organizer presentation modes

and studies which measured retention were so few in number, retention

data were not presented in Table 5.

As shown in Table 5, the average effect size for auralHmode

advance organizer studies (.37) was about twice that of written­ mode advance-organizer studies (.17). This relationship was explored

further by relating mode of advance-organizer presentation to grade

level. Table 6 shows the results of this comparison. 55

Tahle 5. Mean and Standard Error of Effect Size for Advance Organizers on Learning When Studies are Classified by Organizer Presentation Mode (Luiten, 1979, p. 16)

Presentation Mode

Wri tten Aural Number of Effect Sizes 89 21

Mean .17 .37

Standard Error .04 .14

Based on this analysis, the aural-mode advance organizer produced an average effect size nearly three times that of the written-mode advance organizer for college students (.68 vs .26 in Table 2).

The average effect size nearly doubled for primary-level subjects

(.34 vs .17 in Table 2). Although no standard error is shown, it appears that the average effect size increased or stayed about the same for special-education subjects (.37 vs .28+.12). Average effect size declined for secondary-level subjects (.11 vs .17). 56

Table 6. Mean and Standard Error of Effect Size and Aural Advance Organizers on Learning When Studies are Classified by Grade Level (■Luiten, 1979, p. 17)

Grade Level

College Secondary Primary Special [Grad & Under (Grades 9-12) (Grades 3-8) Education

Number of 6 6 8 1 Effect Sizes

Mean .68 .11 .34 .37

Standard Error .43 .07 .15 — 57

Kozlow's Research

Kozlow (1978) conducted a meta-analysis of advance organizer

studies which had been completed between 1960 and 1977. Not all of

the identified studies were retained for analysis. In order for a

study to be included in the analysis, it had to meet three criteria:

1. The study must be an experimental comparison between groups receiving an advance organizer and a control group receiving a "neutral" treatment. Neutral treatment could mean that the group received introductory passages which did not contain substantative information related to the learning activity; or a condition where the control group did not receive an introductory passage. The control group, however, could not receive some other preinstructional strategy which was designed to fa c ilita te learning. For example, a lis t of behavioral objectives, study questions, or a vocabulary l i s t could not be used. 2. The advance organizer must present a general idea intended to act as a subsumer for the learning activity to follow, or must make some attempt to enhance the learner's under­ standing of the intended subsumer. 3. The primary mode of presentation of information in the advance organizer must be prose. The number of non-prose advance organizers was thought too small to constitute a viable category for analysis, and it was more difficult to analyze the content of non-prose material, (p. 34)

Based upon these c rite ria , Kozlow's sample included 99 exper­ iments which were reported in 77 research reports. Ninety-one advance organizers were identified in the sample. Copies of 71 of the advance organizers were obtained for analysis.

For purposes of the study, two dependent variables were identified.

For the f ir s t dependent variable, Kozlow used a t-s ta tis tic for te s t­ ing the significance of difference between achievement means for the 58 advance organizer group and the control group of each experiment.

As a second dependent variable measure, Kozlow computed the probab­ ility level associated with each obtained t-statistic.

Kozlow noted (p. 46) that since the dependent variables for the meta-analysis were not used in the probabilistic sense normally associated with these statistics, it was not necessary to conform to limitations placed on their use in multiple comparisons. The s ta tis ­ tics were used as a measure of magnitude of observed difference be­ tween the means for two groups rather than as a way of assigning probabilities to accept or reject a null hypothesis.

A total of 63 independent variables were identified for use in comparing studies within the sample. These variables were grouped into five categories: characteristics of the sample, treatment administration conditions, type of subject matter, quality of research procedures, and characteristics of the advance organizers and learn­ ing materials.

Five variables were used to describe characteristics of the individual study samples. They were: sample size, grade level, learning ab ility , prior knowledge, level of achievement, and gain score.

Thirteen variables were used to describe treatment administration conditions. Many of these were dichotomous; they were either present or absent in a given study. The thirteen variables were: number of advance organizers used, number of times to read advance organizers, whether or not subjects could refer to the advance organizer while studying the learning materials, access to the advance organizer 59

outside of the experimental setting, whether or not a control intro­

duction was used in place of the advance organizer in the control

group (or some other arrangement), pretest measurement, retention

test measurement, retention time, length of advance organizer in

words, length of advance organizer in time, length of learning mater­

ial in minutes, and advance organizer length compared with learning

material length.

Seven variables were used to classify subject matter for each

study. They were: science (chemistry, physics, biology, earth

science), mathematics (algebra, geometry, calculus, s ta tistic s ),

other subjects (psychology, education, social studies, language,

religion, and the a rts), concept type, number of concepts, average

number of attributes per concept, and cognitive level of tests

(2 categories: recall and higher level).

Kozlow studied the quality of research procedures in terms of

the internal and external validity of the studies. A jury of raters was used to examine this aspect. Three variables were studied in

terms of the internal validity of the study. Two of these variables

related to the facilitative effect of studying only the advance

organizer. The other variable related to time equalization--whether

or not the control group studied learning materials for a period of

time equal to the combined time used by the experimental group to

study the advance organizer and the learning materials.

External validity variables were studied in terms of the adequacy

of data collection procedures and the appropriateness of data analysis.

Data collection procedures were analyzed in terms of three variables: 60

representativeness of sample, loss of sample, and the quality of the

achievement te st in terms of re liab ility , validity, and objectivity.

Data analysis was also analyzed using three variables: correct unit

of analysis (student vs class), Type I error, and Type II error.

Characteristics of the advance organizers and learning materials

used in sample studies were analyzed in terms of type of advance

organizer, presentation mode, reading level, kinetic structure, and

teaching strategy employed.

One variable was used to classify the advance organizer as

expository or comparative. Six variables were used to classify the

presentation mode: whether presented by reading, listening, or class­

room interaction; whether reference to concrete experience was made

in the advance organizer; whether diagrams were used in the advance

organizer; whether questions were used in the advance organizer;

whether learning materials were presented by reading, listening, or

classroom interaction; whether laboratory work or demonstrations were

used in the learning materials; whether questions were used in the

learning materials; and whether learning activities were not completely

planned by the researcher.

Two variables were identified to classify the appropriateness

of reading level; one for the advance organizer and one for the

learning materials.

Kozlow used two variables to identify the kinetic structure of

advance organizers and learning materials. Kinetic structure analysis

(Anderson, 1971, p. 7), involves examination of the serial ordering 61

of information in a verbal communication and the relatedness of

adjacent discourse units in the communication. One variable, the

commonality coefficient, was used to measure the extent to which

adjacent discourse units contain common verbal elements. A second

variable, the progression density coefficient, was used to measure

the rate at which new elements are introduced into a verbal comm­

unication.

Finally, Kozlow identified twelve variables which were related

to teaching strategies employed in the advance-organizer studies.

Using a model described by Henderson (1967, pp. 575-577), advance

organizers and instructional materials were blocked into two basic

types of instructional moves: exemplification moves which provided

examples and nonexamples of a concept; and characterization moves which provided descriptions of the attributes of a concept. A third

category of moves, metalanguage, was not used because of inability

to distinguish between characterization and metalanguage as defined

by Henderson. Instructional moves were grouped in clusters, and

teaching strategies were identified by the sequence of exemplification

and characterization moves within each cluster.

Results of Kozlow1s Meta-analysis. Sixty-eight of the 99 t-statisties were positive, indicating that the observed mean for the advance

organizer groups was higher than that for the control groups. Nine of these were significant at £<.05, and thirteen were significant

at £<.01. Twenty-nine t-s ta tistie s were negative, but none of these were significant. Two ^-statistics were zero. 62

An equal number of positive and negative t-s ta tis tic s would have been expected if the results of the research were due only to chance.

These results indicate that there was a tendency for advance organizers to show facilitative effects.

Ten of the 63 independent variables had significant correlations with both dependent variables. Seven independent variables had significant correlations with one dependent variable measure but not with the other.

Grade level was significantly correlated to both dependent variable measures (£<.01). As the grade level of subjects increased, advance organizers tended to show greater facilitative effect. Since the advance organizers tended to contain a high concentration of information, and were presented to subjects for only a brief period of time, it is possible that younger subjects had difficulty under­ standing the information which was presented. It is also possible that Ausubel's Assimilation Theory is not relevant for young child­ ren. However, researchers (Ryder, 1970) have obtained significant effects using advance organizers with young children.

Gain score of the control group was significantly correlated to both dependent variables (£<.025). There was a greater tendency for advance organizers to show facilitative effects as the gain score of the control group increased.

There was a significant negative correlation (£<.025) between the number of advance organizers used and the probability measure. 63

The correlation between this variahle and the t-statistic was also

negative but not significant. The tendency for advance organizers to

show facilitative effects decreased as the number of advance organiz­

ers placed within learning materials increased. Kozlow (p. 110)

indicates that this was probably not a length effect because the time

spent on advance organizers correlated positively with the probab­

ility statistic

Access to the advance organizer during use of the learning

materials had significant negative correlations with both dependent

variables (t>statistic, £<.1D03; probability, £<.002). Advance

organizers had less tendency to show facilitativ e effects when sub­

jects had concomitant access to the advance organizer and the learning material. Kozlow suggests that in these cases a clear distinction

may not have been made between the advance organizer and the learning material. Furthermore, the materials may simply have been given to

students as assigned readings and actual reading may not have been monitored.

The length of the advance organizer in minutes was correlated

positively with the probability measure at a significant level

(£<.046). This indicated that there was a greater tendency for the

advance organizer to show facilitative effects as the length of time

spent on the advance organizer increased. The correlation between

this independent variable and the t-statistic was also positive but not significant.

Correlation coefficients between the length of the advance

organizer in words and the dependent variables were negative but not 64 significant. A strong positive correlation (.71) existed between the length of the advance organizer in time and the length of the advance organizer in words. Kozlow (p. Ill) concluded that the time spent on the advance organizers had a greater influence on their facilitative effect than did the quantity of material contained in them. This conclusion was further supported by correlating the rate (words per minute) at which students were required to process advance-organizer information with the dependent variables. Negative correlations were obtained (-.21 for t-statistic, £«!.18; 1.24 for probability £<.12).

The length of the learning materials in minutes was negatively correlated with the probability measure (£<.020). Correlation of this variable with the t-statistic was also negative but not signi­ ficant. Advance organizers had less facilitative effect as the amount of time spent on learning activities increased. Kozlow (p. 112) attributes this relationship to a lack of definition between advance organizers and learning materials, a case similar to that described for the number-of-advance-organizers variable and the advance-organizer- during-1earning-materials vari able.

Science subject matter had significant negative correlations with both dependent variables (-.24 t-s ta tis tic £<.019; -.32 probability

£<.001). Advance organizers had less tendency to show facilitative effects when the subject matter was science. Interestingly, more than half of the advance organizer research analyzed by Kozlow used science content.

Other subject matter (psychology, education, social studies, language, religion, and the arts) had significant positive 65

correlations with both dependent variables (.30 t-s ta tis tic £<.002;

.30 probability £<.003). Advance organizers had a greater tendency to show facilitative effects when the subject matter was other than

science or mathematics.

A significant negative correlation was found between concept type and probability (£<.013). The correlation of concept type with t-statistics was also negative but not significant. Concepts were classified dichotomously as classificational and correlational or theoretical. Classificational concepts were defined as those which

"facilitate the description of phenomena through the specification of attributes that can be used to classify objects and events"

(p. 60). Correlational concepts facilitate the prediction of events.

Theoretical concepts facilitate the explanation of phenomena. For operational reasons, correlational and theoretical concepts were grouped together in Kozlow's study. The correlations for this variable indicate that there was a greater tendency for advance organizers to show facilitative effects when advance organizer main concepts were classificational.

The number-of-concepts variable had significant negative correl­ ations with both dependent variables (t-sta tis tic £<.030; probability

£<.015). As the number of concepts presented in the advance organizer increased, the facilitative effect of the organizer decreased.

There was a significant positive correlation (£<.037) between the percent of test questions judged to be answerable from information provided in the advance organizer and the t-statistic. As the number 66

of questions answerable from advance organizer information increased,

the facilitative effect of the advance organizer increased.

Significant negative correlations for both dependent variables

(t-sta tis tic £<.022; probability £<.023) were obtained when study

times were compared. Advance organizers showed a lesser tendency to

facilitate learning when the control group studied the learning materials for a period of time equal to the combined time the exper­

imental group studied the advance organizer and learning materials.

The type-of-advance-organizer variable had significant positive correlations with both dependent variables (jt-statistic £<.003;

probability £<.004). Comparative advance organizers tended to have

greater facilitative effects than did expository advance organizers.

Kozlow noted that comparative organizers tend to utilize existing

concepts in cognitive structure to a greater extent than do expository organizers.

The presentation-mode variable had significant positive correl­ ations with both dependent variables (t-sta tis tic £<.013; probability

£<.008). There was a greater tendency for advance organizers to show facilitative effects when the presentation mode was other than reading.

The appropriateness-of-reading-level-of-the-advance-organizer variable correlated positively and significantly (£<.01) with the t-statistic. Advance organizers which were written at a reading level appropriate to the grade level of subjects had a greater tendency to show facilitative effects. 67

The progression density of advance organizers correlated negatively and significantly (£<.025) with both dependent variables.

As the rate of introduction of new material increased, advance organizers tended to show less facilitative effect. The progression density of the advance organizer was a key element affecting under- standability.

Of several teaching strategy variables tested, only one had a significant correlation with the two dependent variables. The CEC strategy (characterization, exemplification, characterization) had a significant (£<.029) correlation with the ^ -statistic. This strategy, beginning with a generalization, followed with examples and with a restatement of the generalization, had a greater facili­ tative effect than the sole use (pure) of the generalization alone, the examples alone, or other serial combinations of the two types of presentation. Out of 20 advance organizers utilizing a completely pure teaching strategy, only one showed a significant facilitative effect. Other combinations of characterization and exemplification strategies showed a strong positive relationship with the dependent variable (^-statistic), but none were significant.

Research Related to Organizer Format

A number of organizer formats have been used successfully. Not all advance organizers have been developed in prose. This section reviews advance-organizer research which relates to the type of advance-organizer format used in this study. 68

Weisberg (1970) used three types of organizers to teach earth science concepts: a prose description of the ocean floor, a series of profiles of the North Atlantic Ocean floor, and the Heezeu-Tharp

Physiographic Diagram of the North Atlantic Ocean floor. The map of profiles was found to function best (jk .01); the graph functioned almost as well; and the prose organizer was not helpful in this teaching situation. Graphic organizers were most suitable for teach­ ing graphic concepts.

Pella and Triezenberg (1969) presented the concept of equalib- rium in three ways: verbally, verbally supplemented with sketches, and verbally 'Mpplemented with appropriate mechanical models. High- ability groups exposed to the model treatment earned consistently higher but not significantly higher scores than the high-ability sketch or verbal treatment groups.

Scandura and Wells (1967) used games as an organizer for teach­ ing about abstract mathematical groups and topological facts about lines, curves, arcs, and networks. Interaction between organizers and instructional materials was not significant, but the game organ­ izers were facilitating, particularly with the topological concepts.

Jerrolds (1967) found "modified advance organizers," formulated around main idea concepts, to be as effective as more extensive prose organizers in preparing students to read for retention of facts.

Organizers were also used both with and without instruction on how to use the organizer. No significant differences were found among these groups. 69

Earle (1970) presented a "structured overview"—a diagrammatic arrangement of important technical vocabulary terms—to students in both visual and verbal format in an attempt to increase mathematics achievement. The diagrammatic arrangement was intended to serve as an aid to the student in organizing existing knowledge within the structure of the particular discipline. Earle concluded that the seventh-grade students who were exposed to the structured overview learned more about the hierarchical and parallel relationships which exist among mathematics vocabulary terms than did students not receiv­ ing the structured overview. Students in the structured-overview group did not, however, perform better on a teacher-constructed content test or the standardized mathematics achievement test.

Kneen (1979) compared the effects of two types of advance organizers, guide material and a structured overview, on comprehension of a reading task. The guide material was a 500-word passage which centered around key words in the learning task. The structured over­ view was a graphic representation of key words used in the reading task. Use of the structured overview resulted in significantly greater comprehension (no level reported) than use of the guide material. The structured overview was more effective in facilitating comprehension at all reading levels—high, middle, and low ability.

Geiger (1978) studied the effects of advance-organizer format and learner personality in the learning and retention of verbal material. Geiger concluded that visual advance organizers may aid learning and retention and recommended expanded studies of the efficacy of visual organizers. 70 Bunson (1978) used two types of "advance samplers" as advance organizers with sixth-grade students prior to viewing a motion-picture film of social-studies content. The first organizer (E^) was composed of selected scenes which were copied from the film and were shown prior to viewing the film in its entirety. The second organizer (Eg) was composed of selected scenes plus "attention focusing directions".

The control group (C) reviewed the film alone. On an initial achievement test, no significant difference was found between C and

Ej. A significant difference (£<.05) existed between Ej and Eg, and a significant difference (£<.01) existed between C and E 2. On a retention test, a significant difference (£<.01) existed between C and E^ as well as between C and Eg. No significant difference existed between E^ and Eg. These differences indicate that Eg was highly effective in improving performance on the in itial test and that both

E^ and Eg were highly effective in improving performance on the retention test.

Meena (1979) compared the effectiveness of written and other graphic comparative advance organizers with use of a non-organizer control passage as introductions to an audiovisual learning task.

Both organizer treatments were superior (£<.05) to use of the non­ organizer control passage. Learners receiving the graphic comparative organizer performed significantly better (£<.05) than learners in the control group on a retention test. There was no significant differ­ ence in performance between the two organizer groups on either the learning or retention test. 71

A number of other studies employed graphic or graphic-audio organizers (Frost, 1978; Phelps, 1977; Salmon, 1977; Sherbo, 1977;

Barron, 1971; Lucas, 1972). None of these studies demonstrated significant differences between experimental and control-group performances.

Advance Organizer Studies in Industrial Arts

A review of literature related to the experimental use of advance organizers revealed that only three researchers have attempted to study the effectiveness of this technique for teaching industrial- arts-related subject matter. Dawson (1965), using industrial arts content related to the properties and processing of plastic materials, found a significant difference in initial learning and on a three- week test of retention between lower-ability eighth grade male students in an experimental group and the comparison group. Dawson's results favored the use of advance organizers for this particular group of students.

Pucel (1966) investigated the relative effectiveness of trad­ itional and two modified methods of organizing instruction sheets in the areas of metalworking and communication with lasers. He used organizers which he termed directive and non-directive. The directive organizer was a type of summary organizer; the non-directive organizer was a question or discovery organizer. Area vocational-school students were used as subjects. Pucel found no significant difference between groups as measured by mean scores on tests of initial learning, 72 retention, and transfer. No significant interaction between student ability levels and method of presentation was evident.

Kirkwood (1971) compared the use of advance organizers with a motivational introduction in his teaching of undergraduate elementary education majors. Three experimental groups were exposed to an advance organizer, a "typical" introduction, and a placebo introduction, before redeiving three consecutive lessons on mass production concepts.

The three groups learned significantly more than a control group, but did not differ significantly among treatments.

The Wisconsin Model of Conceptual Learning and Development

Conceptual learning has received increased emphasis as a focus for psychological research during the past two decades. During the same time, curriculum developers have given more attention to concepts as they specify subject matter and design instructional methods. Ausubel presents one view of concept development; Klausmeier, et a l. (1974) present another current view which has been labeled the Wisconsin Model of Conceptual Learning and Development. Klausmeier defines the term "concept" in both an individual and a public context. In the individual sense, concept is defined as "ord­ ered information about the properties of one or more things—objects, events, or processes--that enables any particular thing or class of things to be differentiated from and related to other things or classes of things" (Klausmeier and Hooper, 1974, p. 18). As the individual matures, concepts as mental constructs are acquired according to that individual's unique learning experiences and maturational 73 pattern. As public entities, concepts are societally-standardized meanings which make up the language of the society.

Klausmeier, et al. (1972) further defined concepts by describ­ ing eight concept attributes. Concepts have learnability, usability, validity, generality, power, structure, instance numerousness, and instance perceptibility.

The Wisconsin Model postulates the following four levels of attaining the same concept: the concrete level, the identity level, the classificatory level, and the formal level. An individual is thought to attain an increasingly sophisticated mastery of a concept over a period of time as opposed to attaining a final level of mastery the f ir s t time the concept is learned. Klausmeier postulates that the normative learning pattern is to attain each higher level success­ ively.

At the concrete level, the individual cognizes an object that has been experienced on a prior occasion. At the identity level, the individual cognizes an object as the same as one previously encountered, but observes it from a different spatiotemporal perspec­ tive, or through a different sense modality. At the classificatory level, the individual treats at least two instances of the same set as equivalent, but cannot name the common attributes. At the formal level, the individual can name and define the concept. In addition, the individual can discriminate and evaluate differences between instances and noninstances in terms of societally accepted defining attributes. 74

Certain cognitive operations are postulated to take place at

each of the four levels. At the concrete level, the individual attends

to the object, discriminates the object internally from other objects,

and remembers the discriminated thing. At the identity level, cognit­

ive operations include and go beyond operations at the concrete level.

An additional operation at this level results in the generalization

that two or more forms of the same thing are equivalent. At the class­

ificatory level, generalization is taken one step further to the point

that different instances are thought to be equivalent in some way.

At the formal level two tracks of operations are possible. Both

tracks are in addition to the preceding operations of previous levels of concept attainment. The first track involves discriminating and

defining the attributes of the concept, hypothesizing the relevant

attributes and/or rules, remembering hypotheses, evaluating hypotheses

using positive and negative instances, and inferring the concept.

The first and last operations of the second track are the same

as for the f ir s t track. The intermediate operation simply involves

cognizing the common attributes and/or rules from positive instances

alone. According to Tagatz (1967) elementary children up to about age 12 carry out the formal-level operations of the second track.

They are not able to hypothesize and evaluate defining attributes to

utilize information from negative instances well.

Klausmeier views the verbal-linguistic mode as the prominent mode of short- and long-term information storage in the adult. A

non-linguistic storage mode is presumed to be used by preverbal 75

children to learn concepts at the concrete, identity, and classifactory

levels. Verbal labels or other symbols are considered essential at the formal level of concept development.

According to the Wisconsin Model, concepts must be learned at the classifactory or formal level before they may be utilized in cognizing supraordinate-subordinate relationships. New operations at each level of conceptual development are thought to involve qualitative changes

in operations rather than being additions to or modifications of prior operations. Operations at each succeeding level are more highly differentiated and deal with more abstract concept attributes.

The Wisconsin Model has a number of implications for instruction.

Klausmeier classifies these into three groups: (1) predevelopment activities, (2) prematerial instructions, and (3) within-material presentations (Klausmeier & Hooper, 1974, pp. 34-40).

Predevelopment a ctiv itie s. Prior to developing instructional activities, the target population can be described in terms of internal conditions necessary for attainment of the particular concepts. These conditions include the level of vocabulary, level of reading achieve­ ment, ability to secure information from concept exemplars of various types, mastery of lower levels of the concept, and the ability to perform operations as identified in the model (Bruner, 1964; Clark,

1971; Feldman, 1972; Swanson, 1972).

Before instructional materials are developed, sets of related concepts to be included in the materials must be identified and analyzed. This task includes stating the definition of each concept by defining its attributes, delineating relevant and irrelevant 76

attributes, listing teaching examples and nonexamples, and identifying

possible examples and nonexamples to be used in testing (Markle &

Tiemann, 1969).

Another predevelopment activity involves sampling the target

population and testing the difficulty levels of concept examples and

nonexamples. Using a technique called "instance-probability analysis,"

a concept definition is given to students, together with a large set

of examples and nonexamples (Feldman, 1972; Swanson, 1972; Tennyson

& Boutwell, 1971). The percentage of students who properly classify

each example or nonexample is used to describe the difficulty level.

Finally, a set of concept instances is selected, based upon the

instance-probability analysis. Markle and Tiemann (1969) recommend that examples and nonexamples should be sufficient to vary each

relevant and irrelevant attribute.

Prematerial instructions. A number of prematerial instructions

and activities can be used to facilitate the cognitive operations of the learner. Klausmeier notes that establishing a set to learn con­

cepts rather than to memorize individual instances can do a great deal to activate operations necessary for attaining concepts at the classificatory and formal levels.

A second phase of prematerial activities involves the hier­ archical arrangement of supraordinate and subordinate concepts. The

Wisconsin Model suggests that "Concept learning is . . . facilitated

if information concerning relevant attributes and/or the appropriate

rule structure of the concept is given to the learner at the outset, 77 particularly if the attributes are not obvious and if the rule struct­ ure is complex" (Klausmeier & Hooper, 1974, p. 37).

Since proper attainment of a concept at a lower level is thought to be the prerequisite for attainment of the same concept at the next higher level, provision for recall of relevant information can facili­ tate higher level attainment. The Wisconsin Model supports the use of instructions which help the student recall relevant information.

In a sense, Ausubel's advance organizer provides this type of assist­ ance.

A fourth prematerial instruction activity involves providing the learner with decision rules with which to evaluate and classify examples and nonexamples of a concept. This activity is deemed important in cases where the concept definition is provided at the outset as well as inductive instances when the learner infers the concept by evaluating examples and nonexamples.

Finally, the Wisconsin Model places great value on verbalizing the concept name and its defining attributes as a prematerial instruc­ tion activity. Verbal encoding is believed to serve a number of functions. It facilitates the cognitive operations of discriminating attributes, formulating, remembering, and evaluating hypotheses. It facilitates conceptual attainment by allowing the individual to sort out and consider particular parts of an experience while ignoring others. It makes information processing more efficient and helps the learner read printed materials.

Within-material presentations. Thus far, suggested guidelines for activities which should precede a conceptual lesson (predevelopment 78 and prematerial) have been discussed. The following guidelines pertain to within-material presentation of the lesson.

First, the concepts must be defined within the lesson in terms of relevant attributes (Swanson, 1972; Feldman, 1972; Tennyson, 1971).

Second, properly matched examples and nonexamples of varying d iff­ iculty levels should be included for each concept. The number of examples and nonexamples, the matching to relevant and irrelevant attributes, and provision for varying difficulty levels, all affect the extent to which concepts will be overgeneralized or undergeneral­ ized (Feldman, 1972; Merrill & Tennyson, 1971; Swanson, 1972; Tennyson, et a l., 1972).

Third, the student's attention must be drawn to the defining attributes of the concept. Clark (1971) found that pointing out attributes and/or rules to the student yielded better results than relying on the student to discover attributes and rules.

Fourth, feedback regarding correctness or uncorrectness of student responses promotes higher concept attainment (Page, 1958; Sweet, 1966;

Clark, 1971; Frayer & Klausmeier, 1971. Finally, the Wisconsin Model recommends the use of questions at the end of instructional segments.

Piaget's Theory of Cognitive Development

Jean Piaget has generated volumes of research concerned with childhood cognitive development. His research, performed largely by individual observation, has become popular during the past few years 79 in the field of educational psychology. Although quite at odds with

Au&ubel's theory in some respects, some parallelisms can be drawn between the two theories.

Piaget describes two complementary processes of cognitive development. Cognitive acts are seen as organization (internal) of and adaptation (external) to the perceived environment. Piaget believes intellectual activity and biological activity are hoth part of an overall process by which an individual organizes experience and adapts to the environment

Four basic concepts relate to the processes of organization and adaptation. These are schemata, assimilation, accomodation, and equilibrium.

Schemata are conceived as cognitive structures--the mental counter-part of biological structures—which the individual uses to adapt to and organize his environment. Schemata are used to process incoming stimuli. As the child develops, schemata are thought to broaden and become more generalized. They become differentiated.

The process by which schemata change is called adaptation. Adapt­ ation, in turn is defined by two processes, assimilation and accomod­ ation.

Assimilation, in Piagetian terms, is a cognitive process by which the individual integrates new information (perceptual matter or stimulus events) into existing schemata. Assimilation is thought to occur continually and theoretically results in growth but not change of schemata (quite opposed to Ausubel's view). Piaget explains changes of schemata in terms of accomodation. 80

If no schemata are available into which new information can be

assimilated, new schemata must be created or existing schemata must

be modified. Piaget refers to both of these processes as accommod­

ation. In assimilation, available structure is imposed on new stimuli.

In accommodation, schemata are changed to f it the new stimuli.

Assimilation results in growth (quantitative change of knowledge);

accommodation results in development (.qualitative change in know­

ledge) .

In order for a person to detect differences among ideas and to

generalize (to balance assimilation and accommodation), a mediating

process called equilibration occurs. Disequilibrium between assimi­

lation and accommodation is thought to be the motivating factor which

brings about equilibration through additional assimilation or accomm­

odation.

As the child's development occurs, schemata are organized into

higher order structures called operations. Adding, classifying, and

conserving mass are examples of higher order structures called oper­

ations. Piaget uses these logicomathematical structures rather than

language to explain how experiences are represented and related

internally.

The Piagetian model suggests that mental mechanisms are different

at each stage of development and that qualitative differences in these mechanisms are indicative of intellectual structure during a given

period of time. Piaget believes that each individual passes through

various intellectual stages, and that identification of these stages

is useful in determining what the individual can learn. This flies in 81

opposition to the traditional paridigm which maintains that intellec­

tual development is a function of the individual's experience and

that learning determines the individual's development. The Piagetian

model states, in essence, that intellectual development determines what can be learned. Piaget rejects the idea that cognitive struct­

ures (schemata) can be induced directly as a substitute for general

experience. Experience is divided into two types: physical, assoc­

iated with early stages of development, and logical-mathematical, associated with the formation of structures (schemata) of the mind.

Piaget rejects the notion that extrinsic forces are responsible for motivating the cognitive behavior of an individual, and consequent­

ly he also rejects the concept of reinforcement from behaviorist learning theory. According to Piaget, the primary motivating force for cognitive activity is the process of assimilation.

Piaget classifies intellectual development into four main stages.

The four stages are: sensory-motor, preoperational, operational, and formal. The individual is thought to progress through these stages in a sequential manner, from birth through maturity. Each stage is qualitatively different, yet each succeeding stage is hierarchical and dependent upon preceding stages. Although age levels are suggest­ ed for each stage, transition from one stage to the next is not considered to be abrupt or absolute.

The stage of sensori-motor intelligence begins at birth and continues until about age two. During this time, behavior is primarily motor. Innate reflexes begin to function. As an active organism, the child interacts with the environment with his senses 82

and muscles. At the beginning of this stage, the child does not

differentiate objects from self. Near the end of this stage, the child

recognizes that objects exist separate from self and may move in

space. The child can reproduce from memory, use mental symbols, and

refer to objects not present.

The stage of preoperational thought occurs between two and seven years of age. It is called preoperational because the child is not yet able to carry on logical operations such as addition, subtraction,

placing in order, substituting one entity for another, or reversing

subclasses and classes. During this time operations are infra!ogical

and include such things as observing, measuring, quantifying, relating

to time frames (past, present, and future), seriating, classifying,

relating to space, counting objects, and establishing values. These

infralogical operations are considered fundamental to logical oper­ ations which occur at the next stage. Completely logical or "adult-

like" thought is thought to he inhibited at this stage due to the

accompanying characteristics of egocentrism (everybody thinks the same way I do; there is no need to question my thoughts), centration

(tendency to focus on one aspect of a stimulus rather than all

aspects), irreversibility (inability to reverse operations or follow a line of reasoning back to its starting point), and the inability to follow transformations (inability to follow the elements of a sequence or successive states).

The single most important development during the preoperational stage is the development of language. Language is believed to

internalize behavior symbolically, and speed up the rate at which 83

experience can take place. Language permits thought and adaptation

beyond the individual's immediate actions and environment. Whereas

sensori-motor intelligence proceeds in a one-step-at-a-time fashion,

representational thought and language permit the child to handle many

elements in an organized manner (Piaget & Inhelder, 1969, p. 86).

A key question asked by cognitive psychologists is whether

language precedes and determines logical thought, or whether logical

thought determines language. Piaget and Inhelder (p. 88) suggest

that language is neither necessary nor a sufficient condition to

ensure logical thought, although it clearly acts as a facilitator.

They cite the cognitive functioning of deaf-mutes in support of their

contention. In contrast, Ausubel (1978), Chomsky (1972), Vygotsky

(1962), and Whorf (1956) place great emphasis on language development

as the primary vehicle for higher-order cognitive functioning.

The concrete operational stage occurs between ages seven and

eleven. This stage is called concrete because the child's thought

is restricted to what can be encountered in direct experience. During

this stage, children develop mental operations such as classifying,

one-to-one correspondence, reversing thought processes, performing mathematical operations such as adding, subtracting, substituting, multiplying, dividing, and ordering elements or events in time. The

child is less stimulus bound, relying less on perception and more on

cognitive activity. Concepts of conservation--substance, number, continuous quantity, length, area, weight, volume displacement—dev­ elop during this period. Improved concepts of causality, space, time,

ans speed evolve. Egocentrism is diminished by socialization. 84

Centration diminishes. Functional understanding of transformations is attained, and concrete operational thought is reversible.

The period of formal operations occurs between ages eleven and fifteen. At this stage, reasoning is systematic and involves logically complex processes. Operations are not restricted to use solely on concrete objects. Formal operations are characterized by scientific reasoning and hypothesis building (testing). The formal operational individual can perform the following operations which the preoperational individual could not: combinatorial thought (testing all possible combinations of ideas), complex verbal problems

(syllogisms), proportions, conservation of movement, and hypothetical problems. Piaget believes individuals reach maximum qualitative development by about age 15. Their predominant mental activity at this age is formal, although all four types of behavior are exhibited on occasion.

Industrial Arts Curriculum Project

In 1965, a federally-funded curriculum effort entitled the

Industrial Arts Curriculum Project (IACP) was initiated. One of the major purposes of the project was "to develop a rationale to guide the conceptualization of a more adequate structure or framework for the organized study of industry" (Towers, et al., 1966, p.v.).

The project staff consisted of professional industrial arts theorists and specialists from a broad spectrum of the university community. In addition, the staff received assistance from a national advisory committee and a task force composed of persons 85 representing a hroad spectrum of disciplines and specialties. Exper­ tise was drawn from the fields of philosophy, history, sociology, economics, education, and a variety of industrial specialists representing such substantive fields as industrial design, industrial engineering, industrial psychology, and industrial organization and management.

As a result of extensive analysis of knowledge classification schemes and institutionalized practices, the project identified industrial technology as the knowledge base for industrial arts.

Finding that no existing knowledge classification scheme provided an adequate structure of industrial technology, the project undertook the conceptualization of a more adequate structure to be used for instructional purposes. Three criteria guided this conceptualization.

The structure should:

1. include all practices which affect humans and materials

2. have mutually exclusive subcategories

3. be operationally adequate for instruct­ ional purposes, (p. 78)

IACP described the dominant function of industry as "organizing resources {management} and of substantially changing their form

{production} so that they yield the industrial material goods required to satisfy man's wants" (p. 148). IACP also recognized that management and production practices affect humans as well as things.

As a result of further analysis, a hierarchical structure of industrial technology knowledge was devised. This structure is represented in Figure 3 (Towers, et a l., 1966, p. 167). Essentially, Industrial Technology

Industrial Management Industrial Production Industrial Personnel Technology Technology Technology

Industrial Material Goods

Construction Technology Manufacturing Technology

Construction Construction Construction Manufacturing Manufacturing Manufacturing Management Production Personnel Management Production Personnel Technology Technology Technology Technology Technology Technology

Constructed Manufactured Material Goods Material Goods

Figure 3. Major Structural Elements in Industrial Technology (Towers, et a l., 1966, p. 167) 87

this figure shows three subelements of industrial technology: indust­

rial management technology, industrial production technology, and

industrial personnel technology. These three subelements, in turn, are related to two broad types of material goods: constructed goods which are produced on a site and manufactured goods which are prod­ uced in a plant.

Each of the three subelements of industrial technology was further taxonomized by the project. Manufacturing technology, the taxonomy from which the advance organizer was developed for this exper­ iment, was further taxonomized, in some instances to a fifth level of specificity (Towers, et a l., 1966, pp. 176-192). The next subordinate level in the taxonony contained three elements: pre-processing, processing, and post-processing (see Fig. 4). Processing, the element from which the advance organizers in this study were developed, cont­ ained three subelements: separating, combining and forming.

The completed taxonony of industrial technology was used by IACP as a basis for selecting instructional activities and generating instructional units for two full-year courses of study. A variety of means were used to, at least implicitly, present a hierarchy of concepts. Two such means were graphic displays and reading order.

Although explicitly identified advanced organizers were not included in the IACP instructional packages, i t was conceived that the use of advance organizers could facilitate learning of the broad spectrum of knowledge included in the IACP and similar instructional packages. MANUFACTURING TECHNOLOGY

MANAGEMENT PRODUCTION PERSONNEL TECHNOLOGY TECHNOLOGY TECHNOLOGY

PREPROCESSING PROCESSING POSTPROCESSING

FORMING SEPARATING COMBINING

Figure 4 . Elements of Manufacturing Technology 89

Summary

This chapter has been organized into eight sections. They involved: Ausubel's theory in context, the elements of Ausuhel's theory, a review of literature reviews relating to advance organizer research, the research procedure meta-analysis, two metaanalyses of advance organizer research, organizer format, advance organizer research in industrial arts, the Wisconsin Model, Piaget's theory, and the Industrial Arts Curriculum Project taxonomy which was used as a basis for developing the advance organizer for this study.

Ausubel's concept of reception-discovery and rote-meaningful continua was reviewed, along with the principal role played by each type of learning at various levels. Representational, concept, and propositional learning were discussed as was Ausubel's distinction between concept formation and concept assimilation. Three levels of propositional learning (subsumptive, superordinate, and combinat­ ional) and implications for each type of learning were described.

Two major principles, progressive differentiation and integrative reconciliation, were described in order to explain Ausubel's concept of anchorage, as well as to provide operational guidance for the development of an advance organizer for the study. Ausubel's concepts of dissociability strength and meaningful forgetting were reviewed to provide background for explaining retention. Ausubel's general description and rationale for using advance organizers was presented.

Widely quoted reviews of advance-organizer research were reviewed in order to represent the tenor of discussion about Ausubel's theory and to identify variables and approaches suggested for future research. 90

Two meta-analyses were reviewed in order to identify the mult­

itude of variables considered in previous advance organizer research

and to provide a quantitative analysis of the relative effects of

these variables. Additional studies which used other than prose

advance organizers were reviewed to supplement the information

provided by the meta-analyses.

The Wisconsin Model of Learning and Piaget's model of cognitive

development were reviewed as two contemporary viewpoints of cognitive

processing. Finally, a summary of pertinent aspects of the rationale

developed by the Industrial Arts Curriculum Project was presented to

provide background on the organization of the advance organizers

used in this study.

The next chapter will describe the pilot study and the develop­ ment of the stimulus materials and criterion examination used in

this study. The experimental design and hypotheses will be presented,

as will instructional procedures, the sequence of treatment and measurement, and a description of data collection and analysis

procedures. CHAPTER III

THE DESIGN OF THE STUDY

This chapter presents the experimental design of the study.

It deals with the research methods and procedures, including a description of the pilot study. In order to present this information, the chapter is organized into the following sections: (1) pilot study, (2) stimulus materials, (3) criterion examination, (4) exper­ imental design, (5) hypotheses, (6) sample description, (7) instruct­ ional procedures, (8) sequence of treatment and measurement, and

(9) data collection and analysis.

Pilot Study

Pre-pilot and pilot studies were conducted to develop and test the instructional materials, tests, and experimental procedures.

Informal pre-pilot tria ls were conducted with 12 eighth-grade students enrolled in industrial arts classes at Price Laboratory

School, Cedar Falls, Iowa. The pilot study was conducted with 110 eighth-grade industrial arts students enrolled in the two Cedar Falls junior-high schools. Two junior-high teachers conducted the pilot study.

91 92

The pilot study was conducted for several reasons. These reasons were:

1. To test and improve instructional procedures

(introductory statements, timing, physical

arrangements, teacher preparation, etc.).

2. To determine time requirements for various

instructional and testing phases.

3. To determine the suitability of video tapes

and readings for presentation to the

targeted group of students.

4. To develop a test instrument with suitable

discriminability and reliability.

5. To provide experience upon which difficulties

during the actual experiment might be

anticipated and avoided.

Several changes were made on the basis of information gathered from the pilot study. The introductory statements which had been prepared for introducing the video tapes and readings to students were shortened. The video tapes were shortened from about 15 minutes duration to about 10 minutes each. Further work was done on reducing the readability level of the reading passages. (Procedures for determining readability are reported in the stimulus materials section.) Additional test items were generated and several items were revised to produce two longer forms of the test.

The revised test forms were administered to the pilot group as a retention test one week after the instructional period to obtain 93

new item analyses, discriminability indexes, and reliability

coefficients. Improvements in the procedures, instructional

materials, and tests permitted the actual experiment to proceed

without any complications.

Stimulus Materials*

Three sets of stimulus materials were developed for this

experiment. They were: (1) two advance organizer video tapes,

(2) two conventional overview video tapes, and (3) two printed

learning passages.

Modes of presentation. The video-tape mode of presentation was chosen for the following reasons: (1) to provide a measure of

control so that each group received as nearly an identical set of

stimuli as possible, (2) to allow for presentation of the material

in both aural and vislual forms, (3) to fa c ilita te the presentation of several material-processing demonstrations, and (4) to provide

for variety in the overall instructional sequence.

The printed model of the learning passages, likewise, provided

for control over the stimuli presented to each group. In addition,

the printed materials used in the experiment were designed to be

representative of typical text materials used in industrial arts

classes. A number of illustrations from commercial textbooks were

* Complete transcripts of the stimulus materials are found in the appendixes in the following order: Appendix A, Advance Organizer I; Appendix B, Advance Organizer II; Appendix C, Conventional Overview I; Appendix D, Conventional Overview II; Appendix E, Learning Passage I; Appendix F, Learning Passage II. 94

used to make the readings easier to understand and more like typical

textbook materials. Permission was obtained from affected publishers

to reproduce the illustrations.

Advance organizer development. A central attribute of an

advance organizer is its hierarchical nature. As defined in Chapter

I, an advance organizer is a generalized model which f ir s t subsumes all general classes, then various subclasses, and finally specific

ideas.

As noted in the Review of Literature, the Industrial Arts

Curriculum Project devoted an extensive amount of effort to identify­ ing and classifying the elements of industrial technology. Three major branches of industrial technology were taxonomized: management technology, production technology, and personnel technology. These major concepts served as a basis for generating two instructional packages for year-long courses in construction and manufacturing.

The advance organizers for this study were developed from part of the IACP production technology taxonomy of manufacturing. The specific focus was on material processing by forming, separating, and combining processes. These three subelements are further classified in a block diagram in one of the IACP instructional texts, The World of Manufacturing (Lux & Ray, 1971, p. 306). This diagram is shown in Figure 5.

The IACP taxonomy was modified slightly to eliminate the "other processes" category shown as a subelement of "separating" in Figure

5. As shown in Figure 6, the separating category was reclassified into two subelements: direct-separating and nondirect separating. STANDARD STOCK

FORMING SEPARATING Casti ng Shearing or molding Compressing Chip removing or stretching

Conditioning Other processes

COMPONENTS I COMBINING Mixing Coating Bonding

Mechanical fastening

SUBASSEMBLIES and FINAL ASSEMBLIES

Figure 5. Subelements of Processing (Lux & Ray, 1971, p. 306) 96

MATERIAL PROCESSING

FORMING COMBININGSEPARATING

DIRECT SEPARATING MIXING

CASTING or MOLDING — Shearing

COATING — Chip Removing

COMPRESSING or STRETCHING NONDIRECT SEPARATING BONDING

CONDITIONING — Fracturing MECHANICAL FASTENING Agent Separating

Figure 6. Modified Subelements of Processing Used as a Basis for the Advance Organizer 97

The category "direct separating" was used to describe processes where a solid tool directly removed material from the workpiece. The category "non-direct separating" was used to describe processes which cause materials to break in a controlled manner or which use an agent such as a flame or a chemical.

All three types of processes (forming, separating, and combin­ ing) were included in the advance organizers as a way of representing the entire universe of material processing, and also as a way of presenting and contrasting the attributes of each type of process.

The organizer was divided into two parts in order to keep the length of each presentation suitable for the intended audience. This divis­ ion also provided for repetition and review of some of the proposit­ ions. Transcripts and other graphic representations of the advance organizers are shown in Appendixes A and B.

The first part of the organizer presented an overview of all three types of processes, and then explained forming processes in detail. The second part of the organizer explained separating and combining processes in detail and recapitulated an overview of the entire scheme.

Five kinds of information are used to present each concept in the organizer. First, a block diagram was used to present the hierarchical relationship of concept and subconcepts (attributes).

A narrative was presented aurally to explain the block diagram.

Second, each concept was defined, using an aural narrative and a visual. Third, a simple demonstration was used to illu strate the concept at a simplified level. Fourth, an industrial process was 98 demonstrated as an example of the concept. Finally, the concept was reviewed and related to the hierarchical block diagram.

Conventional overviews. Video tapes called conventional overviews were developed and administered as one treatment level in order to keep the length of time and type of instruction for each level as similar as possible. Transcripts of the conventional over­ views are found in Appendixes C and D.

The conventional overviews contained a series of demonstrations of industrial processes as they are typically demonstrated in an industrial arts class. Each type of process used as an exemplar in an advance organizer video tape was also used in a conventional overview. The advance organizer tapes presented specific examples of processes in a sequence which was compatible with the introduction of the hierarchical concepts. In contrast, processes shown in the conventional overview were shown in random order.

Each process used in the conventional overview was identified and introduced using a chart with the name of the process on it.

Each process was described orally as the demonstration was performed.

Terms were used at very specific levels and were focused on the specific process being demonstrated rather than on groups of related processes.

Learning Passages. Two sets of text-like readings (see Append­ ixes E and F) were developed for use as the main learning task in this experiment. The passages were designed to provide specific examples of processes which could logically be subordinate elements of the more abstract advance organizer. In addition to segments specific types of processes, sections on polymers and metals were added which were potentially relatable to material conditioning, part of forming. The passages were developed using the following criteria:

1. A sample of specific processes for each

major group of processes listed on the

advance organizer was included.

2. Process terminology was used in a very

specific sense and at a lower level of

abstraction and inclusiveness than term­

inology used for the advance organizers.

3. The learning passages did not replicate

materials which had already been studied

by the target experimental group.

4. The arrangement of topics within the

learning passages was random so that the

organization of the learning passage was

not the same as the advance organizer.

5. Readability level was appropriate for the

target experimental groups.

6. The length of each learning passage was

such that it could be studied by almost all

students within twenty to twenty-five minutes.

7. Illustrations were used to clarify the

reading and add interest. 100

The processes described in the first reading were related to

the principal part of the first advance organizer. The second

reading contained specific processes related to the second advance

organizer.

Other than this grouping which was designed to be potentially

interactive with the advance organizer, no mention was made in the

readings about the relatedness of the various processes.

As a precauation against presenting material which subjects would be familiar with, processes using equipment such as extrusion machines, punch presses, and other large pieces of equipment not normally found in a junior-high laboratory were selected when possible.

As another precaution, students were asked to respond to each section of the readings regarding their familiarity with the material after pilot tests were administered.

Content validity. A jury was used to analyze the accuracy and content validity of the learning passages. Four people provided

independent comments on the learning passages. Three of the four,

Dr. James LaRue, Dr. Douglas Pine, and Dr. Gary Browning, were faculty members of the Department of Industrial Technology at the

University of Northern Iowa. Each person was a specialist in prod­ uction. A fourth member, Mr. Lyle Madson, was an industrial engineer at the John Deere Research and Development Center, Waterloo,

Iowa. No challenges to the accuracy or validity of the material were made. The jury reviewed the material again after readability revisions.

Again, no challenges were made. 101

Readability. The learning passages were analyzed for read­

ability using the computer program STAR (Wilhelm, no date). This

program was originally developed by General Motors Corporation to

evaluate the readability levels of technical manuals. The program

used for this analysis was a revised edition provided by the Grant

Wood Area Education Agency, Cedar Rapids, Iowa.

In addition to providing readability measures, the program

listed what were called "Hi-Cal" words—difficult words which tended to raise the readability level of each sample. This provided infor­ mation which was useful for lowering the readability levels where needed.

Analysis of the final revision of the f ir s t reading passage provided the following average measures for the entire reading: average sentence length, 9.3 words; Flesch Index, 73.7 (judged to be

"fairly easy," a step easier than "standard" writing found in digests); grade level equivalent, 7.86; Dale Index, 7.6; and Fog

Index, 8.0.

Analysis of the final revision of the second reading passage provided the following average measures for the entire reading: average sentence length, 11.82 words; Flesch Index, 73.66 (very close to the Flesch Index for the f ir s t reading); grade level equivalent

7.89; Dale Index, 7.64; and Fog Index, 7.90.

Readability of the learning passages was also examined in another way. As the passages were developed, they were reviewed by

Dr. James Albrecht and Mrs. Linda Christensen, specialists in English composition and reading, respectively. The readings were examined 102 for organization, fluency, clarity, and the reviewers' judgements

relative to the reading difficulty. In general, two kinds of comments

were made. In some instances words judged to be at a lower vocabulary

level were substituted. In other instances, additions were made to

help clarify the concepts which were presented. Both of these people were relatively naive about the subject matter presented in the

readings. As such, they brought a different perspective to the review

than was brought by industrial arts specialists who reviewed the

readings as part of a content validity analysis.

The length of each passage was such that slower reading students

could complete reading the material in twenty minutes. The topic

headings included in the f ir s t reading were: polymers, injection molding, extrusion, metals, forging, heat treating, and presswork.

The topic headings for the second reading were: arc welding, gas welding, brazing and soldering, flame cutting, drawing, gluing,

the lathe, drilling, threaded fasteners, milling, and grinding.

A number of typical illustrations were selected from standard textbooks to illustrate the processes explained in the text matter.

Finally, in order to improve the appearance of the materials and reduce the number of pages (which created a negative f ir s t

impression with students during a pre-pilot study), the reading passages were phototype-set and reproduced by offset printing.

Criterion Examination

In a ll, six versions of a multiple-choice test were developed during this study. The firs t four versions were developed during the 103 pilot studies; the last two versions were used as an initial learning test and a retention test. The retention test used the same questions as the initial learning test in a rearranged order. The final versions of the test had 58 questions, each having four alternative responses.

The test was used as a power test with no time lim it imposed on students.

Test questions were developed from the reading passages using the following criteria:

1. A proportional number of questions were

developed for each section of the reading.

The proportion related to the length of each

passage in words.

2. Test items were developed which did the

following:

a. defined or related the attributes of

a process to the process name,

b. identified potential uses for a given

process,

c. involved selecting one process over

another to change material in a given

way,

d. identified the properties of a given

material, or

e. described what happens to a material

during a given process. 104

Dr. Bruce Rogers, a test and measurement specialist at the

University of Northern Iowa, reviewed initial test items as well as

revised test items for readability and appropriate construction.

The jury panel used to validate the reading material content was also used to validate answers and provide suggestions for test items. Dr. Rogers and this jury were also used to compare test

items against the advance organizer and to assure that the advance organizer did not specifically answer any test items.

Responses for each version of the test were submitted to the

Institutional Research Testing Service at the University of Northern

Iowa for a computerized item analysis. The computer printout provided information on item difficulty and discriminability, as well as

Kuder-Richardson 20 reliab ility estimates and other descriptive statistic s. These data were used to revise and improve the test.

The last pilot-tested version of the test was taken as a retention test by 75 students at Peet Junior High School in Cedar

Falls. Twenty-two percent of the test items had a difficulty index for which less than 30 percent of the students responded correctly;

71 percent of the questions were of average difficulty (30% to 70% correct student responses); and 8 percent were of low difficulty

(more than 70% of class answered correctly).

Thirty-five percent of the questions had high item discrimination

(more than .40); 27 percent had moderate discrimination (.30 through

.40); 16 percent had low discrimination (.20 to .30); and 22 percent had low discrimination (less than .20). The mean score was 22.24 105 with a standard deviation of 7.02. The Kuder-Richardson KR-20 reliability coefficient was .79. Parallel items from a previous test with higher discriminability levels were substituted for low discrim­ ination items on this test as a means of improving the test before using it in the experimental study. A copy of the final version is included in Appendix G. Experimental test data are reported in

Chapter IV.

Experimental Design

It was necessary to carry out this experiment using intact classes. Kennedy (1977) describes hierarchical (nested) and partial hierarchical designs as being particularly appropriate for experiments which must be conducted with multiple intact classes. Kennedy states:

Hierarchical and partially hierarchical arrangements are among the more interesting and useful designs .... Further, they are tailor-made for educational research. Educat­ ional researchers frequently find themselves working in schools, experimenting with classrooms within these schools, and relying on the cooperation of teachers to implement experimental interventions. Further, educat­ ors know that there are differences among schools, classrooms, and teachers and therefore it is desirable to attempt to control or account for these real aforement­ ioned differences. Unlike the experimental psychologist working with rats in a labora­ tory, or the agricultural researcher employed by an experimental station, educational researchers often find that they are greatly restricted in their ability to use known and proven control techniques. Specifically, they frequently are not able to randomly assign students to different treatment conditions and are not permitted to organize groups of 106

students to completely satisfy the require­ ments of conventional statistical models. (p. 490)

An alternative . . . is to nest classrooms, or schools within levels of the instructional variable. By doing this, the unique effects of classrooms (or schools) can be statistically estimated and thus controlled, (p. 57)

A partial hierarchical design, One Between-Groups and One

Within-Subjects, was selected for this experiment. This design

incorporates a fixed variable A (independent variable), randomly assigned B^ variables (classes) nested within levels of A, and subjects

nested within levels of IB. Variable £_ (the dependent variable)

is added to the hierarchical arrangement and provides the within- subjects measure. Variable C involved two measures; an initial learning measure (C^) administered after treatment, and a retention measure (C2) administered three weeks later. A data matrix for the design is shown in Table 7. The matrix depicts two levels of the fixed instructional treatment variable A: one level for an advance organizer treatment (A^); the other level for a conventional overview treatment (A 2). Ten randomly-assigned intact classes (groups) constitute variable ^ which are nested within A. For purposes of clarity, groups B12 through B ^ and groups B22 through B2^ are represented by ellipses. Subjects within classes constitute the next variable S^. They are nested within levels of B_. Students from the f ir s t student in each group through the nth student are represented by ellipses. Finally, variable C^, student scores on the initial learn­ ing and retention tests, completes the model. Table 7. Data Matrix for One Between-Groups and One Within-Subjects Design (Kennedy, p. 539; Modified for Present Study)

*111 vllll 1112 *11 nil n lll nll2

1151 115 1152 *15 nl5 nl51 nl52

*121 X1211 1212 B 21 n21 n211 n212

*125 1251 1252

25 n25 n251 n252

-Treatment B--Intact S—Students X—Initial Test X—Retention Level Cl asses Score Score 108

The Null Hypotheses

The hypotheses tested with this experimental design, as stated

in the null form, were:

Ho^ There is no significant difference in initial learning

between the advance organizer group and the conventional overview

group as measured by the criterion test.

H02: There is no significant difference in retention between

the advance organizer group and the conventional overview group as

measured by the criterion test when administered three weeks after

the initial learning test.

The .05 probability level was chosen as the basis for rejecting

or failing to reject the null hypotheses.

Sample Description

The subjects used for this experiment were eighth- and ninth-

grade students enrolled in industrial arts classes at Roosevelt and

McKinley Junior High Schools in Cedar Rapids, Iowa. As such, the

experimental sample was drawn from two out of six junior high schools

in the city school system.

The two schools were chosen for the experiment on the basis of the following conditions:

1. Administrators were willing to permit classes

to participate in the experiment.

2. Teachers volunteered to carry out the

experiment in their classes. 109

3. The curriculum in these two schools did

not reflect use of the organizer concepts

used as the experimental treatment.

4. Analysis of the industrial arts curriculum

in each school indicated that concepts used

in the conventional overview and reading

materials were not already systematically

taught to the classes selected for the

experiment.

5. A sufficiently large group of students was

available for the experiment.

Ten intact classes were used in the experiment; six at Roosevelt

and four at McKinley. Classes used for the study were enrolled in three different courses: woods and plastics, graphic arts, and manufacturing. Classes were stratified by course and by school before randomly assigning treatments. Therefore, each of the two graphic arts classes received a different treatment; each of the two manufacturing classes received a different treatment; and an equal number of woods and plastics classes for each school received a different treatment.

Class sizes ranged from 16 to 24, with a mean enrollment of

20.2. All classes were elective and offered to both eighth and ninth

graders. The mixtures of eighth and ninth graders appeared to occur

by chance; therefore, there did not appear to be any systematic

scheduling of any particular group into any particular industrial

arts class. High and low groupings in mathematics and language arts 110

classes may have affected industrial arts enrollments, but in all

cases, at least half of the students in the high and low groupings

for these two tracks had the opportunity to elect an industrial arts

course. The average overall enrollment in sample classes was about

50 percent 8th graders and 50 percent 9th graders.

A few girls were enrolled, but the overall class enrollment was

predominantly male--about 90 percent. Several minority students were enrolled, but overall minority enrollment averaged only 5.5 percent. Table 8 shows the characteristics of each class.

Specific data regarding individual achievement and I.Q. scores of subjects used in the experiment were not available to the experimenter, nor were data about socio-economic level, occupational status, or other demographic data.

Instructional Procedures

Three teachers were involved with the administration of the stimulus materials and criterion tests: two at Roosevelt Junior

High and one at McKinley Junior High.

An orientation session was held with each teacher on the Friday before the week of the experiment. The sequence of the experiment was reviewed, video tape machines were set up and checked out, and general instructions for administering each segment of the experiment were discussed.

Each teacher was provided with a labeled folder for each instructional period in which his class participated in the experiment.

The folder was used to file test answer sheets as well as attendance Table 8. Characteristics of Classes in the Experimental Sample

Class 8th Grade 9th Grade Female Minority School No. Students N % N % N % N %

Roosevelt 1 18 4 22 14 78 1 5.6 1 5.6 Roosevelt 2 20 9 45 11 55 3 15.0 0 .0 Roosevelt 3 19 14 74 5 26 1 5.3 1 5.3 McKinley 4 22 8 36 14 64 2 9.1 0 .0 McKinley 5 23 16 70 7 30 1 4.4 4 17.4 Advance Organizer 102 51 50 51 50 8 7.8 6 5.9

Roosevelt 6 24 11 46 13 54 4 16.7 1 4.2 Roosevelt 7 22 9 41 13 49 4 18.2 0 .0 Roosevelt 8 18 14 78 4 22 3 16.7 0 .0 McKi nley 9 20 12 60 8 40 2 10.0 3 15.0 McKinley 10 16 7 35 9 65 0 .0 1 6.3 Conventional Overview 100 53 53 47 47 13 13.0 5 5.0

GRAND TOTAL 202 104 51 98 48 21 10.0 11 5.4 112

reports and comments about any unusual occurrances during experimental

treatments and testing. Answer sheets were coded by teacher, class

hour, grade level, student number, and test form number. Each student

received a 3 x 5 card with his/her coded number for use as insurance

against errors in coding and recording information on answer sheet.

Sequence of Treatment and Measurement

Figure 7 shows the general sequence of treatment and measure­ ment for each group. Reading from le ft to right, the top row of boxes depicts the sequence of stimuli presentations for the advance- organizer group. The bottom row of boxes depicts the stimuli sequence for the conventional-overview group. The experimental stim­ ulus materials were administered during the first part of each class period. The last part of each class period was reserved for laboratory activities which were a part of the regular non-experimental curric­ ulum. Advance organizers and conventional overviews were administered a day in advance of the learning task in order to keep formal verbal

instruction on any given day to less than 25 minutes which was considered the maximum interest span of students for this type of

instruction.

It should be noted that Dawson (1965, pp. 65-67), in consul­ tation with Dr. Ausubel, found that administration of the advance organizer immediately prior to the learning task—as has been custom­ ary in most advance organizer studies--had an inhibiting effect on

learning. He, therefore, administered the advance organizer one day

in advance of the learning task. Dawson's study was one of the few to Day 1 Day 2 Day 3 Day 4 Day 5

Advance Readi ng Advance Readi ng Achievement Organizer No Organizer No Test Video-tape I Video-tape II I I II (initial learning)

Conventional Reading Conventional Reading Achievement Overview No Overview No Test Video-tape I Video-tape II I I II (initial learning)

Figure 7. Sequence of Treatment and Measurement Note: Class periods in the experimental schools were from 50 to 55 minutes in length. It was anticipated that each treatment and measurement (video tape I, reading I, etc.) would require approximately one-half of the class period. The remainder of each class period was devoted to "hands-on" activities which were a part of the curriculum for that class. A reordered version of the achievement test was administered as a retention test three weeks after the treatment and measurement phase shown in the above figure. Table 9. Classes by Randomly-Assigned Treatment

Advance Organizer Treatment

Class No. Class Period Class Name Teacher School

1 1 Graphic Arts Archibald Roosevelt 2 4 Wood & Plastics Schultz Roosevelt 3 6 Wood & Plastics Schultz Roosevelt 4 4 Manufacturing Turner McKinley 5 6 Wood & Plastics Turner McKinley

Conventional Overview Treatment

Class No. Class Period Class Name Teacher School

6 3 Graphic Arts Archibald Roosevelt 7 5 Wood & Plastics Schultz Roosevelt 8 7 Wood & Plastics Schultz Roosevelt 9 2 Manufacturing Turner McKi nley 10 3 Wood & Plastics Turner McKinley 115 use 'industrial arts content. He demonstrated that his advance organ­ izer was significantly facilitative.

Treatment levels were randomly assigned to classes as noted in

Table 9. Each part of the instructional sequence and testing was done on the same day for each class.

Data Collection and Analysis

The researcher-developed achievement test was administered twice: once at the end of the instructional phase as an initial learning test and again three weeks later as a retention test. The test was administered as a power test. No time lim it was imposed on students.

The test took about twenty-five minutes to complete.

Test results from students who were absent or late for class during any part of the instructional period were not used in the analysis of data for the study. Student raw score data were analyzed employing analysis of variance as the statistical treatment. A model summary of the statistical analysis is shown in Table 10.

Summary

Chapter III has presented a description of the pilot study and how the stimulus materials and criterion examination were developed.

The experimental design for the study and the null hypotheses were presented. Instructional procedures, the treatment and measurement sequence, and data collection and analysis procedures were described. Table 10. Surranary Table for One Between-Groups and One Within-Subjects Design (Kennedy, p. 543)

Source df SS EMS F

Between Ss abn-1 Eq* (10.49) Between Groups ab-1 Eq. (10.50) A a-1 Eq. (10.51) E + S/B/A + B/A + A MS (A)/MS (B/A) B/A a(b-l) Eq. (10.52) E + S/B/A + B/A MS(B/A)/MS(S/B/A) Within Groups ab(n-l) Eq. (10.53) CO o LO U r o l • S/B/A ab(n-l) I E + S/B/A

Within Subjects abn(c-l)

C c-1 Eq. (10.54) E + SC/B/A + BC/A + C MS(C)/MS(BC/A) AC (a-l)(c-l) Eq. (10.55) E + SC/B/A + BC/A + AC MS(AC)/MS(BC/A) BC/A a(b-l)(c-1) Eq. (10.56) E + SC/B/A + BC/A MS(BC/A)/MS(SC/B/A) SC/B/A ab(c-l)(n-l) Eq. (10.57) E + SC/B/A

Total abcn-1 Eq. (10.48)

♦Equations: See Kennedy, pp. 542-548. 117

Chapter IV will present an overview of test data and will describe the analysis of the data by analysis of variance. Findings related to the rejection or failure to reject the null hypotheses of the study will be reported. A discussion will be presented relative to the outcomes of the experiment. CHAPTER IV

ANALYSIS OF DATA

This chapter presents an analysis of the data obtained in the experiment. It includes a record of test scores and frequency polygons showing class score distributions. Overall frequency d ist­ ributions for each treatment are included in Appendix H.

This chapter is organized into the following sections:

(1) overview of test data, (2) analysis of variance, (3) hypothesis testing, and (4) discussion.

Overview of Criterion Test Data

The test scores collected from the experiment were analyzed according to item difficulty and discrimination. The results of these analyses are shown in Tables 11 and 12. In general, difficulty levels were quite acceptable, with 76 to 90 percent of the items in the "average" difficulty range. The tests were highly discrimin- inating with from 40 to 60 percent of the items in the high range.

Table 13 shows standard test characteristics for the initial learning and retention tests which were administered to both treatment

118 119 groups in this experiment. The reliab ility coefficients (.85 to

.90) are quite acceptable in terms of standard practice (.70 or above).

A casual comparison of mean scores for the two treatment levels, as shown in Table 14, indicates that there was very l ittl e difference between levels on both tests. The mean score on the init­ ial test for the advance-organizer treatment was 29.91, as compared with the mean score of the conventional-overview treatment of

28.93—siightly less than 1 point difference. On the retention measure, the mean score for the advance organizer treatment was

26.66, as compared to 26.07 for the conventional overview treatment.

The difference was even less than the difference between initial test means.

As expected, retention scores declined from initial measure­ ments. A slightly greater decline occurred for the advance organizer treatment (29.91 to 26.66 or 3.25 points) than occurred for the conventional overview treatment (28.93 to 26.07 or 2.86 points).

Looking at individual class means, (see Table 14) wide ranges occurred among groups within each treatment level. The range for the advance organizer group means on the initial test was from 26.19 to

34.75 (8.56 points). The range for the conventional overview means on the initial test was 25.53 to 32.38 (6.85 points). On the reten­ tion test, the range for the advance organizer treatment was 19.09 to 30.30 (11.21 points). The range on the retention test for the conventional overview treatment was 17.79 to 32.00 (14.21 points). 120

Table 11. Difficulty Levels for Test Items

TEST Percentage Low Average High (more than .70) (.30 through .70) (less than .30)

Initial Test

Advance Organizer 10 83 7

Conventional Overview 14 76 10

Retention Test

Advance Organizer 0 90 10

Conventional Overview 2 81 17

Table 12. Item Discrimination

TEST Percentage Marginal Low Moderate High (less than .20) (.20-.30)(.30-.40) (more than.40)

Initial Test

Advance Organizer 14 12 17 57

Conventional Overview 10 21 29 40

Retention Test

Advance Organizer 9 12 19 60

Conventional Overview 9 12 26 53 121

Table 13. Test Characteristics

TEST SITUATION N X SD Range KR-20

Initial Test

A 0 Group 99 29.48 9.48 7-53 .87

C 0 Group 94 28.68 8.78 11-52 .85

Retention Test

A 0 Group 96 26.40 10.88 7-53 .90

C 0 Group 92 25.85 10.60 10.56 .90 Table 14. Means and Standard Deviations of Test Scores by Treatment and Group

Group in Initial Test Retention Test M SD M SD

Advance Organizer 90 29.91 9.27 26.66 11.13

Class 1 16 34.75 11.81 29.06 14.58 Class 2 17 29.94 8.98 27.82 11.17 Class 3 16 30.13 8.13 28.37 8.82 Class 4 20 29.75 9.78 30.30 10.65 Class 5 21 26.19 6.27 19.09 6.67

Conventional Overview 88 28.93 8.92 26.07 10.71

Class 6 19 25.53 10.63 22.05 11.10 Class 7 19 31.53 9.54 30.00 10.94 Class 8 14 26.29 7.64 17.79 7.87 Class 9 20 28.80 7.56 27.20 7.45 Class 10 16 32.38 7.17 32.00 10.32

Total 178 29.43 9.09 26.37 10.90

Note: Maximum score for each test was 58. All values were rounded to the nearest hundredth. Number for each class is the number of students who completed both tests. 123

Each treatment level contained one low-scoring group, i.e.,

Class 5 in the advance organizer treatment, and Class 8 in the con­ ventional overview treatment. Both of these classes were scheduled during the last class period of the day in their respective schools.

A look at the frequency distributions for the two treatment levels (see Appendix D) reveals that the distribution for each treat­ ment is platykurtic (very flat). Figures 8 through 11 show frequency polygons for each set of test scores. These include: Figure 8, advance organizer in itial te st; Figure 9, conventional overview initial test; Figure 10, advance organizer retention test; and Figure

11, conventional overview retention test.

Analysis of Variance

Analyses of variance were calculated using a hand calculator and following procedures outlined by Kennedy (1977, pp. 542-549) for a

One Between-Groups and One Within-Subjects Design.

The number of measures within each group was equalized at 18 per class group. A compromise involving randomly discarding extra scores from classes with more than 18 students and filling in missing scores by adding the mean score for the group until n was 18 was used to equalize numbers per group. A table of random numbers was used in the process of discarding scores. The number of scores added or discarded is shown in Table 16. This compromise equalized n's within groups with a minimum of tampering with actual scores. Equalization of n's had the effect of reducing the resulting F-values and this provided a FREQUENCY 8 iue . rqec Plgn f nta Ts Soe fr dac Ognzr ru (N=99) Group Advance Organizer for Scores Test Initial of Polygon Frequency 8. Figure -■ 9 6 -■ 7 2 -- 4 - - 5 -- - 3 1 .. -- -- TEST SCORES 58) (possible 4* ro 20 25 30 35 40 TEST SCORES (possible 58)

Figure 9. Frequency Polygon of Initial Test Scores for Conventional Overview Group (N=94)

OlPO FREQUENCY iue 0 Feuny oyo o Rtnin et crs o Avne raie Gop (N=87) Group Advance Organizer for Scores Test Retention of Polygon Frequency 10. Figure 15 5 10 20 TEST SCORES 58) (possible 25 30 35 40 45 055 50 60 CTIro FREQUENCY iue 1 Feuny oyo fr eeto Ts Soe o Cnetoa Overview (N=92) Group Conventional of Scores Test Retention for Polygon Frequency 11. Figure - - 9 TEST SCORES 58) (possible ro 128 more conservative estimate of the resulting F value. The means and standard deviations for groups and measures using the adjusted n are shown in Table 17.

The results of the analyses of variance are reported in Table 18.

The table can be interpreted as follows:

The F-ratio of .282 is a measure of the variance between tre a t­ ment groups (A). This value indicates that there was very l i t t l e difference between the two treatment groups. The results for the two groups are extremely close.

The F-ratio of 3.519 is nearly significant (£<.U01) for 8 and 120 degrees of freedom (3.55), and is significant (£<.001) for 8 and infinity (3.27). This indicates that there was a considerable amount of variance among classes nested within each treatment (B/A).

The F-ratio of 9.448 is significant (£<.025) for 1 and 8 degrees of freedom (7.57). This represents an analysis of variance among overall means of the criterion measure £. There was a significant difference between the two measures, the initial test and the retention test.

The F-ratio of .008 is not significant, and indicates that there was very little treatment-measure (AC) interaction.

Finally, the F-ratio of 4.665 is significant (£<.001) with 8 and 120 degrees of freedom (3.55). This indicates that there was significant interaction between classes and tests within each treat­ ment level (BC/A). 129

Table 15. Adjusting Numbers to 18 Per Group

ADVANCE ORGANIZER CONVENTIONAL OVERVIEW GROUPS GROUPS

Class N Change Class N Change rH 00 H 1 16 +2 18 6 19 1

2 17 +1 18 7 19 -1 18

3 16 +2 18 8 14 +4 18

4 20 -2 18 9 20 -2 18 + r\* b 21 -3 18 10 16 00

TOTAL 90 10 90 88 10 90 Table 16. Means and Standard Deviations of Test Scores by Treatment and Group After Equalizing Numbers Within Each Class

Initial Test Retention Test Group na M SD M SD

Advance Organizer 90 30.27 8.99 27.10 10.63

Class 1 18 34.81 11.11 29.06 13.70 Class 2 18 29.94 8.71 27.82 10.84 Class 3 18 30.13 7.64 28.38 8.29 Class 4 18 29.89 9.24 30.50 9.71 Class 5 18 26.56 6.67 19.72 6.98

Conventional Overview 90 29.02 8.68 25.76 10.58

Class 6 18 25.56 10.93 22.28 11.38 Class 7 18 31.89 9.68 29.61 11.13 Class 8 18 26.22 6.63 17.83 6.88 Class 9 18 29.11 7.15 27.06 7.20 Class 10 18 32.33 6.74 32.00 9.70

Total 180 29.66 8.83 26.42 10.65

Note: Maximum te st score was 58. All values were rounded to the nearest hundredth. Number of subjects within each class was equalized by adding the group mean score for each missing score, and by randomly discarding scores from each group for which there were more than 18n per class. Table 17. Analysis of Variance of Test Scores For For One Between-Groups and One Within-Subjects Design

SOURCE df SS MS F

Between Ss 179 29,640.5

Between Groups 9 4,338.139

A 1 147.850 147.850 .282

B/A 8 4,190.289 523.786 3.519**

Within Groups 170

S/B/A 170 25,302.361 148.837

Within Ss 180 5,364.875

C 1 943.761 943.761 9.488*

AC 1 .845 .845 .008

BC/A 8 795.755 99.469 4.665*

SC/B/A 170 3,624.514 21.321

TOTAL 359 35,005.375

*£<.025 (1,8) = 7.57 **£<.001 (8,») = 3.27 132

Hypothesis Testing

The two null hypotheses for this study were:

HOj: There is no significant difference in initial learning between the advance organizer and the conventional overview groups as measured by an objective achievement test.

HOg.- There is no significant difference in retention between the advance organizer and the conventional overview groups as measured by the achievement test readministered three weeks after the initial test.

The .05 probability level was selected as the basis for reject­ ing or failing to reject the null hypotheses.

The dependent variable for both hypotheses was measured using the researcher-developed material processing achievement test. The independent variable was the method of instruction: the interaction of an advance organizer with the reading of a learning passage, vs. the interaction of a conventional overview with the reading of the same learning passage.

On the basis of the information presented in the previous section, the null hypotheses HQ^ and Hq2 are not rejected. Therefore, on the basis of this study, there was no significant difference in achievement between the advance-organizer and the conventional-overview groups on either the initial learning test or the retention test.

Discussion

The findings for this study were not in the direction as expressed in the research hypotheses or in line with evidence as gleaned from the 133

Review of Literature. Therefore, it seems appropriate to examine some possible explanations for what might have happened in the experiment.

This discussion will be organized into four sections. They are: model assumptions for ANOVA, treatments, conditions and arrangements, and criterion measures.

Model Assumptions for ANOVA

Three model assumptions associated with the error components of

ANOVA are commonly associated with use of the ANOVA statistical model.

The f ir s t assumption is population normality, the assumption that error effects are distributed normally in treatment populations. The second assumption is independence, the assumption that error effects are independently determined and distributed both within groups and between treatment populations. The third assumption is homogeneity of variance, or equal variance of error effects across treatment populations. The researcher must be aware that violation of one or more of these assumptions can result in a biased F-test.

With regard to the population normality assumption, Glass and

Stanley (1970) state "with respect to the probability of a type I error, we can safely conclude that the ANOVA assumption of normality is of almost no importance. It can be violated and the probability of a type I error remains almost exactly at the value specified by the experimenter, namely a " (p. 372).

With regard to the assumption of independence, Kennedy (1977) states "It is frequently possible (necessary) to randomly assign intact classrooms to respective levels of treatment. When this is done, the independence-of-response assumption is seriously threatened if 134 individual subjects remain the units of analyses" (p. 45). Kennedy continues "observations made on all subjects who have been exposed to the particular treatment will not be independent since a meaningful correlation exists between class membership and performance" (p. 46).

"When multiple classrooms are exposed to a treatment, the classroom— not the student—should constitute the unit of analysis. That is, the mean performance of the classrooms—not the scores of the students—should be subjected to analysis because classroom means within levels of treatment are more free to vary independently" (p. 46).

Glass and Stanley continue with regard to heterogeneous variances

"the fixed effects ANOVA appears to be remarkable insensitive to departures from normality; and when n's are equal {emphasisadded}

it is equally unaffected by heterogeneous variances. Box has used the word 'robustness' for this insensitivity of a statistical violation of its assumptions" (p. 374).

Glass and Stanley cite several research studies on the effect of heterogeneous variances. They note that all of these studies corroborate in part or entirely the following conclusions:

1. When the sample sizes are equal, the effect of heterogeneous variances on the level of significance of the F-test is negligible.

2. When the sample sizes and variances are unequal and fewer persons are sampled from the populations with larger variances, the probability of a type I error is greater than normal a {the nominal probability}. In other words, the effect of heterogeneous variances in this case is to shift the distribution of F-ratios to the right. 135

3. When the sample sizes and variances are unequal and greater numbers of persons are sampled from the populations with larger variances, the probability of a type I error is less than a. The effect of heterogeneous variances in this case is to shift the distribution of F-ratios to the left. (p. 372)

Kennedy (1977) comments on the robustness of ANOVA with regard

to violation of normality and homogeneity of variance assumptions when group n's are equal or nearly equal, and continues "Problems

do arise, however, when marked heterogeneity of variance exists and

group n's are noticeably dissimilar. These problems are further

complicated by the fact that there is no direct way that the extent

of heterogeneity of variance can be assessed {emphasis added)"

(p. 156).

With regard to the present study, the following conclusions are

drawn relative to violation of the ANOVA assumptions and interpret­

ation of the F-ratios (See Table 17):

1. The F-ratio of .282 shown as a measure of the variance

between treatment groups Aj and (advance organizer and conventional

overview respectively) is so small that there is no question about

there being very l i t t l e difference in performance between the two

groups.

2. The F-ratio of 3.519 for variance of groups within each

treatment level (B/A) is nearly significant at £<.001 for 8 and 120

degrees of freedom (3.55), and is significant at £<.001 for 8 and

infinity degrees of freedom (3.27). To be significant at £<.05 at 8

and 120 degrees of freedom, the ratio would have to be only 2.02. A 136

casual look at the mean scores reveals a tremendous difference among

groups. Surely any bias present because of heterogeneity of variance would not be sufficient to change this conclusion.

3. The F-ratio of 9.488 for variance between the initial learn­

ing and retention test measurements is an expected result and is significant at £<.025 with 1 and 8 degrees of freedom (7.57). The ratio required for significance £<.05 is 5.32. Again, there is considerable leeway before the significance of this ratio would be rejected £<.05. The researcher feels quite safe in assuming that any bias would not change the conclusion here.

4. The F-ratio of .008 for interaction between treatment level and test (AC) is definitely not significant. Therefore, there is little danger of a Type I error.

5. The F-ratio of 4.665 for interaction between classes and tests within each treatment level (BC/A) is significant £<.001 with 8 and

170 degrees of freedom (3.55 for 8 and 120). At £<.05, the ratio would only have to be 2.09 at 8 and 120 degrees of freedom, and at 8 and infinity degrees of freedom, the ratio would have to be only 1.94.

Again, i t seems highly unlikely that the influences of bias because of failing to meet normal ANOVA assumptions would change the conclusion of significance in this case.

Treatments

Kozlow's meta-analysis found that as the number of concepts presented in an advance organizer increased, the facilitative effect of the organizer decreased. As the rate of introduction of new material increased, advance organizers tended to show less facilitative 137 effect. Kozlow also found that the type of instructional strategy influenced the facilitative effect of the organizer. In particular, the CEC (characterization, exemplification, characterization) strategies when used in advance organizers were significantly more effective than the use of generalization or other strategies alone.

The advance organizer used in this study had a very high concept density. The entire material processing universe as identified by the

Industrial Arts Curriculum Project (forming, separating, combining) was presented in two short ten-minute video tapes. In order to present this many different ideas in the time allowed, the number of examples was restricted to about two per concept. All examples used related attributes of the concept. No examples of unrelated attributes were used, and the viewers did not have the opportunity to practice classifying concepts while viewing the video tapes. As such, the advance organizer may not have been as effective as a less complex organizer which, for example, only treated one segment of the material-processing hierarchy (e.g., forming) during the time available.

A second potential difficulty with the treatments lay in the problem of differentiating between what was an advance organizer and what was a conventional overview. In an effort to equate the amount of instruction for both treatment groups, examples of material processing practices from each major category of material processing in the advance organizer were included in the conventional-overview tapes— although in random order and unrelated to the organizing concepts identified in the advance organizer. It is conceivable, however, that the conventional overview also functioned as an advance organizer. 138

A third potential problem existed because the design did not provide for a measure of subsuming concepts possessed by subjects for either treatment level either before or after viewing the video tapes.

As such, one cannot speculate directly on the effect of either type of presentation on the subsuming concepts developed by the viewers.

A fourth potential problem is related to the fact that no "expert" or empirical test was used in a systematic way to validate the advance organizer. It seems likely that even if an "expert" had been used, the judgement may not have been as reliable as an empirical test. The subjects' subsuming concepts are products of their experience and psy­ chological structure, not necessarily the products of the logic of educational theorists. A problem of major importance to future resear­ chers is to identify ways to measure subjects' subsuming concepts.

Additional research is also needed on the effectiveness of block diag­ rams in helping subjects learn hierarchical concepts.

A fifth potential problem lay in the proximity of the advance organizer to the learning materials. Although Dawson (1966) found his advance organizer to be more effective when administered twenty-four hours in advance of the learning task, there is no evidence one way or the other in this study to describe the effectiveness or lack of effectiveness from administering the advance organizers twenty-four hours in advance of reading the learning passages. This presents another potential explanation for the lack of organizer effectiveness when compared with expectations.

A sixth potential problem could have occurred because of the amount of discussion used during instruction. In order to maintain 139

control, and to help rule out teacher effect, no discussion or very

l i t t l e discussion of the video tapes was permitted. This control

feature eliminated a normal aspect of teacher-student interaction,

and as such could have restricted the effectiveness of the advance organizer.

Finally, it is possible that the logical hierarchy used for the

advance organizer in this study may not be the most psychologically meaningful hierarchy for junior-high-level students in learning the type of material presented in this experiment. More evidence is needed concerning available subsuming concepts of the junior-high student, and efforts need to be directed toward developing techniques for identifying available subsuming concepts for this type of subject matter.

Conditions and Arrangements

Intelligence test scores and related information such as reading level were not available to the researcher. Such information would have been useful in assessing the composition of each class. It appears from the test scores obtained by this experiment that subjects may not have been from a typical population.

Had ability-level data been available, as well as the opportunity to randomly assign subjects to treatment and/or control groups, considerably more information could have been obtained from the study

relative to the amount of learning which took place and the inter­ action effects of the treatment with various student characteristics.

Student performance on the two tests was quite varied. A number of students scored higher on the retention test than they scored on 140

the initial learning test. Many other students performed at an

above-chance to above-average level on the initial learning test and

then performed only at chance level on the retention test. L ittle

evidence was available to the researcher which could be used to

analyze and explain these phenomena. The student who scored well on

the initial learning test and then scored no more than chance on the

retention test may have forgotten what was learned, may have only

learned the material in a rote manner for the f ir s t te st, or simply

may not have been motivated to do well on the second test.

Absences and tardinesses during the experiment could have had

an effect on the outcome. The mean scores for both initial learning

and retention measures of three of the classes were considerably lower

than the mean scores for the rest of the classes. By chance, two of

these classes (class 6 and class 8) were assigned to the conventional- overview treatment, and the third class (class 5) was assigned to the

advance-organizer treatment. When loss of subjects during the exper­

imental period is considered (see Table 18), classes 6 and 8 had a

high percentage of absences and tardies. This loss may have had either a positive or a negative effect on the overall class mean

score. In contrast to classes 6 and 8 which had a high percentage of loss (17.4 and 22 percent respectively) classes 2 and 3 in the

advance-organizer group also had a high percentage of loss (15.0 and

15.8 percent respectively) but s till had class means which approximated

the overall mean for the treatment group. The absences in question may have been related to an affective component of the experiment, or may simply have been caused by factors unrelated to the experiment. 141

Table 18. Loss of Subjects From the Experiment

Class Number Useable Loss from Percentage No. Students Scores Original Sample Loss

A 0 Group

1 17 16 1 5.9

2 20 17 3 15.0

3 19 16 3 15.8

4 22 20 2 9.1

5 23 21 2 8.7

Subtota1 101 90 11 10.9

C 0 Group

6 23 19 4 17.4

7 21 19 2 9.5

8 18 14 4 22.2

9 20 20 0 0.0

10 16 16 0 0.0

Subtotal 98 88 10 14.3

TOTAL 199 178 21 12.6

MEAN 19.9 17.8 2.5 12.6 142

Criterion Measures

Although valid and reliable, the criterion measures used in this research clearly concentrated on the measurement of lower-level cognitive knowledge. The criterion task was one of recognition rather than of recall, application, or problem solving. Although the type of criterion measure used in this study is consistent with criterion measures used in a good many other advance organizer studies--some showing significant facilitative effects for the advance organizer treatment--it is possible that students could have relied a good deal on rote rather than meaningful learning. The problem of constructing a criterion measure and not using questions which are answered directly by the advance organizer is a d ifficu lt one. But, based on Ausubel's theory, it would appear that a criterion test which measures higher- order cognitive knowledge would have more potential for measuring meaningful learning and retention.

Summary

Chapter IV has presented an overview of test characteristics and test data. An analysis of the data was made by analysis of var­ iance. Based on this analysis neither null hypothesis could be rejected. A discussion of results suggested several possible reasons for the outcome of the experiment.

Chapter V will summarize major topics of the dissertation.

Conclusions will be drawn from the findings, and recommendations for future research and for educational practice will be made. CHAPTER V

SUMMARY, CUNCLUSIONS AND RECOMMENDATIONS

This chapter presents a summary of the study and the findings.

Conclusions and recommendations are also presented.

Summary of the Research

Review of Literature

Ausubel's Assimilation Theory of meaningful learning and retention is a relatively new theory which is based in cognitive psychology.

The theory focuses on meaningful verbal learning. According to the theory, meaningful learning occurs when new ideas are linked or assimilated into the individual's cognitive structure. In order to make this process more efficien t, Ausubel (1978) advocated the use of advance organizers which were defined as "introductory material which is structured at a higher level of generality, abstractness, and inclusiveness than the material i t introduces" (p. 171). As presented in more detail in Chapter II, Ausubel describes different kinds of meaningful learning and uses two important principles to explain how advance organizers work: progressive differentiation and integrative reconciliation.

143 144 Chapter II presented an overview of selected literature reviews

which pertain to Ausubel's theory. In a review of an article by

Lawton and Wanska (1977, pp. 242-243), a number of guidelines for

developing and evaluating advance organizers were listed. Two meta­

analysis studies which analyzed advance-organizer research between

1963 and 1977 were also reviewed. A number of studies were identif­

ied which used advance organizers developed in other than prose

form.

The Wisconsin Model of learning and Piaget's model of cognitive

development were reviewed as two other contemporary viewpoints of

cognitive processing. Finally, pertinent aspects of the Industrial

Arts Curriculum Project were reviewed. This part of the review was

most directly concerned with the evolution of a hierarchy of material

processing concepts which served as a basis for developing the advance

organizers used in this study.

The Problem

When one considers the amount of research which has been done with behavioral and cognitive field theories other than Ausubel's,

the total amount of research with Ausubel's theory has been exceedingly

small. The amount of research with advance organizers in industrial

arts has included only three studies prior to this one. No research

has been conducted which uses the Industrial Arts Curriculum Project

taxonomies as a basis for generating an advance organizer.

This study was designed to add to the evidence available about

Ausubel's Assimilation Theory, and about the effectiveness of advance

organizers in teaching industrial-arts subject matter. In order to do this, this study compared the initial learning and retention of two groups of industrial-arts students after each group had received a specified sequence of instruction.

The Experimental Design

Because i t was necessary to use intact classes, a One Between-

Groups and One Within-Subjects partial hierarchical design was used for this study. There were two treatment levels, one for the advance organizer treatment and the other for the conventional overview treatment. Five classes of students were nested within each of the treatment levels. Approximately 18 students were, in turn, nested within each class group. There were two dependent variables, initial learning and retention. This repeated-measures aspect constituted the within-subjects part of the design. Data for both dependent variables were obtained using the researcher-developed multiple- choice test.

The Sample

Subjects for the experiment were enrolled in two of six junior high schools in Cedar Rapids, Iowa. Approximately one-half of the subjects were eighth graders and the remaining students were ninth graders. Both grade levels were enrolled in each class. Each student was enrolled in one of the following industrial arts subject areas: graphic arts, woods and plastics, or manufacturing. Ten intact classes were used for the experiment. Each class was randomly assigned to one of the treatment levels in such a way that each teacher and each type of subject matter were proportionately represented in each treatment level. 146

Procedures

The treatments were administered over a period of four days.

Testing occurred on the fifth day and again three weeks later. On the f ir s t day each treatment group viewed either the f ir s t advance- organizer video tape or the f ir s t conventional-overview video tape.

Viewing the tape took about ten minutes of viewing time. On the second day, both treatment groups read the f ir s t reading which was identical in content and organization for each group. The reading took about twenty minutes. On the third day, each treatment group viewed an appropriate second video tape, either an advance organizer or a conventional overview. Viewing the second video tape took about ten minutes of viewing time. On the fourth day, each treatment group read a second reading passage which was different from the f ir s t read­ ing but was identical in content and organization for each group.

During the remaining part of each class day, students performed their regular class assignments (not directly related to the experiment).

On the fifth day, all classes took the initial learning test. Three weeks later, all classes took the retention test.

Analysis of Data

The criterion test used to measure initial learning and retention was administered to pilot groups and revised four times before it was used in the experiment. A jury was used to validate the test items against the reading material. The obtained reliability estimates, item difficulty, and item discrimination indices were well within acceptable ranges for the experiment. 147

An analysis of variance was used to analyze the data. Class sizes were adjusted to equal-n size by randomly discarding scores from classes with more than 18 students and by adding the respective group mean score n times to fill in missing scores in classes with less than 18 useable scores. The analyses were performed using a hand calculator and following procedures outlined by Kennedy (1977, pp. 542-

549) for a One Between-Groups and One Within-Subjects Design.

Findings

On the basis of the statistical analysis, neither null hypoth­ esis could be rejected (£<.05). As such, the two findings for the study were:

1. There was no significant difference in initial learning between the advance-organizer group and the conventional-overview group as measured by the criterion test.

2. There was no significant difference in retention between the advance organizer group and the conventional overview group as meas­ ured by the criterion test when administered three weeks after the initial learning test.

Conclusions

Based upon the experimental findings, two conclusions were reached. They were:

1. The advance organizer and the conventional overview tre a t­ ments were equally effective as measured by the initial learning test used in this experiment. 148

2. The advance organizer and the conventional overview tre a t­ ments were equally effective as measured by the retention test used in this experiment.

Recommendations

Recommendations for Future Research

The Review of Literature reveals that a large number of research studies show a facilitative effect favoring the use of advance organ­ izers. This study was the first to use an extensively researched and developed hierarchy of concepts in industrial technology as a basis for developing an advance organizer. It is only the fourth study of advance organizer effectiveness using industrial arts content. This study was limited in duration and was restricted to an experimental design which accommodated intact classes. As such, many questions relative to the effectiveness of advance organizers for teaching industrial arts content remain unanswered. Accordingly, the following recommendations are made:

1. Similar studies are needed which employ a true experimental design (Campbell & Stanley) and which enable analyses of the interact­ ion between treatments and student characteristics such as intellect­ ual ability. Greater attention should be given to the learner's prior knowledge and/or existing subsumers than was possible in this study.

2. Future studies should be designed so that measures of learning directly attributable to the advance organizer and the conventional overview can be measured. 149

3. Alternate kinds of criterion tests should be developed which measure the learning and retention of higher levels of cognitive knowledge than were measured in this study.

4. Additional research is needed concerning the effectiveness of using block diagrams to teach hierarchical concepts.

5. Advance organizer research using other parts of the Industrial

Arts Curriculum Project taxonomies (personnel, management, other aspects of material processing) should be carried out.

6. Alternate forms of the advance organizer usedin this study should be developed and tested. Additional research comparing the relative effectiveness of aural, written, and interactive organizers for teaching industrial arts content to junior-high-school students is needed. Advance organizers with a lower concept (progression) density should be tested. Particular attention should be focused on the kinet­ ic structure of the organizer as well as on the teaching sequence of characterization and exemplification acts. The predevelopment activities, prematerial instructions, and within-material presentation activities outlined by Klausmeier and Hooper (1974) should receive attention during advance organizer development as well as in the instructional sequence of the learning task in future studies.

7. Longer termed studies and studies which integrate advance organizers into the ongoing class activities to a greater degree than was possible in this study should be carried out.

8. Studies should be conducted which measure the affective resp­ onses of students when advance organizers are used in the industrial arts classroom. 150

Recommendations Related to Education

Given the facts that advance organizers have been facilitative in many studies, and that they were significantly facilitative in

Dawson's study (utilizing industrial arts content), the following recommendations are made for educational practitioners in the indust­ rial arts field.

1. Teachers and prospective teachers should be made aware of the tenets of Ausubel's Assimilation Theory.

2. Industrial arts teachers should continue to test the effectiveness of advance organizers as an instructional tool for teaching industrial arts subject matter. APPENDIX A

ADVANCE ORGANIZER I

151 ADVANCE ORGANIZER I

The content of Advance Organizer I is desdribed in this Appendix.

This description is made up of three parts:

The first part of the description is a list of visuals which

were used in the video tape. These visuals were basically of two

types: a series of black and white block diagrams which showed

key material processing terms in an hierarchical arrangement, and a

series of material processing demonstrations which were used as

exemplars of the concepts shown on the block diagrams. The material

processing demonstrations were video taped in color. Each visual

segment is numbered on the lis t which follows:

The second part of the description is a script which was put on

the sound portion of the video tape. The numbers from the list of

visuals are included within the script to show how the visuals

related to the script.

The third part of the description is the series of block diagrams which were used as part of the visuals. These diagrams are listed by figure number in the List of Visuals and in the Table of Contents.

This video tape was ten minutes in length. Copies of the tape

can be obtained by contacting the author.

152 LIST OF VISUALS

FOR ADVANCE ORGANIZER I

1. MATERIAL PROCESSING (Signboard)

2. Forging hot steel with atrip hammer

3. Spinning metal on a spinning lathe

4. LEVELS OF MATERIAL PROCESSING (Figure 12)

5. PRIMARY PROCESSING (Figure 13)

6. Various sizes of lumber

7. SECONDARY PROCESSING (Figure 14)

8. Parts of a wooden house frame

9. SECONDARY MATERIAL PROCESSING (Figure 15)

10. FORMING (Figure 16)

11. STRUCTURE (Figure 17)

12. STRUCTURE (Figure 18)

13. EXTERNAL STRUCTURE (Figure 19)

14. EXTERNAL STRUCTURE (Figure 20)

15. Shaping a piece of clay in the hands--rolling a ball

16. Shaping a piece of clay on a table-rolling a cylinder

17. Pressing clay into a plaster mold

18. Examples of clay forms and shapes

153 154

ADVANCE ORGANIZER I LIST OF VISUALS, continued

19. INTERNAL STRUCTURE (Figure 21)

20. INTERNAL STRUCTURE (Figure 22)

21. A hardness tester

22. Wood being tested in the tester

23. Second piece of wood being tested in the tester

24. FORMING (Figure 23)

25. SECONDARY MATERIAL PROCESSING (Figure 15)

26. SEPARATING PROCESSES (Figure 24)

27. Bandsawing the shfcpe of a paddle

28. Belt sanding the edges of the paddle

29. Routing the edges of the paddle

30. SEPARATING (Figure 25)

31. SECONDARY MATERIAL PROCESSING (Figure 15)

32. COMBINING PROCESSES (Figure 26)

33. Nailing a dado joint together

34. Assembling a butt jo in t with screws

35. The parts of a dovetail joint

36. Spot welding

37. COMBINING (Figure 27)

38. MATERIAL PROCESSING (Figure 28)

39. MATERIAL PROCESSING (Figure 29)

40. FORMING PROCESSES (Figure 30)

41. CASTING AND MOLDING (Figure 31

42. MOLD (Figure 32) 155

ADVANCE ORGANIZER I LIST OF VISUALS, continued

43. Pouring water in an ice cube tray

44. Frozen ice cubes

45. A foundry matchplate showing patterns

46. Ramming a sand mold

47. The cavity in the sand mold

48. A cope and drag showing both parts ofthe sand mold

49. Pouring molten aluminum into the sand mold

50. Opening the sand mold

51. Removing cast aluminum parts from the sand mold

52. Stirring clay slip

53. Pouring clay slip into a plaster mold

54. Showing the drying effect on the slip near the edge of the mold

55. Pouring excess slip out of the mold

56. Showing the shell of clay in theplaster mold

57. Opening the plaster mold

58. FORMING PROCESSES (Figure 30)

59. COMPRESSING AND STRETCHING (Figure 33)

60. PLASTIC NATURE (Figure 34)

61. Pinching clay

62. A flat strip of clay

63. Sheetmetal box cutout

64. Bending sheetmetal on the box and pan brake

65. Bending the sides of the box on the box and pan brake

66. Detail of the corner of the sheetmetal box 156

ADVANCE ORGANIZER I LIST OF VISUALS, continued

67. Spinning aluminum on the spinning lathe

68. Completed spun products

69. Hot metal in forge furnace

70. Hammering hot metal on an anvil

71. FORMING PROCESSES (Figure 30)

72. CONDITIONING PROCESSES (Figure 35)

73. Hot metal in forge furnace

74. Quenching hot steel in quenching oil

75. Filing soft steel

76. Filing hardened steel

77. Striking dried clay with a hammer

78. Striking fired clay with a hammer

79. Spinning aluminum on a spinning lathe

80. MATERIAL PROCESSING (Figure 23)

81. FORMING PROCESSES (Figure 24)

82. SEPARATING (Figure 36)

83. COMBINING (Figure 37)

84. MATERIAL PROCESSING (Figure 29)

85. MATERIAL PROCESSING (Signboard) SCRIPT FOR

ADVANCE ORGANIZER I

MATERIAL PROCESSING

(1) Industrial products and processes are a central part of our lives. This video tape (2) was designed to help you learn some general principles of (3) how materials are processed into useful products.

(4) There are basically two levels of material processing: pri­ mary processing and secondary processing.

(5) Primary processing changes materials from their natural state into standard stock.

(6) For example, wood is found as a living tree in its natural state. Primary processing changes the tree into standard-sized boards called standard stock.

(7) Secondary processing changes standard stock into a completed product.

(8) These boards could be changed into parts of houses or many other finished products by secondary processing. This video tape focuses on secondary processing - the changing of standard stock into finished products.

157 158

(9) All standard stock is processed in three basic ways: by forming, by separating and by combining. Remember this diagram. We will refer back to these processes throughout the video tape.

(10) Forming changes the structure of a material without adding or subtracting material.

(11) The key element of this definition is the word structure.

(12) Two types of structure are involved: external structure and internal structure.

(13) External structure means the outward appearance of the material. It refers to what can be seen.

(14)Usually, external structure is used to refer to the size, shape, or surface finish of a material.

(15) Shaping a piece of clay is a good example of how external structure is changed by a forming process. Clay can be rolled into a ball . . ., (16) formed into a cylinder . . ., (17) pressed into a mold or formed into some other shape.

(18) In all of these examples, there has been no addition or subtraction of material. Only the size, shape, and surface finish of the clay have been changed.

(19) Internal structure means the internal qualities of the material. Sometimes the internal structure cannot be seen directly.

(20) The internal structure of the material affects such physical properties as hardness and strength. These properties can be demon­ strated easily. 159

(21) This hardness tester can be used to demonstrate the internal qualities of materials. We will te st two samples of wood. A round ball will be forced into the surface of each piece of wood. (22) If the wood is soft, the ball will penetrate rapidly. If the wood is hard, the ball will not penetrate as fast or as deep.

(23) What conclusions can you draw about the internal qualities of these two pieces of wood?

(24) Forming processes will be described in greater detail later in the video tape.

(25) Remember this diagram? Separating is the second major type of processing.

(26) A separating process is any process which removes or sub­ tracts material from a workpiece to make a useful product. Separating material is another way to produce a product of the right size, shape, or surface finish.

(27) This band saw is being used to separate material from a piece of wood. The product is a paddle for a Jokari game. Sawing produces the right size and shape for the paddle. Additional processes will be used to produce the completed shape.

(28) Belt sanding is another separating process. It is being used to smooth the edges of the paddle.

(29) Routing, another separating process, is being used to round the edges of the paddle.

(30) Separating processes will be described further in a second video tape. 160

(31) Recall this diagram? The last major category of material processing is combining.

(32) Combining processes assemble or add material to make a useful product. Most completed products are a combination of parts which are assembled into one unit. It is not possible or practical to make some products from a single piece of standard stock.

(33) In some cases, special joints are used to fasten parts together. This dado joint is being assembled with glue and nails.

(34) This common butt joint is held together with screws.

(35) The parts of this dovetail joint have a special shape. They fit together tightly.

(36) Spot welding is often used to assemble metal materials.

(37) Combining processes will be described more fully in the next video tape.

(38) So far, we have classified material processing into three general groups. Forming processes change the external and internal structure of the material. Separating processes produce new shapes and sizes by removing excess material. Combining processes assemble parts to make the finished article.

(39) Each of these groups of processes is made up of subgroups.

Each subgroup has a number of common characteristics.

(40) All forming processes can be classified into three sub­ groups: casting and molding, compressing and stretching, and condit­ ioning. In a sense, these three subgroups are a new definition of forming. 161

(41) Casting and molding involve two principles: the use of a mold, and changing the state of the material one or more times. These two principles work together to change the structure of the material.

(42) A mold has a cavity which has the same size, shape, and surface finish as the part which is being formed.

(43) Ice cubes are made by casting. Water is already in a liquid state. It is poured into an ice cube tray which is a kind of permanent mold made of plastic or metal.

(44) The mold is put into the freezer where the water is frozen into a solid state. The water now has a new structure called ice.

(45) Aluminum is often cast into a sand mold. (46) The mold is prepared by forming sand against a pattern.

(47) The cavity in the completed mold is the same shape as the pattern. (48)

(49) Melted aluminum is poured into the sand mold.

(50) When the aluminum cools and becomes solid again, the mold can be opened, and (51) the cast parts can be removed.

(52) Clay is made liquid by mixing it with water. This water-clay mixture is called slip.

(53) When the clay slip is poured into a plaster mold, the water moves out of the clay into the plaster.

(54) After a short time, the excess liquid slip can be poured (55) out of the center.

(56) A solid shell of clay is left near the surface of the mold.

(57) The mold is opened, and the solid clay casting can be removed. 162

(58) The second subgroup of forming processes is compressing and stretching.

(59) Forming materials by compressing and stretching involves three principles: the material must be a solid with a plastic nature; force must be used to change the structure of the material; and, a shaping device must be used.

(60) The term plastic nature, as used in this sense, refers to the internal quality of the material, rather than to a specific kind of materi al.

A material has a plastic nature if i t can be reshaped without breaking.

(61) This piece of moist clay has a plastic nature. If it is pinched between the fingers, its shape will change without breaking.

When the force is removed, the clay retains its shape.

(62) If a strip of moist clay is bent like this, the inside of the bend will be compressed, or squeezed together.

The outside of the bend will be pulled, or stretched apart.

The shape of the clay has been changed by compressing and stretching.

(63) This piece of sheet metal can be formed into a box by com­ pressing and stretching.

(64) F irst, the ends are bent . . ., (65) then the sides are bent.

(66) Notice the tabs which will be used to fasten the corners together.

(67) This metal spinning operation forms metal by compressing and stretching. The workpiece starts out as a fla t metal disc. As the 163

tool moves back and forth against the spinning disc, it stretches and compresses the metal over a metal form.

(68) The completed part has the same shape as the form which was

used.

(69) Thicker parts are often compressed and stretched by forging.

First, the metal is made plastic by heating.

(70) Then the material is hammered or pressed into shape.

(71) The third subgroup of forming processes is conditioning.

(72) Conditioning processes comnonly use heat, chemical or mechanical forming processes to change the internal structure of materi als .

(73) Heat is often used to change the internal structure of metals. Metals are made up of crystals or grains. As metals are heated, the size of the crystals changes. When steel is heated to the right temperature, the crystals get smaller and the grain becomes very fine.

(74) By cooling the steel very rapidly, the fine grain structure does not have a chance to change. The fine grain structure makes the steel very hard.

(75) We can demonstrate the effect of hardening on the screw­ driver blade which was forged a few moments ago. If we file the end that was not heated and cooled rapidly, we find that i t is soft. It can be filed easily.

(76) If we attempt to file the hardened end of the blade, the file does not cut the steel because i t is too hard. 164

(77) Clay is fired at a high temperature to improve its strength and hardness. If this piece of dried clay is struck with a hammer, it shatters.

(78) A similar piece of fired clay does not break until struck several times by the hammer.

(79) This spinning process is changing the internal structure of the aluminum disc as well as its external shape. Working the metal - stretching and compressing i t back and forth - changes the grain structure and causes the aluminum to harden. If the aluminum hardens too much, it will lose its plastic nature and tear. It can be restored to its original softness by heat treating.

(80) Remember this diagram? We have described the general principles involved in each major category, forming, separating and combining.

(81) We have also described three subgroups of forming processes: casting and molding, compressing and stretching, and conditioning.

(82) In the next video tape the subgroups of separating will be described.

(83) The subgroups of combining will also be defined. Levels of MATERIAL PROCESSING

- PRIMARY PROCESSING

*— SECONDARY PROCESSING

Figure 12.

PRIMARY PROCESSING

Changes Materials

from NATURAL STATE

to STANDARD STOCK

Figure 13. 166

SECONDARY PROCESSING

— Changes Materials

from STANDARD STOCK

to COMPLETED PRODUCT

Figure 14.

SECONDARY MATERIAL PROCESSING

SEPARATINGFORMING COMBINING

Figure 15. FORMING

Figure 16.

STRUCTURE

Figure 17. 168

STRUCTURE

EXTERNAL INTERNAL STRUCTURE STRUCTURE

Figure 18.

EXTERNAL STRUCTURE

— Relates to

OUTWARD APPEARANCE

Figure 19 EXTERNAL STRUCTURE

— Examples:

— Size — S h ap e —Surface Finish —Other Properties

Figure 20.

INTERNAL STRUCTURE

— Relates to

INTERNAL PROPERTIES

Figure 21. INTERNAL STRUCTURE

L Examples:

— Strength — H ard n ess

—Stiffness

—Other Properties

Figure 22.

FORMING

>- CHANGES STRUCTURE

Figure 23. SEPARATING PROCESSES

Main Characteristic

REMOVE or SUBTRACT material from the work piece.

Figure 24.

SEPARATING

r REMOVES MATERIALS

Figure 25. COMBINING PROCESSES

— Main Characteristic

ASSEMBLE or ADD material to make a useful part

Figure 26.

COMBINING

Figure 27. 173

MATERIAL PROCESSING

SEPARATING COMBININGFORMING

CHANGES REMOVES ASSEMBLES STRUCTURE MATERIAL MATERIAL

Figure 28. MATERIAL PROCESSING

SEPARATING COMBINING

MIXING CASTING & DIRECT MOLDING - SHEARING - CHIP REMOVING COATING COMPRESSING & STRETCHING NON-DIRECT BONDING

- FRACTURING CONDITIONING MECHANICAL - AGENT SEPARATING FASTENING

Figure 29 FORMING PROCESSES

CASTING and MOLDING

- COMPRESSING and STRETCHING

CONDITIONING

Figure 30.

CASTING and MOLDING PROCESSES

Two Characteristics

1. Uses a MOLD

2. CHANGES THE STATE of the material one or more times.

Figure 31. 176

MOLD An internal cavity with the same SIZE, SHAPE, SURFACE FINISH a s the part to be cast

Figure 32.

COMPRESSING and STRETCHING PROCESSES

*— Three Characteristics:

1. The material must be SOLID with a PLASTIC NATURE

2. FORCE is used to change the STRUCTURE

3. A SHAPING DEVICE is used

Figure 33. PLASTIC NATURE RESHAPED WITHOUT BREAKING

Figure 34.

CONDITIONING PROCESSES

COMMONLY USE

-HEAT

-CHEMICAL

-MECHANICAL FORMING PROCESSES

Figure 35. SEPARATING

DIRECT

— SHEARING

CHIP REMOVING

NON-DIRECT

— FRACTURING

AGENT SEPARATING Figure 36.

COMBINING

MIXING

COATING

BONDING

MECHANICAL FASTENING

Figure 37. APPENDIX B

ADVANCE ORGANIZER II

179 ADVANCE ORGANIZER II

The content of Advance Organizer II is described in this Appendix.

This description is made up of three parts:

The first part of the description is a list of visuals which were used in the video tape. These visuals were basically of two types: a series of black and white block diagrams which showed key material processing terms in a hierarchical arrangement, and a series of material processing demonstrations which were used as exemplars of the concepts shown on the block diagrams. The material processing demonstrations were video taped in color. Each visual segment is numbered on the list which follows.

The second part of the description is a script which was put on the sound portion of the video tape. The numbers from the list of visuals are included within the script to show how the visuals related to the script.

The third part of the description is the series of block diagrams which were used as part of the visuals. These diagrams are listed by figure number in the l i s t of visuals and in the Table of Contents.

This video tape was ten minutes in length. Copies of the tape can be obtained by contacting the author.

180 LIST OF VISUALS

FOR ADVANCE ORGANIZER II

Note: Figures 12 through 37 are found in Appendix A.

1. MATERIAL PROCESSING ( Signboard)

2. MATERIAL PROCESSING (Figure 28)

3. FORMING PROCESSES (Figure 30)

4. SEPARATING PROCESSES (Figure 36)

5. COMBINING (Figure 37)

6. SEPARATING PROCESSES (Figure 24)

7. SEPARATING (Figure 38)

8. SEPARATING (Figure 36)

9. DIRECT SEPARATING (Figure 39)

10. DIRECT SEPARATING PROCESSES (Figure 40)

11. Cutting metal on the squaring shear

12. Notching metal on the notcher

13. Cutting sheetmetal with hand snips

14. Routing a dovetail joint

15. Drilling the end of a piece of wood

16. Cutting a dado on the table saw

181 182

ADVANCE ORGANIZER II LIST OF VISUALS, continued

17. Bandsawing the irregular shape of a paddle

18. Belt sanding the edge of the paddle

19. Shaping the edge of the paddle on a shaper

20. SINGLE POINT TOOL (Figure 41)

21. The underside of a hand plane

22. Planing a board with a hand plane

23. Point to the bottom of the hand plane

24. Closeup view of the end of a twist drill

25. Drilling a piece of wood

26. Drilled hole in board with shavings

27. NON-DIRECT SEPARATING (Figure 42)

28. NON-DIRECT SEPARATING (Figure 43)

29. FRACTURING (Figure 44)

30. Closeup of layered limestone

31. Striking stone with a masonry hammer

32. Sheet of glass

33. Scribing a line on the glass

34. Applying force (tapping) the scribed glass

3b. AGENT SEPARATING (Figure 45)

36. View of electro-discharge machining

37. Completed part machined by EDM

38. Flame cutting a piece of steel

39. Closeup of end of flame cut steel

40. MATERIAL PROCESSING (Figure 28) 183

ADVANCE ORGANIZER II LIST OF VISUALS, continued

41. COMBINING PROCESSES (Figure 26)

42. COMBINING PROCESSES (Figure 37)

43. MIXING PROCESSES (Figure 46)

44. Stirring clay slip

45. Mulling foundry sand

46. MIXING PROCESSES (Figure 47)

47. COMBINING PROCESSES (Figure 37)

48. COATING PROCESSES (Figure 48)

49. COATING PROCESSES (Figure 49;

50. Brushing glaze on a slip-cast clay figure

51. Brushing lacquer on a wooden paddle

52. COMBINING (Figure 37)

53. BONDING (Figure 50)

54. FUSION BONDING (Figure 51)

55. Welding with an oxy-acetylene flame

56. Spot welding pieces of sheet metal

57. ADHESIVE BONDING (Figure 52)

58. Applying glue to a dado joint

59. Applying glue to the end of a board

60. Assembling the dado joint

61. COMBINING (Figure 37)

62. MECHANICAL FASTENING (Figure 53)

63. Examples of mechanical fasteners: buttons, shoe laces, staples, nails, bolts ADVANCE ORGANIZER II LIST OF VISUALS, continued

64. Nailing a dado joint together

65. Assembling a butt jo in t with wood screws

66. Closeup of rolled sheet metal joint

67. Forming a seam for a rolled joint

68. Closeup of rolled shape

69. Assembling the two pieces of the sheetmetal joint

70. Parts of a dovetail joint

71. Assembling the dovetail joint

72. Still shot of dovetail parts

73. MATERIAL PROCESSING (Figure 28)

74. FORMING PROCESSES (Figure 30)

75. SEPARATING (Figure 36)

76. DIRECT SEPARATING (Figure 40)

77. NON-DIRECT SEPARATING (Figure 43)

78. COMBINING (Figure 37)

79. COATING PROCESSES (Figure 48)

80. BONDING PROCESSES (Figure 50)

81. MECHANICAL FASTENING (Figure 53)

82. FORMING PROCESSES (Figure 30)

83. SEPARATING PROCESSES (Figure 36)

84. COMBINING (Figure 37)

85. MATERIAL PROCESSING (Figure 28)

86. MATERIAL PROCESSING (Figure 29) SCRIPT FOR

ADVANCE ORGANIZER II

MATERIAL PROCESSING: SEPARATING AND COMBINING

(1) In the (2) first video tape, you learned that materials are processed in three major ways: by forming, by separating and by combining.

(3) Forming processes were described in the f ir s t video tape.

(4) This video tape will focus on two groups: separating and

(5) combining processes.

(6) Separating processes remove excess material from the work­ piece. The correct size, shape and surface finish for a part are produced by carefully controlling the amount and location of material which is removed.

(7) Separating processes involve three basic principles: the use of a tool, the application of force to remove material, and control of the movement between the tool and the workpiece.

(8) Separating processes are either direct or non-direct.

(9) Direct separating processes use a solid tool. The tool comes into direct contact with the workpiece during the entire separating process.

185 186

(10) Direct separating processes can be classified into two

groups: shearing and chip removing.

(11) These processes are shearing processes. (12) Notice how the

blades separate the metal. No chips or waste materials are produced

(13) along the line of separation.

(14) These processes are chip removing processes. Waste material

in the form of chips, shavings, or (15) dust is produced by these (16)

routing, drilling, sawing, sanding and shaping operations. In each of

these cases, (17) force is applied directly to the workpiece by the

cutting tool, and chips, shavings, (18) dust or other waste is produced at the point of separation. (19)

(20) Chip-removing tools may have a single cutting edge, or several cutting edges.

(21) This hand plane is an example of a single-point cutting tool.

(22) The tool operates with a back-and-forth motion. As the plane moves along the board, waste stock is removed in the form of a shaving. (23)

The body of the plane controls the depth of each cutting stroke.

(24) The twist drill is an example of a multipi e-point cutting tool. This twist drill has two cutting edges.

(25) The rotating motion and the feed motion of the drill (26) cut a round hole in the piece of stock.

(27) The last subgroup of separating processes is non-direct separating. Here, the main characteristic is that the tool does not maintain continuous direct contact with the workpiece. 187

(28) There are two general types of non-direct separating pro­

cesses: fracturing and agent separating.

(29) Fracturing means breaking. Materials are often separated

by controlled breaking along a weakened area in the workpiece.

(30) Limestone is a naturally layered material. Some of the

layers are weaker than others. (31) Notice how this stone breaks along

a weak layer when struck with a hammer.

(32) Glass is cut by fracturing. (33) A line is scratched on the

surface to weaken the glass.

(34) When force is applied, the glass fractures along the weakened

area created by the scribed line.

(35) The other type of non-direct separating is agent separating.

Examples of agents are : high-temperature flames, electric arcs,

chemicals, sound waves, high pressure liquids, and high-intensity

light waves.

(36) This is electrical discharge machining. The tool is a piece

of printing type. The shape of the tool is machined into the piece of

steel (37) by electrical discharge.

(38) This flame cutting process uses heat, gas pressure, and

chemical burning to cut through this piece of steel. (39) The torch

tip controls the flame and gas, but does not come into direct contact with the steel.

(40) Remember this diagram? The last major group of material

processes is combining.

(41) Combining processes assemble or add materials together to make a completed product. (42) Combining processes are classified into four basic subgroups mixing, coating, bonding, and mechanical fastening.

(43) Mixing evenly distributes materials together.

(44) Clay and water are mixed together to make slip. First the clay is soaked in water. Then the mixture is stirred.

(45) Mulling sand is another common mixing process. Here, the rolling wheels of the muller mix water with foundry sand to give it the proper consistency.

(46) Other examples of mixing processes are: tumbling, shaking and vibrating.

(47) The next subgroup of combining processes is coating.

(48) Coating can be done in two general ways: by applying one material to the surface of another material, or by converting the surface of the material in some way.

(49) Examples of coating processes which apply one material to the surface of another are: spraying, brushing, dipping, and printing.

(50) A coating of glaze is being applied to this clay casting by brushing. The glaze could also be sprayed in place, or the clay article could be dipped in a container of glaze.

(51) A clear finish is being applied to this wood paddle.

(52) The last two subgroups of combining processes are bonding and mechanical fastening.

(53) Bonding means to unite materials or to make them one unit.

There are two basic groups of bonding processes: fusion bonding and adhesive bonding. 189

(54) Fusion bonding processes melt the surfaces of two materials; mix the melt together; and solidify the melt into one piece. Heat, pressure, and solvents are commonly used to bond materials together.

(55) Oxyacetylene welding is a good example of fusion bonding.

We are watching this process through a darkened lens to protect our eyes and the video tape equipment. The hot flame efficiently melts the two pieces of steel together. (56) Likewise, spot welding bonds metals together by fusion.

(57) Adhesive bonding processes use a glue-like material to hold parts together. The bonding material is called an adhesive.

(58) This dado jo in t could be bonded entirely by gluing. The glue would hold (59) the parts together without the nails if the joint was clamped until the glue set. Both surfaces of wood are coated with glue (60) before they are assembled.

(61) The last subgroup of combining processes is mechanical fastening.

(62) Mechanical fastening can be done in two basic ways: by using mechanical fasteners, or by shaping the parts so that they f it together.

(63) There are thousands of kinds of mechanical fasteners. Butt­ ons, shoe laces, nails and bolts are typical examples.

(64) The nails in this dado joint mechanically fasten the parts together.

(65) These wood screws mechanically fasten the parts of this butt joint together. 19Q

(66) This rolled sheetmetal joint is a good example of the second

type of mechanical fastening. The shape of the parts holds them to­

gether.

(67) First, one part of the joint is formed by the set of rollers

in this machine. (68)

(69) The other part of the joint is positioned under the rolled

bead.

Finally, the edge of the f ir s t part is bent over to lock the two

pieces together.

(70) This dovetail joint is fastened by a combination of the shape of the parts, and an adhesive bonding material. Before the joint

is glued, (71) it can only be taken apart by pulling in one direction.

The shape of the pieces mechanically 'fastens them together. (72)

(73) Let's quickly review the major groups of processes which we

have described. We have classified material processing into three

broad groups: forming, separating and combining.

(74) We then classified each broad group of processes into sub­ groups. We said that forming processes change the basic external or internal structure of the material. The structure is changed in one of three ways: by casting and molding, by compressing and stretching, or by conditioning.

(75) Separating processes remove material from the workpiece in a controlled way. They are either direct or non-direct.

(76) Direct separating processes include shearing and chip removing 191

(77) Non-direct separating processes include fracturing and

agent separating.

(78) Finally, we called processes which put materials together

combining processes. Combining processes were classified into four

subgroups: mixing, coating, bonding and mechanical fastening.

(79) Coating is done by applying a material or converting the

surface.

(80) Bonding is done by fusion or adhesion.

(81) Mechanical fastening is accomplished by usingmechanical

fasteners or shaping the parts in a particular way.

(82) With a knowledge of these basic concepts,(83) you should be able to understand any (84) material processing operation more easily.

(85) When you read about material processing in the future, try to think about how specific processes f i t into one of these groups. (86) SEPARATING —Tool U sed —Force Removes Material

—Tool Movement Controlled

Figure 38.

DIRECT SEPARATING

— Use a solid cutting tool

— Tool has one or more cutting edges

Figure 39. DIRECT SEPARATING

— S hearing

— Chip Removing

Figure 40.

Single-Point Tool Multiple-Point Tool

Figure 41. NON-DIRECT SEPARATING

Figure 42.

NON-DIRECT SEPARATING

- FRACTURING

- AGENT SEPARATING

Figure 43. FRACTURING — Breaking

Figure 44.

AGENT SEPARATING

— High temperature flames and gases.

— Electric arcs.

— Chemical solutions.

— Sound Waves

— High pressure liquids.

— High intensity light waves

Figure 45. MIXING PROCESSES

— Evenly distribute two or more materials together.

Figure 46.

MIXING PROCESSES

— Stirring

— Tum bling

— Mulling

— S haking

“ Vibrating

Figure 47. COATING PROCESSES

— Applying

— Converting

Figure 48.

COATING PROCESSES

— Spraying

— B rushing

” Dipping

— Printing

Figure 49. BONDING PROCESSES

— Fusion bonding

— Adhesive bonding

Figure 50.

FUSION BONDING

— Base materials flow together.

— Two parts become one material

Figure 51. ADHESIVE BONDING

— Adhesive material unlike base material is used.

■— Adhesive holds parts together.

F igure 52.

MECHANICAL FASTENING

~ Using mechanical fasteners.

Desigining shapes to fit together.

Figure 53. APPENDIX C

CONVENTIONAL OVERVIEW I

200 CONVENTIONAL OVERVIEW I

The content of Conventional Overview I is described in this

Appendix. This description is made up of two parts:

The first part of the description is a list of visuals which were used in the video tape. There were no block diagrams in the

Conventional Overview. There were, however, a number of signboards which showed the name of the process which was about to be demonstrated.

These are noted in the list of visuals but are not included as figures in the Table of Contents. The main visuals used in the Conventional

Overview were made up of a series of material processing demonstrations.

These demonstrations were video taped in color. Each visual segment of these demonstrations is numbered on the list which follows.

The second part of the description is a script which was put on the sound portion of the video tape. The demonstrations were described verbally as they were performed visually. The numbers from the lis t of visuals are included within the script to show how the visuals related to the script.

This video tape was ten minutes in length. Copies of the tape can be obtained by contacting the author.

201 LIST OF VISUALS*

FOR

CONVENTIONAL OVERVIEW I

1. MATERIAL PROCESSING

2. Forging hot steel in a trip hammer

3. Spinning aluminum on a spinning lathe

4. NATURAL MATERIALS

5. Various sizes of lumber

6. Parts of a wooden house frame

7. FOUNDRY WORK

8. MULLING SAND

9. Mixing water with sand in a muller

10. Closeup of amatchplate showing patterns

11. Closeup of other sideof pattern

12. SAND MOLDING

13. Two parts of a foundry flask with matchplate in position

14. Riddling foundry sand over the pattern

15. Ramming the sand mold ♦Items typed in capital letters were the signboards flashed on the video screen periodically. No block diagrams were used in the conventional overviews.

202 2Q3 CONVENTIONAL OVERVIEW I LIST OF VISUALS, continued

16. Cutting the sprue hole in the sand mold

17. Open mold showing the sprue hole and runner impression

18. Two halves of the sand mold showing the moldcavities

19. METAL CASTING

20. Aluminum ingots

21. Hot crucible furnace

22. Pouring molten aluminum into the sand mold

23. Opening the mold

24. Sawing runners off the aluminum castings

25. Belt grinding flash off aluminum castings

26. SHEETMETAL WORK

27. Stretchout drawing for a sheet metal box

28. Laying out the stretchout on the sheet metal with square and scriber

29. SHEARING SHEET METAL

30. Shearing sheet metal on the squaring shear

31. Back side of squaring shear as metal is cut

32. Notcher cutting out corners in sheet metal

33. Cutting corners of sheet metal with hand snips

34. BENDING SHEET METAL

35. Bending a hem on the box and pan brake

36. Bending the ends of a box on the box and pan brake

37. Bending the sides of the box on the boxand pan brake

38. SPOT WELDING 204

39. Spot welding the corners of the sheet metal box

40. JOINERY

41. BUTT JOINT

42. Two pieces of wood positioned for assembly

43. Laying out a line for drilling holes in the wood

44. Locating the position of the screw holes with an awl

45. Drilling shank holes for the screws

46. Countersinking the shank holes

47. Laying out the anchor holes for the screws

48. Drilling the anchor holes

49. Assembling the butt joint with screws

50. DADO JOINT

51. Laying out the dado joint

52. The dado head on the table saw

53. Cutting the dado on the table saw

54. Fitting the two parts of the dado joint together

55. Applying glue to the dado joint

56. Assembling the dado joint with nails

57. Setting the nail heads

58. DOVETAIL JOINT

59. The dovetail jig

60. Routing the dovetail joint

61. Fitting dovetail joints together CONVENTIONAL OVERVIEW I LIST OF VISUALS, continued

62. Closeup of dovetail joint parts

63. METAL SPINNING

64. Spinning lathe

65. Applying wax to the metal

66. Spinning aluminum

67. Completed spun items

68. Trimming the edge of the item on the lathe

69. Polishing the item with abrasive paper

70. Removing the spun item from the lathe

71. Completed spun items

72. CERAMICS

73. Pressing a pinch pot with clay

74. SLIP CASTING

75. Stirring slip

76. Open set of plaster slip casting molds

77. Pouring slip into the plaster molds

78. Top of mold after slip has begun to dry

79. Pouring excess slip out of the mold

80. Opening the plaster mold

81. MATERIAL TESTING

82. Breaking unfired clay with a hammer

83. Striking fired clay with a hammer

84. Hardness tester

85. Testing wood for hardness CONVENTIONAL OVERVIEW I LIST OF VISUALS, continued

86. Testing a second piece of wood

87. Filing a soft piece of steel

88. Filing a hard piece of steel

89. Mulling foundry sand

90. An open sand mold

91. Pouring aluminum into a sand mold

92. Opening the sand mold

93. Notching sheet metal

94. Bending sheet metal on a box and pan brake

95. Spot welding sheet metal

96. Dovetail routing

97. Metal spinning on a lathe

98. Oxyacetylene welding SCRIPT FOR

CONVENTIONAL OVERVIEW I

(1) (2) Industrial products and processes are a central part of our lives. (3) This video tape was designed to help you learn about how materials are processed into useful products.

(4) Some processes change materials from their natural state into standard stock.

(5) For example, wood is found as a living tree in its natural state. Special processes are used to change the tree into standard­ sized boards. Once cut into standard sizes, the boards are called standard stock.

(6) Other processes are used to change standard stock into useful products. Building a wood frame for a house is one example of how boards are converted into a finished product. This video tape focuses on several processes which change standard stock into useful products.

FOUNDRY WORK (.7)

(7) Casting is a very common industrial process. The parts which are produced by this process are called castings.

207 208

MULLING SAND (8)

(8) First, a mold is needed. (9) In this case, the mold is made from sand. Water is used to hold the sand particles together. The water is mixed with the sand in a mulling machine.

(10) A pattern is needed to produce the sand mold. This pattern was designed to produce several different parts at the same time - a sword, a shield, a boot, a propeller and a crank. (11) The pattern is mounted on a board called a match plate.

Half of the pattern is on each side of the board. The long bar in the middle will produce a path in the mold for the melted aluminum to get into the individual mold cavities.

SAND MOLDING (12)

(12) The pattern is placed (13) between the two parts of a metal fl ask.

Fine sand is (14) riddled or sifted over the pattern to produce a smooth surface next to the pattern.

(15) The sand is packed against the pattern.

(16) Sprue holes are cut in the sand to provide for an opening to the outside.

(17) The aluminum will be poured through this hole.

(18) The two halves of the mold are put together and the mold is ready for pouring the casting. 209

METAL CASTING (19)

(20) Aluminum ingots are used as standard stock.

(21) The ingots are melted in a crucible furnace.

(22) When the aluminum reaches the proper pouring temperature, the crucible is removed from the furnace, and the casting is poured.

(23) After the aluminum cools and solidifies, the mold is opened, and the castings can be removed.

(24) The individual castings are cut away from the runner. The runner and sprue can be remelted and used again.

(25) Any rough areas on the casting can be smoothed by belt grinding.

SHEETMETAL WORK (26)

(26) A large number of products are produced from sheet metal.

The next section of the video tape will show the basic steps used in producing a sheet metal box.

(27) The f ir s t step with most sheet metal projects is producing a pattern. This full-sized pattern was developed for a small sheet metal box. The pattern shows the various parts of the box and how they will fold together.

(28) After developing the pattern, the cutting and folding lines are laid out on a piece of sheet steel. A square and awl work well for this operation. 210

SHEARING SHEET METAL (29)

(29) Next the pattern is cut out. (30) The squaring shear works well for making the (31) first long straight cuts.

(32) A notcher can be used to cut away the waste material from

the corners of the pattern.

(33) Finally, the snips are used to finish cutting out the

pattern.

BENDING SHEET METAL (34)

(34) Next the metal must be bent into shape.

(35) First, a hem is bent along each of the outside edges.

Bending over a narrow strip along each edge of the pattern gives the

edges added strength and smoothness.

(36) Next, the ends of the box are bent. The tabs are bent at

the same time. A box and pan brake is used to bend the ends and sides

of the box.

(37) Finally, the sides are bent. The tabs are pushed inside

the box. The tabs will be used to fasten the ends and sides together.

SPOT WELDING (38)

(38) The tabs and sides are welded together by (39) spot welding.

Two welds at each corner will produce a strong joint.

JOINERY (40)

(40) It is important to select the right joints when designing a

product. Joints affect the strength of the product. They also 211 affect accuracy, appearance and ease of assembly.

BUTT JOINT (41)

(41) One of the simplest joints for assembling wood parts is the butt joint. (42) The ends of each piece are cut square. Screws or nails are commonly used to fasten the parts together.

(43) When using screws, i t is important to space them properly.

(44) The location of the screw is usually laid outon the wood with a pencil and square.

(45) Next, the proper sized shank holes are drilled. The hole should be big enough to allow the shank of thescrew to slide through the board.

(46) The top of each hole is countersunk to acconmodate the tapered shape of the screw head.

(47) Next, the pieces are put-together, and the holes are laid out on the end of the second piece of wood. An awl works well for this operation.

(48) The anchor holes in the second piece of woodmust be smaller than the diameter of the screw thread.

(49) When the proper sized holes are drilled, the parts are assembled by driving the screws into place.

DADO JOINTS (50)

(50) Dado joints are stronger than butt joints. They are easier to assemble, and the finished assembly is usually more accurate. 212

(51) First, the dado is laid out on the stock. The dado is usually

cut to a depth of one-half the thickness of the stock.

(52) A dado head is mounted on the table saw and adjusted to the

right height. (53) The several blades of the dado head make it possible to make a wider cut with each pass across the blades.

The dado can be assembled with glue only, glue and nails, screws, or other fasteners.

(54) The dado is cut and tested for correct size.

(55) Glue is applied to both surfaces of the joint. It is especially important to get a good coating on the end grain because end grain absorbs more tjlue.

(56) In this case, finishing nails are used to hold the joint together until the glue sets.

(57) Thenail heads are driven below the surface of the wood with a nail set. This makes it possible to hide the nail heads byfilling the holes with wood filler.

DOVETAIL JOINTS (58)

(58) The dovetail jo in t is often used on commercially produced furniture.

(59) It is pleasing in appearance, and has considerable strength.

(60) The joint is produced by using a special cutter bit in the router, and a special holding device and guide.

The two matching parts are clamped together in the special fix­ ture. Both matching parts are cut at the same time with the router. 213

The parts of the dovetail joint which fit together are shaped in a special way. (61) The shape tapers out in a manner similar to the shape of a dove's tail feathers.

(62) Notice how the completed parts fit together. When all of the parts for an assembly are cut to shape, the dovetail joints are commonly assembled with glue.

METAL SPINNING (63)

(63) Metal spinning is a fascinating process which changes fla t sheets of metal into cylindrical shapes. Aluminum pots and pans used in the kitchen are sometimes made by spinning.

(64) A special lathe is used for spinning. A special form is mounted on the spindle of the lathe. The metal disc is held against the end of the form by a ball-bearing center.

(65) Wax is applied to the metal to lubricate the surface and allow the steel tool to work back and forth smoothly.

The round end of the forming tool is forced against the spinning disc to shape i t over the form.

As you watch the process, (66) look for the tool moving back and forth on the underside of the form. Also watch the changes which are occurring in the disc.

As the tool is moved from the center to theoutside of the disc, the aluminum is stretched outward. When the tool is moved from the outside back toward the center, the aluminum is pushed back toward the form. Gradually, by working the tool back and forth, the flat disc is shaped against the form. 214

(67) At the end of the process, (68) the edge of the spun object is trimmed with a sharp tool.

(69) The outer surface of the spun article is polished with abrasive paper. Oil is used to make the abrasive cut more smoothly.

(70) Finally, the completed article is removed from the form.

(71) Spinning is an interesting process which can be used to produce a variety of shapes.

CERAMICS (72)

(72) Ceramic materials are widely used for industrial products.

(73) You have probably had some experience with clay in your art classes.

SLIP CASTING (74)

(74) Slip casting is a common industrial ceramic process.

(75) Clay can be cast in a mold ifit is f ir s t mixed with water to make a liquid called slip.

(76) Plaster molds are used.

(77) When the slip is pouredinto the mold, the water is absorbed by the plaster.

(78) This leaves a shell of solid clay near the surface of the plaster mold.

(79) When a sufficient thickness of clay is built up, the excess liquid can be poured out of the center of the mold. 215

(8U) After further drying, the mold is opened and the clay product is removed. When the product is completely dry, i t is fired in a kiln.

MATERIAL TESTING (81)

(81) When clay is fired in a kiln, i t gains hardness and strength.

(82) The hardness can be demonstrated by striking dried clay with a hammer, and then (83) striking fired clay. The fired clay does not break after repeated blows with the hammer.

(84) Other materials have varying degrees of hardness. (85) For example, one of these two pieces of wood is much harder than the other. The (86) speed at which the needle on this hardness tester moves, tells the hardness of the material. The faster and farther the needle moves, the softer the material.

(87) This piece of steel is harder on one end than on the other.

One end files easily. (88) The other end is barely affected by the file.

(89) We have looked at a number of common industrial processes.

(90) We watched the sand casting process, starting with mulling the sand and (91) finishing with a completed casting. (92)

(93) We described the steps necessary for producing a small sheet metal box. (94) (95)

(96) We also described the characteristics of a number of wood joints. (97) Finally, we demonstrated metal spinning.

(98) In the next video tape, we will explore additional common industrial processes. APPENDIX D

CONVENTIONAL OVERVIEW II

216 CONVENTIONAL OVERVIEW II

The content of Conventional Overview II is described in this

Appendix. This description is made up of two parts:

The first part of the description is a list of visuals which

were used in the video tape. There were no block diagrams in the

Conventional Overview. There were, however, a number of signboards which showed the name of the process which was about to be demon­

strated. These are noted in the list of visuals but are not included

as figures in the Table of Contents. The main visuals used in the

Conventional Overview were made up of a series of material processing

demonstrations. These demonstrations were video taped in color.

Each visual segment of these demonstrations is numbered on the list which follows.

The second part of the description is a script which was put

on the sound portion of the video tape. The demonstrations were

described verbally as they were performed visually. The numbers

from the list of visuals are included within the script to show how

the visuals related to the script.

This video tape was ten minutes in length. Copies of the tape

can be obtained by contacting the author.

217 LIST OF VISUALS*

FOR CONVENTIONAL OVERVIEW II

1. MATERIAL PROCESSING

2. Mulling foundry sand in a muller

3. An open sand mold showing cavities

4. Pouring aluminum into a sand mold

5. Opening the mold

6. Notching sheet metal on a notcher

7. Bending sheet metal on a box and pan brake

8. Spot welding sheet metal

9. The dovetail fixture for the router

10. Spinning aluminum on the spinning lathe

11. Oxyacetylene welding

12. EDM

13. Electro-discharge machining in operation

14. The completed EDM workpiece

15. SHEET METAL WORK

16. Rolling a sheet metal seam

*1terns typed in capital letters were the signboards flashed on the video screen periodically. No block diagrams were used in the conventional overviews.

218 CONVENTIONAL OVERVIEW II LIST OF VISUALS, continued

17. Rolling the rolled edge.

18. Closeup of the rolled edge

19. Putting the two parts of the seamtogether

20. Locking the seam together

21. The completed seam

22. OXYACETYLENE WELDING

23. The oxy-acetylene flame

24. Running a melt strip

25. Flame cutting a piece of steel

26. The finished edge of the flame cut steel

27. FORGING

28. Hot steel in the forging furnace

29. Hammering hot drill rod on the anvil

30. HEAT TREATING

31. Hot steel heating in theforging furnace

32. A quench bucket

33. Quenching hot steel

34. FINISHED PRODUCTS

35. A Jokari game

36. MACHINE WOODWORKING

37. The Jokari game

38. Layout of the paddle for the game

39. BAND SAWING

40. Band sawing the paddle for the game 220

CONVENTIONAL OVERVIEW II LIST OF VISUALS, continued

41. BELT SANDING

42. Sanding the edge of the paddle on the belt sander

43. ROUTING EDGES

44. Shaper table with router mounted, showing router cutter

45. Shaping the edges of the paddle

46. Brushing lacquer on the surface of the paddle

47. CERAMICS

48. Making a clay pinch pot

49. Pressing the clay into a plaster mold

50. Pinching clay—a closeup

51. Making a pinch pot

52. CUTTING GLASS

53. Scribing the glass

54. Applying pressure to break the glass

55. MATERIAL PROCESSING

56. Mulling sand

57. An open sand mold

58. Pouring aluminum

59. Opening the mold

60. Notching sheet metal

61. Bending sheet metal on a box and pan brake

62. Spot welding

63. Spinning aluminum on the spinning lathe 221

CONVENTIONAL OVERVIEW II LIST OF VISUALS, continued

64. Electro-discharge machining

65. A completed EDM part

66. Rolling a sheet metal seam

67. The completed sheet metal seam

68. Oxyacetylene welding

69. Flame cutting

70. Heating steel in the forging furnace

71. Forging steel

72. Quenching steel

73. Bandsawing

74. Belt sanding

75. Shaping on a wood shaper

76. Applying finish with a brush

77. Pinching clay

78. Cutting glass

79. MATERIAL PROCESSING SCRIPT FOR

CONVENTIONAL OVERVIEW II

MATERIAL PROCESSING

(I) (2) The first video tape on (.3) material processing

(4) presented a number of common industrial processes (5) which are used to change standard stock into (6) completed products. We (7) saw foundry work, (8) sheet metal work, joinery, and spinning.

This video tape (9) will present some (10) additional industrial processes.

(II) Several hot metal processes and several machine wood­ working processes will be shown.

E.D.M. (12)

(12) EDM stands for electro discharge machining. (13) Electric sparks between the tool and workpiece are used to remove metal from the workpiece. The heat from each spark melts away a small amount of metal. The workpiece is immersed in a fluid. As metal is removed, it is cooled and flushed away by the fluid.

222 223

(14) The shape of the tool determines the shape that will be machined away. In this example, pieces of printing type were used as the tool. The shapes of the letters were machined in the piece of steel.

This process is especially useful for machining very hard metals which are difficult to machine in other ways.

SHEET METAL WORK (15)

(15) An extensive amount of sheetmetal work (16) is used in construction. Some buildings have miles of sheet metal ducts.

A special seam is used to fabricate much of this duct work.

(17) To make the seam, one edge of the sheetmetal is fed through a rolling machine. (18) The rolls form a fold along the edge.

(19) The other part of the seam is bent at a right angle. It slides under the fold.

After sliding the two parts together, (20) the first edge is bent over the top, locking the seam together. (21)

OXYACETYLENE MELDING (22)

(23) You are watching oxyacetylene welding. Acetylene is a very good fuel. It burns at high temperatures when properly combined with oxygen. (24) The hot flame readily melts the two pieces of steel together.

(25) Flame cutting is often done with an oxyacetylene flame.

This process is widely used to cut steel. The oxyacetylene flame 224 preheats the metal. A je t of oxygen burns the heated steel and blows the burned material away.

(26) A skilled flame cutter can cut fairly smoothly. Flame cutting is much faster than sawing.

In some cases the torch movement is controlled by a machine rather than held by hand.

FORGING (27)

A good quality of steel must be used. (28) Forging processes are often used for making tools. Drill rod is a good material for making small tools. First the rod is heated to a red-hot temperature in a forgery furnace.

(29) Then the rod is hammered over an anvil. When the rod cools, it must be reheated. Sometimes the rod must be reheated several times.

The rod must be turned and hammered on all four sides to achieve the desired shape.

HEAT TREATING (30)

(30) Metals are heat treated in a (31) variety of ways. (32) One heat treating process is hardening. Basically steel is hardened in two heat treating steps. First the steel is heated to its hardening temperature. Second the steel is cooled very rapidly. (33)

The hardening temperature varies with the particular type of steel. Some types of steel are cooled in water. Other steels are cooled in cold air, o il, or salt brine. FINISHED PRODUCTS (34)

(35) This Jokari game was produced using a variety of processes

and materials. It was manufactured in a junior high school class.

MACHINE WOODWORKING (36)

(37) Several machine woodworking operations were used to make

the paddles for the game.

(38) First, a template or pattern was made. The template was

used to lay out the shape of the paddle on the standard stock.

BAND SAWING (39)

(40) A band saw was used to cut out the shape of the paddle.

The band saw is very useful for cutting curves and other irregular

shapes. The blade cuts continuously. It is much more efficient

than a scroll saw or sabre saw.

The work is guided so that the saw cuts on the outside or waste

side of the lay-out line.

Wider band saw blades can be used to cut around large curves;

a narrower blade is needed for cutting around smaller curves.

Several cuts have to be made at the end of the paddle because the

blade is too wide to turn the corner in the saw kerf.

The smoothness of the cut depends upon a number of factors.

Usually further processing is needed to finish the surface of wood which is cut on the band saw. 226

BELT SANDING (41)

The belt sander can be used to remove most of the saw marks le ft by the band saw. The large outside curve can be (42) sanded on the table of the belt sander. The inside curve must be sanded on a drum sander.

In order to produce a finished paddle of the right size, the operator must be careful not to sand beyond the layout line.

ROUTING EDGES (43)

If the paddle is to (44) function properly, the edges must be rounded over. It would be very difficu lt and time consuming to sand a (45) uniform rounded edge on the paddle.

The router is an ideal tool for this operation. In this case, the router is clamped into a special table called a shaper table.

The work is then maneuvered around this router belt on the table surface.

The router can be adjusted up and down in the shaper table.

This adjustment is one way of controlling the depth of cut.

A smooth guide pin on the end of the cutter bit rides against the edge of the paddle and also controls the depth of cut.

If the wood is moved too fast, the cutter bit will not cut smoothly. If the work is moved too slowly, the router b it will burn the wood.

The router bit is turning in a counter-clockwise direction as viewed from the top. Notice the direction the wood is fed against the bit. 227

(46) After the edges of the paddle have been routed, the paddle is hand sanded lightly and dusted. Then a finish is applied to seal the surface of the wood.

CERAMICS (47)

(48) Clay is usually not used in industrial arts classes in Iowa, but it is an important industrial material. It is (49) used as standard stock for many products. Flower pots, china cups, saucers, plates, the insulators on the spark plugs in your car, some watch bearings, phonograph needles, and synthetic jewels are made from various types of clay.

(50) Clay is very pliable. It can be shaped easily. This characteristic makes it very useful as a modeling material. During the design process, (51) clay models of a product are often made.

These models can be changed easily. They provide a three-dimensional perspective for the designer. Many cars are first created in clay.

CUTTING GLASS (52)

(52) Glass is another widely used industrial material. (53) Most industrial glass is produced as sheet stock. It must be cut to size before i t can be used.

First, the surface of the glass is scratched or creased with a glass cutter. (54) Then pressure is applied, and the glass breaks along the line where i t was scratched. 228

(55) In the first video tape, we saw several (56) material

processing operations. We saw mulling (57), molding, and pouring (58) of aluminum in the foundry. Next (60), we saw (61) several sheetmetal operations. We (63) saw how metal spinning is done.

In the (64) second video tape, we saw electrical (65) discharge machining. We (66) rolled a sheetmetal (67) seam. We (68) did oxyacetylene welding and (69) flame cutting. We (70) saw the process

(71) of forging . . . and (72) heat treating. We saw several machine woodworking operations: (73) band sawing, (74) belt sanding, and (75) shaping with a router. We (76) did some finishing. We (77) looked at some ceramic materials, and (78) saw how glass is cut.

(79) These processes are all-important to the production of products which we use everyday. APPENDIX E

READING I

229 READING I

Reading I contains the following topics: polymers, injection molding, extrusion, blow molding, compression molding, metals, forging, heat treating, and presswork. Except for page numbers and figure numbers, this reading is reproduced as i t was used in the experiment.

Page numbers and figure numbers have been changed to correspond with the sequence of pages and figures in the dissertation. Copies of letters which stipulate the conditions under which copyrighted illustrations were reproduced in this reading and replies granting permission to use the illustrations as stipulated are shown in Appendix I.

230 231

POLYMERS

Plastic materials are made of polymers. Polymers are very large molecules. These large molecules are made up of smaller parts called mers. The w ord poly m eans many. Polymer m eans many mers. When the mers link together, they form a long chain. Usually the center of this chain is made up of carbon atoms.

Some large molecules occur in nature. For example, wood is a natural polymer. Other polymers are made by chemists. These polymers are called synthetic (man-made) polymers. Most of the plastics we use are synthetic polymers. Synthetic polymers are produced in several forms. They are available as liquids, granules (beads), powder and rope.

There are thousands of polymers. All polymers can be classified into two groups. The two groups are thermoplastics and thermosets. Thermo m eans heat. Plastic m eans pliable. Set m eans to harden.

Thermoplastic polymers (thermoplastics) soften when they are heated and harden when they are cooled. While soft, the shape of a thermoplastic can be changed. Cooling causes the thermoplastic to keep its shape. If reheated, the shape can be changed again. Thermo­ plastics can be softened and hardened many times by heating and cooling.

Thermosetting polymers (thermosets) are just the opposite. They soften slightly, then harden when heated. They cannot be resoftened and reshaped once they have hardened. If too much heat is applied, a thermoset will char or bum. It will not resoften.

INJECTION MOLDING

Injection molding is a very common process. This process is mainly used with thermo­ plastic materials.

Special machines are used to injection mold plastic items. These machines have two basic parts. One part of the machine heats and injects the plastic. The other part opens and closes 54 a mold. Figure shows a drawing of a typical injection molding machine. 232

CLOSED DIE MOLDS FEED HOPPER

FEED SCREW

Figure 54INJECTI0N MOLDING

From TECHNOLOGY OF INDUSTRIAL MATERIALS Copyri^i 1974. by Kuvui it «l. Reproduced with permission, Bennett Publishing Co.

The hopper is filled with plastic beads (small pellets or granules). A screw forces the beads into a heating chamber. As the beads are heated, they become soft. At the right time, the screw forces the semi-liquid plastic through a nozzle into a mold.

Molds for injection molding are made of metal. They are usually made of two parts. Sometimes cold water is piped through the mold to keep the mold cool. As the plastic cools in the mold, it becomes solid. Then the mold is opened, and the part is removed.

Molds are expensive. They are made very accurately. The mold cavity is milled (cut) from a solid block of metal. The inside surfaces of the mold are highly polished. Very smooth parts are produced because of the high polish on the mold surface. Smooth surfaces also make it easy to get the part out of the mold.

Thousands of items must be molded to pay for the mold. Most parts of plastic car and airplane models are made by injection molding. Often several parts are molded together at one time. They must be cut apart before they can be assembled. EXTRUSION

If you have ever squeezed toothpaste out of a tube, you have some idea about how ex­ trusion works. The round opening of the tube is like an extrusion die. The round stream of toothpaste is like material coming out of an extrusion die.

The extrusion process is used to form thermoplastic polymers. It can also be used to ex­ trude metal, clay, glass, and other materials.

Figure55shows a typical plastic extruding machine. It is somewhat similar to the injection molding machine. Plastic is forced through a die opening. The shape of the opening deter­ mines the shape of the extruded material. The material continues to feed through the die. This produces a long piece of stock called an extrusion. A conveyor belt carries the molded plastic away from the die. As the extrusion moves away from the die, it is cooled by air or water. Cooling hardens the extrusion. The long extrusion is cut into standard lengths.

HOPPER

HEATERS

PRESSURE SCREW

Figure 5S EXTRUSION

From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Roproducad with permission. Bennett Publishing Co.

The extrusion process is used to make special shapes. Bricks are made by extruding clay into a long rectangular bar. A stiff wire is used to cut the bar into individual bricks. Plastic film can be made by extruding plastic through a die with a wide, thin opening.

BLOW MOLDING

T he blow molding process is used to make hollow objects. Thermoplastic polymers and glass are often blow molded into bottles and jars. Hollow plastic toys such as balls and dolls are made by blow molding. Plastic milk jugs are made by blow molding. 234

Figure 56shows how the blow molding process works. First, a soft hot tube of material is placed between the halves of a split (two-piece) mold. The mold is closed, sealing the tube at the bottom. Compressed air is forced into the tube. The air stretches the plastic tube and forces it outward against the sides of the mold. After the plastic cools, the mold is opened and the part is removed. Finally, the extra material at the top and bottom of the part is trimmed off.

Figure5 6 .BLOW MOLDING From MANUFACTURING PROCESSES Copyright 1973. by Johnson. Reproduced with permission, Bennett Publishing Co.

COMPRESSION MOLDING

Figure 57shows how the compression molding process works. First the mold is opened. A measured amount of thermosetting plastic is placed inside. The mold is closed. Heat and pressure are applied. The heat and pressure cause the plastic to soften, flow and fill the mold. Heat and pressure also cause a chemical change in the plastic. This chemical change hardens (cures) the plastic. After a short time, the mold is opened and the part is removed.

GRANULES

HEATED MOLD %

EJECTION

Figure 57COMPRESSION MOLDING From MODERN INDUSTRY Copyright 1976, by Wagner. Reproduced with permission, American Technical Society. Thermosets are usually molded by compression molding. Parts which must resist heat are made this way. Handles for fry pans, coffee pots, and toasxers are made this way. Ash trays are made by compression molding. 235

METALS

Metals are important industrial materials. They can be processed in many ways. They can be formed without breaking. They can be cast, welded, and machined.

Metals have several useful properties. They are often very strong. They support weight and resist bending. Some metals can be hardened or softened by heat treating. Waste metal can be remelted and used over in a new product.

Metals are classified into two basic groups. The two groups are ferrous and non-ferrous.

Ferrous metals contain iron. Non-ferrous metals have little or no iron content. Cast iron and steel are the main ferrous metals. Non-ferrous metals include aluminum, copper, zinc, tin and lead.

Most industrial metals are alloys. Alloys are mixtures. Two or more metals can be mixed to make an alloy. A metal and a non-metal can be alloyed.

The most important ferrous alloy is steel. Steel alloys are made of iron and carbon. Nickel, manganese, and tungsten are often used to alloy steel.

Brass is a common non-ferrous alloy. Brass is made by mixing copper and zinc. Zinc improves the strength and ductility (ability to be stretched) of brass.

The qualities of metals are changed through alloying. Carbon improves the strength of steel. Nickel keeps steel from rusting. Lead makes alloys easier to machine.

FORGING

Forging means hammering or squeezing metal into a certain shape. It is the most widely used method of hot-forming finished metal shapes. Forging can be done by hammering or pressing. Hammers deliver a great deal of impact pressure. Presses apply pressure more slowly, squeezing the material into the shape of a die. Hammer forgings are often rough. Press forgings are extremely accurate and have a very smooth finish. Figure58 shows how a drop hammer forging press works.

Forging changes the grain pattern of the material. Figure 59 shows some grain patterns for forged parts. 236

Ram

-Workpiece r Lower Die

Anvil

Rgut«58. FORGING PRESS

From TECHNOLOGY OF INDUSTRIAL MATERIALS Copyright 1974, by Kesanas at ai. Reproduced with permission, Bennett Publishing Co.

Y

•V - •’ v ,v a a • . VL L A A . '• M A

Figure 59. GRAIN PATTERNS MADE BY FORGING

From MANUFACTURING PROCESSES Copyright 1979, by Johnson. Reproduced with permission, Bennett Publishing Co.

Parts with forged grain patterns are stronger than parts made by other processes. Forged parts have greater strength and resistance to impact. Parts which must be very strong are usually forged. Examples are engine crankshafts, and quality tools. Figure 60. STEPS IN FORGING A CONNECTING ROD From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co. Figure 60 shows the steps in forging a connecting rod for an automobile engine. The rod starts as a round blank of metal at A. Each die changes the shape a little. At E the rod is nearly finished. At F, the extra material has been removed from the rod.

Many items are cold-forged. The heads of nails, screws, and fasteners are usually cold- forged. Cold-forged parts usually begin as a piece of wire or rod. See Figure 61.

The end of the wire or rod is struck by the forging die. This makes the end larger and forms a head. Figure 62shows how bolts are cold-forged.

e

Figure61. COLD-HEADING PROCESS From TECHNOLOGY OF INOUSTRIAL MATERIALS Copyright 1974, by K u n o « p. Roproducad with pormiuloo. Bannatt PubHahing Co. Figure62. STEPS IN FORGING A PART

From MANUFACTURING PROCESSES Copvri^ii 1973. by JoiUMoa. RspreduMd mih parmiwwn. S.w m i PiMaMag Cm.

HEAT TREATING

Heat treatment changes the internal properties of metals. Hardness, strength, and tough­ ness can be changed by heat treating. All heat treating processes involve controlled heating and cooling.

Annealing is a common heat treating process. Annealing softens or reduces the hardness of metal. To anneal a piece of steel, the metal is heated until it is red h o t Then it is cooled very slowly.

Steel is oftened hardened. Hardening improves strength and resistance to wear. Hardening involves two steps. First the steel is heated until it is red hot. Then the steel is cooled rapidly by quenching. Quenching means putting the hot metal into water, oil, salt brine, or cold air. This cools the steel rapidly. After quenching, the steel has a very fine grain structure. This structure makes the steel hard and brittle. It will fracture or break easily if left in this condition. Therefore, an added heat treating process called tempering is usually done.

Tempering slightly reduces the hardness of the steel. Tempering improves toughness and resistance to fracturing. This process is usually done right after hardening. The steel is heated to a temperature which is lower than the hardening temperature. Then the steel is cooled. 239

PRESSWORK

Presses are commonly used to cold-work metals. Presses exert tons of pressure on the workpiece. Therefore, they are usually very large machines. Most press operations are used on sheet stock.

Figure63shows the basic parts of a press. One of the basic parts is the drive mechanism. This may be a flywheel, a hydraulic cylinder, or some other device.

FLYWHEEL

GUIDE

FRAME

Figure 6 3.PARTS OF A PRESS

From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co.

A second important part is the ram. This part moves up and down and applies pressure to the work. Part of the die may be attached to the bottom end of the ram.

T he die holds the workpiece and shapes the work. The type of die used determines the type of work that can be done.

Figure64 shows a punch and die used for a blanking operation. This operation shears (cuts) a piece of material (a blank) from a larger piece of stock. The shape of the punch and die determines the shape of the blank. This process could be used to make washers for bolts.

Figure65shows a shell drawing process. A flat piece of metal is held by the pressure pad. The punch forces the metal into the die. The metal is drawn into a shell-like shape. 240

RAM

PUNCH

STOCK

CHE

•am BLANK Fiqure64.BLANKING OPERATION From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co.

PUNCH PRESSURE PAD L

DRAWN PART

Figure65.SHELL DRAWING WITH MATCHED DIES From METALWORK TECHNOLOGY AND PRACTICE Copyright 1976, by Ludwig, McCarthy and Rapp. Reproduced with permission, McKmght Publishing Co. Figure 66 shows another press operation called embossing. Most of the street signs you read on your way to school are formed by embossing. Auto license plates are made by em bossing.

When sheet metal must be bent in a straight line, a brake is used. The press brake is used for a variety of bending operations. The shape of the die determines how the material will be bent. 241

PUNCH

DRAWN PART

Figure6 6 . EMBOSSING From METALWORK TECHNOLOGY AND PRACTICE Copyr ight 1975, by Ludwig, McCarthy and Rtpp. Reproduc'd with p'rmiuion, McKnight Fubli'hing Co. Figure67 shows a set of typical dies for the press brake. Note how the workpiece springs back slightly when the punch is raised.

SPRINGBACK

Figure67. BENDING ON A BRAKE

From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co. APPENDIX F

READING II

242 READING II

Reading II contains the following topics: arc welding, resistance welding, gas welding, brazing and cutting, flame cutting, drawing, gluing, the lathe, drilling, threaded fasteners, milling, and grinding. Except for page numbers and figure numbers, this read­ ing is reproduced as it was used in the experiment. Page numbers and figure numbers have been changed to correspond with the sequence of pages and figures in the dissertation. Copies of letters which stipulate the conditions under which copyrighted illustrations were reproduced in this reading and replies granting permission to use the illustrations as stipulated are shown in Appendix I.

243 244

ARC WELDING

Welding is used to join two pieces of metal. First the pieces are put side by side. Then the surfaces of the two pieces are melted together.

Arc welding uses an electric arc (spark) which produces a temperature of about 9,000 degrees F. The heat from the arc melts the metal on each side of the joint and causes it to flow together. The electrode gradually melts and adds filler material to the weld. When the metal cools, the two pieces become one solid piece. See Figure 68. Notice the electrode, arc stream and molten metal.

ARCSTREAM

MOLTEN METAL . WELD B A SE M E T A L

Figure68. ARC WELDING

From ARC WELDING Copyright 1977, by Welker. Reproduced with permission, Goodheart*Willcox Co.

RESISTANCE WELDING

Resistance welding combines heat and pressure to join materials. Figure69 shows the four steps of the resistance welding cycle.

APPLICATION OF W ELD TIME FORGING TIME RELEASE OFELECTROOC ELECTRO DC FORCE

Figure69. RESISTANCE WELDING From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co. 245

Two copper electrodes are used. The electrodes are brought into contact on opposite sides of the material being welded. Electric current flows from one electrode, through the metal, to the other electrode. The current produces heat and melts the spot where the pieces are being welded. Pressure is applied to squeeze the softened metals together. When the metal cools, the pressure is released.

Resistance welding is used to join thin metals together. Auto bodies are welded together using this process. Spot welding and seam welding are two types of resistance welding. Spot welding produces welds in spots. Seam welding produces a continuous weld.

GAS WELDING

Gas welding processes use burning gases to heat the metal. Often a mixture of acetylene and oxygen is used. Acetylene gas is the fuel. Oxygen gas makes the fuel bum. These gases burn at a temperature of about 6,300 degrees. F.

The heat melts the surface of materials. The melting metal forms a puddle. The puddle is moved back and forth across the two pieces to join the metal. See Figure 70.

Filler material must sometimes be added to the joint. Often a bare filler rod is melted into the puddle. The filler rod is made of the same material as the piece being welded.

^ TORCH

FILLER ROD^

Figure 7 0 . GAS WELDING From OXYACETYLENE WELDING Copyright 1976, by Baird. Reproduced vuth permimon, Goodheert-WilicoM Co. 246

BRAZING & SOLDERING

Brazing is often used to join metals together. A bronze filler rod is used. The melting point of the bronze rod is lower than the melting point of the base metal (pieces being joined). When brazing, the base metal is not m elted.

As the base metal is heated, the filler rod melts. The melted filler material flows into the joint. The filler material sticks to the hot base metal. When the joint cools, the base pieces are adhered (stuck together) by the filler material.

Soldering is similar to brazing. Less heat is needed for soldering. Most solder is made of tin and lead.

Brazing and soldering materials both work like glues. Brazing and soldering materials adhere (stick) to the surfaces of the base metal.

FLAME CUTTING

The oxyacetylene (oxygen and acetylene) flame can be used lor flame cutting. A special torch is used for cutting. First, the base metal is preheated. A stream of oxygen is pointed toward the preheated steel. The oxygen causes the steel to burn. The burning steel is blown away by the stream of oxygen. Flame cutting can be used to cut thick pieces of steel.

DRAWING

Large sheet metal parts are often made by stretch drawing. Automobile fenders and hoods are made by this process. Figure 71 shows how this process works.

Gripper Jaws Upper Oie

Lower Oie Figure7 1 . STRETCH DRAWING From TECHNOLOGY OF INDUSTRIAL MATERIALS Copyright 1974. by K im p m at al. Reproducad with parmiwion. Banoatt Publishing Co. 247

The gripper jaws hold the edges of the sheet metal. The upper die forces the metal into the lower die. The metal is stretched into a new shape in the process.

PUNCH PRESSURE ON BLANK BY HOLDING RING

SS L B LA N K ^H O L D IN G W&W, *'NG

BLANK 1 WORK PARTIALLY DRAWN DRAW RING Figure 72.DEEP DRAWING

From MANUFACTURING PROCESSES Copyright 1973, by Johnson. Reproduced with permission, Bennett Publishing Co.

Another drawing process is shown in Figure 72. This process is used todeep-draw parts.

Wire is made by drawing a rod through a die. Figure 73 shows a wire die. Each hole in the die is a different size. First the rod is drawn through the largest hole. Then it is drawn through each smaller hole. Gradually the rod is stretched into a wire. Drawing the metal through the die changes the grain structure. The changed grain structure makes the wire strong.

WIRE DRAWING DICx

t PULL

Figure 73. DRAWING WIRE

From METALWORK TECHNOLOGY AND PRACTICE Copyright 1975, by Ludwig, McCarthy end Repp. Reproduced with permission. McKnight Publishing Co. 248

Pipe can be made by drawing fiat metal through a bell-shaped die. See Figure 74. After the pipe is shaped, the seam is welded.

BELL FLAT METAL

PIPE

Figure 74. DRAWING PIPE From METALWORK TECHNOLOGY AND PRACTICE Copyright 1975, by Ludwig. McCarthy and Rapp. Reproduced with perm iuion, McKnight Publishing Co.

GLUING

Glues are very important materials. Sometimes it is easier to join parts with glue than with other materials. No holes have to be drilled. Holes in one part do not have to line up with holes in another part. No tightening of fasteners is needed. Glue can be applied very rapidly. Newer glues set or cure (harden) very quickly.

Glues adhere (stick) to many different kinds of materials. Wood and metal can be glued together. Plastics and ceramics can also be glued together. When two different types of material are assembled, glues are often used.

Glues make very strong joints. Some glued joints are flexible. They will remain tight even when the base material changes size and shape.

Large surfaces are easy to glue together. Plywood is made of several layers of thin materi­ al. By gluing these thin layers together, a very strong material is made. 249

THE LATHE

The lathe is the oldest machine tool. It can be used to do many operations. Wood, metal, and plastic can be machined on a lathe.

Turning is a basic lathe operation. The workpiece (stock being cut) is revolved between two centers. As the work turns, a cutting tool is moved from side to side (right to left). As the tool moves against the turning workpiece, it cuts away shavings. See Figures 75and76.

TAJkvrocft i p i w l c ^0C*O CCNTCJI/ ,

Figure75. TURNING ON A LATHE

From METALWORK TECHNOLOGY AND PRACTICE Copyright 1975. by Ludwig. McCarthy and Rapp. Reproduced with ptrmiuion, McKnighr Publishing Co.

TOOL FEEDS Figure 7 6 .MOVEMENT OF THE TOOL AND WORKPIECE ON A LATHE From MODERN INDUSTRY Copyright 1975. by Wagnar. Reproduced with permission, American Technical Society. 250

Boring is another lathe operation. Boring produces a round hole in the workpiece. A boring bar is used as a cutting tool. The movement of the tool is similar to that of turning. A bored hole is cut more accurately than a drilled hole. See Figure 77.

CHUCK WORKPIECE - CUTTER BIT /-BORED SURFACE

BORING BAR

Figure7 7 . BORING ON A LATHE From MACHINE TOOL TECHNOLOGY Copyright 1966, by McCarthy and Smith. Reproduced with permission, McKmghi Publishing Co. Facing is another important lathe operation. The work is held in a chuck. As the work turns, the cutting tool moves along the end. See Figure 78. Note the direction the tool is moving. Facing produces a flat surface on the end of the stock.

WORK FACED ENO

I

Figure 7 8 . FACING ON A LATHE From METALWORK TECHNOLOGY AND PRACTICE Copyright 197S, by Ludwig, McCarthy and Repp. Reproduced with permission, McKmght Publishing Co. 251

A taper can be cut by moving the tool in an angular direction. See Figure 79. Notice the direction of the tool movement in the tapering operation.

Drilling, reaming, and threading can be done on a lathe. These operations require special accessories.

TAPERED SURFACE

Figure 7 9 .TAPERING ON A LATHE From MACHINE TOOL TECHNOLOGY Copyright 1968, by McCarthy and Smith. Reproduced with permission, McKntght Publishing Co.

DRILLING

Drilling machines are usually used to drill round holes. Most drills are twist drills. Usually twist drills have two cutting edges. The cutting edges remove small Chips (shavings! of metal as the drill is fed through the stock. The twisted flutes (grooves) of the drill remove chips from the hole. Drilling is not as accurate as boring. See Figure80.

Other operations can be done on drilling machines. See Figure 81.

Reamers are used to finish holes which have been drilled or bored. Reaming operations are more accurate than drilling and boring. Reamers improve the roundness of the hole. Reamers also improve the surface finish (smoothness) of the hole. 252

Figure8 0 . DRILLING A HOLE. Note how chips are removed. From MACHINE TOOL TECHNOLOGY Copyright 1968, by McCarthy and Smith. Reproduced with permission, McKnight Publishing Co.

DRILLING REAMING

Figure 8 1 .OPERATIONS WHICH CAN BE PERFORMEO ON A DRILL PRESS

From METALWORK TECHNOLOGY AND PRACTICE Copyright 197S, by Ludwig, McCarthy end Repp. Reproduced with permission, McKnight Publishing Co.

Reamers have several cutting edges. Each cutting edge takes off a small chip. Figure82 shows a typical reamer. Reamers can be used by hand or in machine tools. 253

DRILL PRESS SPINDLE•EH Ik LATHE CENTER _JT-Tjr /-TAP WRENCH

HAND REAMER 4072

Rgure82. BEAMING A HOLE From METALWORK TECHNOLOGY ANO PRACTICE Copyright 1975, by Ludwig. McCarthy and Rapp. Raproducad with parmcuion, McKnight Publithing Co.

THREADED FASTENERS

Threaded fasteners are widely used to assemble parts. Friction on the screw thread holds the parts together. Threaded fasteners have several advantages. They can be used to exert great pressure. The assembly is not permanent. It can be taken apart.

Figure 83 shows several types of threaded fasteners. How many have you seen before? Find th e machine bolt, cap screw s, machine screws, and wood screws.

Woodscrews have more holding power than nails. They take more time to install than nails. Woodscrews thread their way into the material. The material should be drilled before assembly. It does not have to be threaded.

Machine bolts are general purpose fasteners. They have a square or hex head which is tightened with a wrench. Machine bolts are assembled with a nut. Bolted joints are easy to take apart.

Machine screws are similar to bolts. Some machine screws are used with a nut. If threads are precut into the parts, machine screws can be used without a nut. Machine screws are generally small in diameter-smaller than bolts. 254

wooo SCREW OVAL HEAD ROUND HEAD FLAT HE AO

MACHINE •OLT

MACHINE SCREWS ■ 6 m i0 OVAL FILLISTER ROUND FLAT HEAD HEAO HCAO HEAD

CAR SCREW:

HEXAGONHCAO r,hyiT>tRRMrlin HE AO HEAO 0 FLAT £UAT

Figure8 3 . TYPES OF THREADED FASTENERS From METALWORK TECHNOLOGY AND PRACTICE Copyright 1975, by Ludwig, McCarthy and Rapp. Reproduced with permission, McKnight Publishing Co. Cap screws are generally hardened for extra strength. They are similar to bolts but are made more accurately. Cap screws are threaded directly into the prethreaded parts. No nut is used. Hardened cap screws can be tightened very tightly. The are less likely to vibrate loose. Cap screws are used to assemble some auto engine parts.

Sheet metal screws look like woodscrews. They have larger heads and sharper threads. Sheet metal screws are called self-tapping screws because they make their own threads in the material. Sheet metal screws are used to join thin sheets of metal.

MILLING

Milling can be used to cut flat or curved surfaces. Milling can also be used to hollow out internal areas for a die or mold. Milling is used to cut special shapes like gears.

Milling can be done on several machines. It is usually done on a milling machine. Two basic types of milling machines are horizontal and vertical m achines.

Figure 84 shows how the horizontal milling process works. A cutter with several teeth is used. A rotating cutter is mounted on a horizontal shaft. The workpiece is clamped to a moving table. The moving table feeds the work into the cutter. The teeth of the cutter peel away chips from the workpeice. 255

ROTATION

WORKPIECE

FEED

Figure 84.H0RIZ0NTAL MILLING From METALWORK TECHNOLOGY ANO PRACTICE Copyright 1975. by Ludwig. McCarthy and Rapp. Reproduced with permission, McKnight Publishing Co.

Vertical milling machines operate in a similar way. The cutters are mounted on a vertical shaft. Figure 85 shows some examples of vertical milling operations. Notice the movement of the cutter and workpiece.

Vertical milling machines can be used to do other operations such as drilling.

The milling process is a very precise and controlled process. It can be used to do very accurate machining. Wood, metal and plastic can be milled. Milling machines are heavy, and are strongly built. This allows hard materials to be machined accurately.

End milling of ktywiys Slab surfaca nulling Figure8 5 . VERTICAL MILLING Fomeoco.

From MANUFACTURING PROCESSES Copyright 1973, by Johnaon. Raproducad with parmiuion, Bannatt Pubiiahing Co. 256

GRINDING

Grinding wheels are made up of thousands of abrasive grains (small particles). The abra­ sive grains are very hard. They are glued together to make grinding wheels. Each abrasive grain is sharp and acts like a cutting tooth. Figure86 shows how abrasive grains cut.

A grinding wheel is like a cutter with many teeth. The size of the abrasive grains deter­ mines the size of the chips removed from the workpiece. Large abrasive grains act like large teeth and remove larger chips. This leaves a rough surface on the workpiece. Smaller abrasive grains remove smaller chips. This leaves a smoother surface. Abrasive grains are much smaller than the teeth on other cutting tools. A fine grinding wheel can produce a very smooth cut.

The grinding process is used in several ways. Rough grinders are often used to prepare metal for welding. Rough grinders are also used to remove the rough edges from metal castings when they come out of the mold. Precision grinders are used to cut stock to very accurate size. Precision grinders produce very smooth surfaces.

Grinders can cut very hard materials. Many tools are sharpened by grinding. Hardened cutting edges can be sharpened very accurately by grinding.

ABRASIVE GRAINS

CHIPS FROM WORKPIECE

LIGHT SPACES INDICATE VOIDS WORKPIECE

Figure8 6 . HOW A GRINDING WHEEL CUTS

From MANUFACTURING PROCESSES CopyriQht 1973, by Johnson. Reproduced with permission, Bennett Publishing Co. APPENDIX 6

CRITERION TESTS

257 258

KEYED RESPONSES FOR MATERIAL PROCESSING, FORM 5

Item Keyed Response Item Keyed Response

1 3 30 4 2 2 31 1 3 3 32 2 4 1 33 2 5 4 34 3 6 4 3b 4 7 4 36 2 8 2 37 Z 9 4 38 1 10 2 39 3 11 1 40 4 12 4 41 3 13 4 42 3 14 4 43 1 15 4 44 3 16 2 45 2 17 1 46 2 18 4 47 2 19 2 48 4 20 3 49 2 21 4 50 3 22 1 51 3 23 4 52 2 24 1 53 1 25 3 54 3 26 1 55 1 27 1 56 4 28 3 57 1 29 4 58 4 Material Processing Test Form 5

1. A premeasured amount of p la stic is put into the mold before the mold is closed. In which process does th is happen?

A. Injection molding B. Extrusion C. Dompression molding D. All of the above

2. Hammering or pressing hot metal between dies at a high pressure is called

A. Drawing B. Forging C. Welding D. Heat treating

3. The best way to cut a square piece of thin sheet stock would be

A. Drilling B. Boring C. Blanking D. M illing

4. Flame cutting is often used on

A. Iron and steel B. Thin sheet metal C. Aluminum D. Tin and lead

5. Metals warp out of ishape when heated unevenly. The best process for joining metals without warping would be

A. Arc welding B. Oxyacetylene welding C. Brazing D. Gluing

259 260 6. In the injection molding process

A. The material is placed on a conveyor belt B. Sand is injected into the form of amold C. Air pressure forcesthe material against the side of the mold D. The material is forced into ametal die or mold

7. Most plastic bottles are made by

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

8. The main purpose of heat tre a tin g is

A. To change the shape of a material B. To change properties such as hardness and strength C. To make a metal alloy D. To improve the appearance of the material

9. The process which heats the metal to the lowest temperature is

A. Arc welding B. Gas welding C. Brazing D. Soldering

10. Forming a f l a t piece of metal in to pipe by pulling i t through a die is an example of

A. Forging B. Drawing C. Braking D. Extruding

11. All of the following processes use dies or molds except

A. Milling B. Forging C. Drawing D. Injection molding

12. The best process for producing long pieces of stock would be

A. Injection molding B. Compression molding C. Blow molding D. Extruding * 261

13. Metal alloys can be made of

A. A mixture of two or more metals B. A mixture of a metal and a non-metal C. A combination of metals and non-metals D. All of the above

14. Glues can be used to assemble

A. Two wood pieces B. Two plastic pieces C. P la stic , metal and wood D. All of the above

15. Which of the following assemblies can be taken apart?

A. Assemblies with wood screws B. Assemblies with cap screws C. Assemblies with machine bolts D. All of the above

16. The grinder makes a smooth surface onmetal by

A. Heating the surface until it melts and runs B. Removing very small chips C. The grindstone hammers against the metal D. None of the above

17. Which process would not be used to produce a round hole on a metal lathe?

A. Turning B. Boring C. Reaming D. Drilling

18. All polymers are

A. Natural or synthetic B. Thermoplastic or thermosetting C. Large molecules D. All of the above

19. A process which forms metal by hammering is

A. Drawing B. Forging C. Casting D. Heat treating 262

20. A lathe operation which produces a round cylinder is

A. Facing B. Tapering C. Turning D. Boring

21. Which process changes the grain structure of metal?

A. Forging B. Heat treating C. Drawing D. All of the above

22. The word therm osetting means

A. The material hardens when heated B. The material softens when heated C. The material is a synthetic material D. The material is a natural material

23. Alloying is done to improve

A. Hardness B. Strength C. Ease of machining D. All of the above

24. Glues fasten materials together by

A. Adhering the pieces together B. Melting the pieces together C. The use of friction D. Mechanical force

25. The best tool to cut a very hard material would be

A. A grinding wheel B. A milling cutter C. A drill bit D. A blanking die

26. Which process is most like press forging?

A. Compression molding B. Injection molding C. Blow molding D. Extrusion 263

27. Screws which make their own threads in the workpiece are

A. Sheet metal screws B. Cap screws C. Machine screws D. All of the above

28. Thermosetting polymers are usually processed by

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

29. Which is an example of a drawn part?

A. a s tre e t sign B. An engine piston rod C. A good quality wrench D. A steel pipe

30. Drilling can be done

A. On a d rill press B. On a lathe C. On a milling machine D. On all of the above

31. The heads of nails and screws are formed by

A. Cold forging B. Drawing C. Hot forging D. M illing

32. P la stic parts fo r e le c tric fry pans would be made of

A. Thermoplastic materials B. Thermosetting materials C. Either thermoplastics of thermosets D. Polymers

33. Thermosetting materials are most often formed by

A. Injection molding B. Compression molding C. Extrusion D. Blow molding 264

34. Cutting out an irre g u la r shape from sheet metal would probably be done on

A. A press brake B. A draw die C. A blanking die D. A forging die

35. What process would most lik e ly be used to make a pop bottle?

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

36. The main ingredients of steel are

A. Copper and zinc B. Iron and carbon C. Tin and lead D. Aluminum and s ilv e r

37. The main purpose of this process is to change the grain structure of the metal

A. Forging B. Heat treating C. Drawing D. M illing

38. An operation on a lathe which produces a flat surface on the end of the workpiece is

A. Facing B. Reaming C. Turning D. Boring

39. Which of the following can exert the most pressure?

A. Wood screws B. Sheet metal screws C. Machine bolts D. Machine screws

40. What process is used to make hollow plastic toys?

A. Injection molding B. Extrusion C. Compression molding D. Blow molding 265

41. Which of the following terms refers to getting the proper hardness?

A. Annealing B. Quenching C. Tempering D. Forging

42. Spot welding melts metal using

A. An electric arc B. A gas flame C. Electric current D. None of the above

43. If several different kinds of materials have to be put together into one piece, the best process to use would be

A. Gluing B. Welding C. Brazing D. Soldering

44. If some parts of a product must be taken apart and put back together often, they should be held together by

A. An adhesive B. Nails C. Threading fasteners D. Brazing

The internal cavity of a die would probably be finished by

A. Turning B. Grinding C. Embossing D. Braking

The word synthetic means

A. Polymer B. Man-made C. Thermoplastic D. Thermosetting

The most commonly used method of hot forming metal shapes is

A. Drawi ng B. Forging C. Brake bending D. Blanking 266 48. Which material can be machined on a lathe?

A. Wood B. Metal C. P lastic D. All of the above

49. Which type of m aterial can be softened and reshaped over and over again?

A. All thermosetting materials B. All thermoplastic materials C. All natural materials D. All synthetic materials

All ferrous metals contain

A. Tin B. Lead C. Iron D. Zinc

51. Toughness and fracture resistance of hardened metal can be improved by

A. Annealing B. Quenching C. Tempering D. Forging

52. Grinding is most like

A. Milling B. Sanding C. Turning D. Drilling

53. Forging a part changes the grain structure of the metal. This change

A. Makes the part stronger B. Makes the part weaker C. Does not change the strength of the part D. Gives the part a grainy surface

5 4 . Large sheet metal parts such as car fenders and refrigerator doors are formed by

A. Forging B. Brazing C. Draw forming D. Welding 267

55. A threaded fastener which is usually used with a nut is

A. Machine bolt B. Sheet metal screw C. Cap screw D. All of the above

56. Which of the following could be machined on a milling machine?

A. Wood B. Metal C. P la stic D. All of the above

57. Straight line bending is done by

A. Brake bending B. Drawing C. Forging D. Blanking

58. A p la stic bag can be sealed by heating and pressing the seam. This process is most like

A. Gas welding B. Gluing C. Arc welding D. Spot welding 268

KEYED RESPONSES FOR MATERIAL PROCESSING, FORM 6

Item Keyed Response Item Keyed Response 1 3 30 2 2 1 31 3 3 3 32 3 4 2 33 4 5 4 34 1 6 1 35 4 7 3 36 2 8 3 37 4 9 1 38 2 10 1 39 2 11 2 40 4 12 4 41 1 13 1 42 3 14 4 43 2 15 4 44 4 16 3 45 2 17 1 46 3 18 4 47 1 19 3 48 3 20 1 49 2 21 1 50 1 22 2 51 3 23 4 52 4 24 2 53 2 25 4 54 1 26 4 55 3 27 1 56 2 28 2 57 2 29 4 58 3 269

Material Processing Test Form 6

1. Thermosetting polymers are usually processed by

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

2. Glues fasten materials together by

A. Adhering the pieces together B. Melting the pieces together C. The use of friction D. Mechanical force

3. A lathe operation which produces a round cylinder is

A. Facing B. Tapering C. Turning D. Boring

4. The grinder makes a smooth surface on metal by

A. Heating the surface until it melts and runs B. Removing very small chips C. The grindstone hammers against the metal D. None of the above

5. Metal alloys can be made of

A. A mixture of a metal and a non-metal B. A mixture of two or more metals C. A combination of metals and non-metals D. All of the above 270

6. Forging a part changes the grain structure of the metal. This change

A. Makes the part stronger B. Makes the part weaker C. Does not change the strength of the part D. Gives the part a grainy appearance

7. Metals warp out of shape when heated unevenly. The best process for joining metals without warping would be

A. Arc welding B. Oxyacetylene welding C. Gluing D. Brazing

8. In which process is a pre-measured amount of p la stic put into the mold before the mold is closed?

A. Injection molding B. Extrusion C. Compression molding D. All of the above

9. Which process is most like press forging?

A. Compression molding B. Injection molding C. Blow molding D. Extrusion

10. The word therm osetting means

A. The material hardens when heated B. The material softens when heated C. The material is a synthetic material D. The material is anatural material

11. A process which forms metal by hammering is

A. Drawing B. Forging C. Casting D. Heat treating

12. Glues can be used to assemble

A. Two wood pieces B. Two plastic pieces C. Plastic, metal and wood pieces D. All of the above 271

13. All of the following processes use dies or molds except

A. M illing B. Forging C. Drawing D. Injection molding

14. Which of the following assemblies can be taken apart?

A. Assemblies with wood screws B. Assemblies with cap screws C. Assemblies with machine bolts D. All of the above

15. Most plastic bottles are made by

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

16. The best way to cut a square piece of thin sheet stock would be

A. Drilling B. Boring C. Blanking D. Milling

17. The best tool to cut a very hard m aterial would be

A. A grinding wheel B. A milling cutter C. A drill bit D. A blanking die

18. All polymers are

A. Natural or synthetic B. Thermoplastic or thermosetting C. Large molecules D. All of the above

19. Large sheet metal parts such as oar fenders and refrigerator doors are shaped by

A. Forging B. Brazing C. Draw forming D. Welding Ill

20. Flame cutting is often used on

A. Iron and steel B. Thin sheet metal C. Aluminum D. Tin and lead

21. Screws which make their own threads in the workpiece are

A. Sheet metal screws B. Cap screws C. Machine screws D. All of the above

22. Hammering or pressing hot metal between dies at a high pressure is called

A. Drawing B. Forging C. Welding D. Heat treating

23. Which process changes the grain structure of metal?

A. Forging B. Heat treating C. Drawing D. All of the above

24. The main purpose of heat treating is

A. To change the shape of the material B. To change properties such as hardness and strength C. To make a metal alloy D. To improve the appearance of the material

25. Alloying is done to improve

A. Hardness B. Strength C. Ease of machining D. All of the above

26. In the injection molding process

A. The material is placed ona conveyor belt B. Sand is injected into the form of a mold C. Air pressure forces the material against the side of the mold D. The material is forced into a die or mold 273

27. Which process would not be used to produce a round hole on a metal lathe?

A. Turning B. Boring C. Reaming D. Drilling

28. The best process for producing long pieces of stock would be

A. Injection molding B. Extruding C. Blow molding D. Compression molding

29. A p la stic bag can be sealed by heating and pressing the seam. This process is most like

A. Gas welding B. Gluing C. Arc welding D. Spot welding

30. Forming a f la t piece of metal into pipe by pulling i t through a die is an example of

A. Forging B. Drawing C. Braking D. Extrudi ng

All ferrous metals contain

A. Tin B. Lead C. Iron D. Zinc

32. Which of the following can exert the most pressure?

A. Wood screws B. Sheet metal screws C. Machine bolts D. Machine screws

33. What process would most likely be used to make a pop bottle?

A. Injection molding B. Extrusion C. Compression molding D. Blow molding 274

34. 1 he heads of n ails and screws are formed by

A. Cold forging B. Drawing C. Hot forging D. Milling

35. Which of the following could be machined on a milling machine?

A. Wood B. Metal C. P lastic D. All of the above

36. Grinding is most lik e

A. Milling B. Sanding C. Turning D. Drilling

37. Which material can be machined on a lathe?

A. Wood B. Metal C. P lastic D. All of the above

38. The main purpose of this process is to change the grain structure of the metal

A. Forging B. Heat treating C. Drawing D. Milling

39. Thermosetting materials are most often formed by

A. Injection molding B. Compression molding C. Extrusion D. Blow molding

40. Which is an example of a drawn part?

A. A street sign B. An engine piston rod C. A good quality wrench D. A steel pipe 275

41. S traig h t lin e bending is done by

A. Brake bending B. Drawing C. Forging D. Blanking

42. The process which heats the metal to the lowest temperature is

A. Arc welding B. Gas welding C. Soldering D. Brazing

43. Which type of material can be softened and reshaped over and over again?

A. All thermosetting materials B. All thermoplastic materials C. All natural materials D. All synthetic materials

44. What process is used to make hollow plastic toys?

A. Injection molding B. Extrusion C. Compression molding D. Blow molding

45. The main ingredients of steel are

A. Copper and zinc B. Iron and carbon C. Tin and lead D. Aluminum and s ilv e r

46. If some parts of a product must be taken apart and put back together often, they should be held together by

A. An adhesive B. Nails C. Threaded fasteners D. Brazing

47. A threaded fastener which is usually used with a nut is

A. Machine bolt B. Sheet metal screw C. Cap screw D. All of the above 276

48. Toughness and fractu re resistan ce of hardened metal can be improved by

A. Annealing B. Quenching C. Tempering D. Forging

49. The most commonly used method of hot forming metal shapes is

A. Drawing B. Forging C. Brake bending D. Blanking

50. An operation on a lathe which produces a flat surface on the end of the workpiece is

A. Facing B. Reaming C. Turning D. Boring

51. Cutting out an irregular shape from sheet metal would probably be done on

A. A press brake B. A draw die C. A blanking die D. A forging die

52. D rilling can be done

A. On a d rill press B. On a lathe C. On a milling machine D. On all of the above

53. The internal cavity of a die would probably be made smooth by

A. Turning B. Grinding C. Blanking D. Braking

54. If several different kinds of materials have to be put together as one piece, the best process would be

A. Gluing B. Melding D. Brazing D. Soldering 277

55. Which of the following terms refers to getting the proper hardness?

A. Annealing B. Quenching C. Tempering D. Forging

56. The word synthetic means

A. Polymer B. Man-made C. Thermoplastic D. Thermosetting

57. Plastic parts for electric fry pans would be made of

A. Thermoplastic materials B. Thermosetting materials C. Either thermoplastics or thermosets D. Polymers

58. Spot welding melts metal using

A. An electric arc B. A gas flame C. Electric current D. None of the above APPENDIX H

TEST DATA

278 279

FREQUENCY DISTRIBUTION INITIAL TEST

ADVANCE ORGANIZER CONVENTIONAL OVERVIEW

Score Frequency Score Frequency

7 1 11 1 12 1 13 1 13 1 14 2 14 4 15 2 15 2 16 3 16 1 17 4 17 2 19 3 18 2 20 1 19 1 21 4 20 1 22 5 21 2 23 2 22 5 24 3 23 5 25 6 24 3 26 6 25 4 27 1 26 5 28 3 27 5 29 1 28 3 30 1 29 2 31 5 30 2 32 6 32 6 33 9 33 6 34 3 34 5 35 2 35 4 36 4 36 5 37 3 37 4 38 1 38 2 40 2 39 2 41 3 41 4 42 1 42 2 43 1 43 1 45 2 45 1 46 1 48 2 48 1 51 1 52 1 52 1 53 1 280

FREQUENCY DISTRIBUTION RETENTION TEST

ADVANCE ORGANIZER CONVENTIONAL OVERVIEW Score Frequency Score Frequency

7 1 10 2 9 1 11 6 10 1 12 2 11 1 13 4 12 3 14 3 13 6 15 3 14 1 16 4 15 5 18 2 16 2 19 4 17 2 20 3 18 4 21 3 19 8 22 3 20 3 23 2 21 2 24 5 22 2 25 1 23 3 26 1 24 1 27 4 25 3 28 4 27 3 29 5 28 3 32 4 30 4 33 2 31 3 34 2 32 4 35 3 33 2 36 5 34 3 37 2 35 2 38 2 36 6 39 3 37 42 2 38 43 2 39 44 1 42 45 1 43 53 1 44 56 1 45 47 51 52 53 281

TEST SCORES BY CLASS

TREATMENT ASSIGNED: ADVANCE ORGANIZER CLASS NO. 1

Student No. Initial Test ReteiTtton Test Combined Score

1 22 13 35

2 37 2b 62

3 22 18 40

4 51 52 103

5 30 39 69

6 52 53 105

7 17 35 52

8 36 13 49

9 14 15 29

10 43 47 90

11 48 16 64

12 39 37 76

13 36 32 68

14 42 27 69

15 41 36 77

16 26 7 33 282

TEST SCORES BY CLASS

TREATMENT ASSIGNED: ADVANCE ORGANIZER CLASS NO._2

Student No. Initial Test Retention Test Combined Score

1 35 39 74

2 23 20 43

3 35 23 58

4 38 39 77

5 45 44 89

6 12 13 25

7 30 24 54

8 22 19 41

9 34 42 76

10 3b 38 73

11 22 17 39

12 36 36 72

13 37 39 76

14 32 31 63

15 26 12 38

16 13 14 27

17 34 23 57 283

TEST SCORES BY CLASS

TREATMENT ASSIGNED: ADVANCE ORGANIZER CLASS NO. 3

Student No. Initial Test Retention Test Combined Score

1 18 15 33

2 15 11 26

3 33 36 69

4 41 13 54

5 33 32 65

6 28 34 62

7 39 36 75

8 32 27 59

9 32 39 71

10 34 30 64

11 35 30 65

12 32 34 66

13 34 36 70

14 25 30 55

15 14 20 34

16 37 31 68 284

TEST SCORES BY CLASS

TREATMENT ASSIGNED: ADVANCE ORGANIZER CLASS NO. 4

Student No. Initial-Test Retention Test Combined Score

1 53 51 104 2 32 39 71 3 32 36 68 4 17 20 37 5 33 28 61 6 27 19 46 7 38 31 69 8 28 33 61 9 28 28 56 10 16 17 33 11 42 45 87 12 21 30 51 13 25 23 48 14 15 12 27 15 33 33 66 16 41 43 84 17 41 44 85 18 26 21 47 19 23 34 57 20 24 19 43 285

TEST SCORES BY CLASS

TREATMENT ASSIGNED: ADVANCEi ■ .1, . ^ ORGANIZER ■ ...... —— CLASS NO. 5 —

Student No. Initial Test Retention Test Combined Score

1 27 15 42 2 29 32 61 15 19 10 29 4 24 16 40 5 29 22 51 6 14 15 29 7 24 12 36 8 27 19 46 9 23 18 41 10 23 18 41 11 26 18 44 12 25 19 44 13 36 35 71 14 23 9 32 15 22 13 35 16 34 25 59 17 36 21 57 18 37 22 59 19 33 28 61 20 21 19 40 21 18 15 33 286

TEST SCORES BY CLASS

CLASS NO. 6 TREATMENT ASSIGNED: ■ CONVENTIONAL » ^ . - M» - OVERVIEW — I ■ 1.1 M I-1 -

Student No. Initial Test Retention Test Combined Score

1 34 43 77 2 45 44 89 3 23 16 39 4 11 13 24 5 17 14 31 6 45 29 74 7 22 20 42 8 37 32 69 9 14 13 27 10 24 11 35 11 14 19 33 12 34 39 73 13 15 16 31 14 32 29 61 15 16 13 29 16 36 28 64 17 17 11 28 18 2b 18 43 19 24 11 35 287

TEST SCORES BY CLASS

TREATMENT ASSIGNED: CONVENTIONAL OVERVIEW CLASS NO. 7

Student No. Initial Test Retention Test Combined Score

1 31 24 55 2 26 2/ 53 3 25 37 62 4 34 33 67 5 32 35 67 6 46 42 88 7 43 45 88 8 22 21 43 9 40 28 68 10 21 15 36 11 38 37 75 12 33 42 75 13 36 22 58 14 26 25 51 15 13 10 23 16 25 29 54 17 25 19 44 18 31 26 57 19 52 53 105 288

TEST SCORES BT CLASS

TREATMENT ASSIGNED: CONVENTIONAL OVERVIEW CLASS NO. 8

Student No. Initial Test Retention Test Combined Score

1 15 11 26

2 25 21 46

3 19 14 33

4 26 10 36

5 19 16 35

6 32 14 46

7 16 11 27

8 31 15 46

9 33 24 57

10 20 12 32

11 28 12 40

12 33 24 57

13 41 36 77

14 30 29 59 289

TEST SCORES BY CLASS

TREATMENT ASSIGNED: CONVENTIONAL OVERVIEW CLASS NO. 9

Student No. Initial Test Retention Test Combined Score

1 27 24 51 2 35 39 74 3 23 23 46 4 33 23 56 5 42 36 78 6 37 36 73 7 41 36 77 8 16 19 35 9 29 27 56 10 21 19 40 11 33 32 65 12 17 18 35 13 21 15 36 14 21 21 42 15 28 22 50 16 28 28 56 17 33 35 68 18 24 24 48 19 31 29 60 20 36 38 74 290

TEST SCORES BY CLASS

TREATMENT ASSIGNED: CONVENTIONAL OVERVIEW CLASS NO. 10

Student No. Initial Test Retention Test Combined Seore

1 22 22 44

2 32 32 64

3 26 27 53

4 40 43 83

5 26 34 60

6 37 35 72

7 36 38 74

8 32 39 71

9 35 32 67

10 25 16 41

11 33 28 61

12 31 27 58

13 48 56 104

14 22 13 35

15 41 34 75

16 32 36 68 APPENDIX I

CORRESPONDENCE

291 292

UNI

UNIVERSITY OF NORTHERN IOWA . Cedar Falls, Iowa 50613

Department of Teaching Malcolm Price Laboratory School February 8, 1978

Mr. Paul Warrington American Technical Society 5608 Stony Island Avenue Chicago, IL 60637

Dear Mr. Warrington:

This letter is a followup to our telephone conversation of February 7. Its purpose is to ask for permission to reproduce illustrations from the following text:

WAGNER, MODERN INDUSTRY 170 Fig. 7-40 172 7-46 380 15-2 381 15-4 383 15-12 384 15-15 385 15-17 385 15-18 192 8-33 198 8-49 185 8-15 188 8-23

I would like to reproduce the illustrations in two written learning passages and two tests which are being developed for an experimental study of the effectiveness of two instructional methods. The study is being conducted as part of a dissertation problem at Ohio State University under the supervision of Dr. Willis E. Ray.

The illustrations themselves are not part of the experimental treat­ ment. They will be used in materials read by all groups in the study. The illustrations have been chosen on the basis of their clarity in explaining certain industrial production processes. 293

American Technical Society Page 2 February 8, 1978

The learning passages and tests will be administered to about 275 students over a four-day period. Quality reproductions will be made of the illustrations, and the materials will be printed by offset lithography. All use of materials will be done in class. No materials will be taken home by students. All printed materials will be returned to the instructor at the end of the reading period. The only use of the materials will be for this research problem and any subsequent research which might be conducted.

Copies of the materials will appear in the appendix of the disser­ tation which will subsequently be microfilmed by University Microfilms, Ann Arbor, Michigan. Persons requesting copies of the dissertation from University Microfilms will receive copies of the learning passages and tests along with the rest of the dissertation.

An acknowledgement of permission to reproduce each illustration will appear with each respective illustration.

I will be most happy to supply American Technical Society with a summary of the research data upon completion of the study.

I look forward to your reply.

Sincerely,

(s) Donald R. Darrow

Donald R. Darrow Assistant Professor of Teaching dk 294

ATS

AMERICAN TECHNICAL SOCIETY

February 15, 1978

Mr. Donald R. Darrow Malcolm Price Laboratory School University of Northern Iowa Cedar Falls, Iowa 50613

Dear Mr. Darrow:

We are happy to give you permission to reproduce the (12) illus­ trations from our text "Modern Industry" as outlined in your letter of 7th, February 1978.

Will appreciate getting credit on the illustrations and also a summary of your research upon completion.

We wish you success in your endeavors.

Sincerely,

(s) Paul S. Warrington

Paul S. Warrington

PWS:T

5608 Stony Island Avenue, Chicago, IL 60637 (312-643-8400 295

UNI

UNIVERSITY OF NOTHERN IOVTA . Cedar Falls, Iowa 50613

Department of Teaching Malcolm Price Laboratory School

February 17, 1978

Mr. Michael Kenny, Executive Editor Chas. A. Bennett Co., Inc. 809 Detweiller Drive, Dept. EE8 Peoria, IL 61614

Dear Mr. Kenny:

This le tte r is a followup to our telephone conversation of February 7. Its purpose is to ask for permission to reproduce illustrations from the following texts:

Kazanas, et a l., Johnson, Manufacturing Processes Technology of Industrial Materials

149 Fig. 30-10 P. 132 Fig. 3-24 151 31- 1 142 3-38 153 31- 9(B) 144 3-41 169 36- 3 144 3-40 169 36- 5 146 3-44 170 36- 7 168 35- 3 188 45- 1 182 4-19 198 47- 6 198 47- 8 200 48- 1 335 67- 6 393 76- 3 535 107- 1 560 112-10 561 112—12(A) 562 112-13 352 71- 4(A)

I would like to reproduce the illustrations in two written learning passages and two tests which are being developed for an experimental study of the effectiveness of two instructional methods. The study is being conducted as part of a dissertation problem at Ohio State University under the supervision of Dr. Willis E. Ray. 296

Chas. A. Bennett Co., Inc. Page 2 February 17, 1978

The illustrations themselves are not part of the experimental treatment. They will be used in materials read by all groups in the study. The illustrations have been chosen on the basis of their clarity in explaining certain industrial production processes.

The learning passages and tests will be administered to about 275 students over a four-day period. Quality reproductions will be made of the illustrations, and the materials will be printed by offset lithography. All use of materials will be done in class. No mater­ ials will be taken home by students. All printed materials will be returned to the instructor at the end of the reading period. The only use of the materials will be for this research problem and any subsequent research which might be conducted.

Copies of the materials will appear in the appendix of the disser­ tation which will subsequently be microfilmed by University Microfilms, Ann Arbor, Michigan. Persons requesting copies of the dissertation from University Microfilms will receive copies of the learning passages and tests along with the rest of the dissertation.

An acknowledgement of permission to reproduce each illustration will appear with each respective illustration.

I will be most happy to supply Chas. A. Bennett Co., Inc. with a summary of the research data upon completion of the study.

I look forward to your reply.

Sincerely yours,

(s) Donald R. Darrow

Donald R. Darrow Assistant Professor of Teaching dk 297

B

Chas. A. Bennett Co., Inc. 809 West Detweiller Drive, Peoria, Illinois (309) 691-4454

February 22, 1978

Mr. Donald R. Darrow Assistant Professor of Teaching University of Northern Iowa Cedar Falls, Iowa 50613

Dear Mr. Darrow:

We grant permission for you to use the illustrations listed in your le tte r of February 17, provided that their use is specifically as described in that le tter.

You state that an acknowledgement of permission will be used with each illustration. With the illustrations taken from MANUFACTURING PROCESSES, please use this statement: From MANUFACTURING PROCESSES, copyright 1973, by Johnson. Reproduced with permission.

For those taken from the other book, please use this state­ ment: From TECHNOLOGY OF INDUSTRIAL MATERIALS, copyright 1974, by Kazanas, et al. Reproduced with permission.

We wish you well with your dissertation and would be pleased to see a summary of y o u r findings.

Sincerely,

(s) Michael Kenny

Michael Kenny, Executive Editor

MK:mn

Bennett Books . Educational Publishers Since 1899 298

UNI

UNIVERSITY OF NORTHERN IOWA . Cedar Falls, Iowa 50613

Department of Teaching Malcolm Price Laboratory School

February 17, 1978

Mr. George Fisher Goodheart-Willcox 123 W. Taft Drive South Holland, IL 60473

Dear Mr. Fisher:

This letter is a followup to ourtelephone conversation ofFebruary 7. Its purpose is to ask for permission toreproduce illustrations from the following texts:

Baird, Oxyacetylene Welding

P. 40 Figure 14-1 38 11-6

Walker, Modern Metalworking

P. 18- 1 Fig. 18-1 18-1 18-3 18-2 18-4 18-3 18-8 1-16 1-12 23- 4 23-5

Walker, Arc Welding

P. 29 Figure 8-1

I would like to reproduce the illustrations in two written learning passages and two tests which are being developed for an experimental study of the effectiveness of two instructional methods. The study is being conducted as part of a dissertation problem at Ohio State University under the supervision of Dr. Willis E. Ray. 299

Goodheart-Wi.l 1 cox Page 2 February 17, 1978

The illustrations themselves are not part of the experimental tre a t­ ment. They will be used in materials read by all groups in the study. The illustrations have been chosen on the basis of their clarity in explaining certain industrial production processes.

The learning passages and tests will be administered to about 275 students over a four-day period. Quality reproductions will be made of the illustrations, and the materials will be printed by offset lithography. All use of materials will be done in class. No materials will be taken home by students. All printed materials will be returned to the instructor at the end of the reading period. The only use of the materials will be for this research problem and any subsequent research which might be conducted.

Copies of the materials will appear in the appendix of the disser­ tation which will subsequently be microfilmed by University Microfilms, Ann Arbor, Michigan. Persons requesting copies of the dissertation from University Microfilms will receive copies of the learning passages and tests along with the rest of the dissertation.

An acknowledgement of permission to reproduce each illustration will appear with each respective illustration.

I will be most happy to supply Goodheart-Willcox with a summary of the research data upon completion of the study.

I look forward to your reply.

Sincerely yours,

(s) Donald R. Darrow

Donald R. Darrow Assistant Professor of Teaching dk 300

GOODHEART-WILLCOX G-W Useful Books 123 W. Taft Drive . South Holland, 111. 6Q473 Phone 312-333-7200

February 21, 1978

Mr. Donald R. Darrow Dept, of Teaching Malcolm Price Laboratory School University of Northern Iowa Cedar Falls, Iowa 50613

Thank you, Mr. Darrow,

for your le tte r of February 17 relative to reproducing material from our books 0XACETYLENE WELDING and MODERN METALWORKING.

You have our permission to reproduce the material under the condit­ ions as outlined in your letter.

We will appreciate receiving a summary of the research data when your study has been completed.

We wish you the best of luck with this project.

Sincerely,

George A. Fisher (s)

George A. Fisher President

GAFrch 3Q1

UNI

UNIVERSITY OF NORTHERN IOWA . Cedar Falls, Iowa 50613

Department of Teaching Malcolm Price Laboratory School

February 17, 1978

Mr. Ron Dale McKnight Publishing Co. 808 Eldorado Road Bloomington, IL 61701

Dear Mr. Dale:

This le tte r is a followup to our telephone conversation with your secretary on February 7. Its purpose is to ask for permission to reproduce illustrations from the following text:

Ludwig, McCarthy, Metalwork-Technology McCarthy & Smith, and Repp, and Practice Machine Tool Technology

P. 25 Fig. 1- 4 P. 149 Fig. 18- 8 26 1- 7 149 18-10 27 1- 9 295 33- 1 27 1- 11 296 33- 3 209 8- 74 296 33- 4 266 9-131 296 33- 5 270 9-147 296 33- 6 275 9-161 490 54- 1 411 12- 6 517 55-38 522 55-50 589 57-47 592 57-50 604 58-13 212 26- 2

I would like to reproduce the illustrations in two written learning passages and two tests which are being developed for an experimental study of the effectiveness of two instructional methods. The study is being conducted as part of a dissertation problem at Ohio State University under the supervision of Dr. Willis E. Ray 302

McKnight Publishing Co. Page 2 February 17, 1978

The illustrations themselves are not part of the experimental tre a t­ ment. They will he used in materials read by all groups in the study. The illustrations have been chosen on the basis of their clarity in explaining certain industrial production processes.

The learning passages and tests will be administered to about 275 students over a four-day period. Quality reproductions will be made of the illustrations, and the materials will be printed by offset lithography. All use of materials will be done in class. No materials will be taken home by students. All printed materials will be returned to the instructor at the end of the reading period. The only use of the materials will be for this research problem and any subsequent research which might be conducted.

Copies of the materials will appear in the appendix of the disser­ tation which will subsequently be microfilmed by University Microfilms, Ann Arbor, Michigan. Persons requesting copies of the dissertation from University Microfilms will receive copies of the learning passages and tests along with the rest of the dissertation.

An acknowledgement of permission to reproduce each illustration will appear with each respective illustration.

I will be most happy to supply McKnight Publishing Co. with a summary of the research data upon completion of the study.

I will look forward to your reply.

Sincerely,

(s) Donald R. Darrow

Donald R. Darrow Assistant Professor of Teaching dk 303

MCKNIGHT PUBLISHING COMPANY/BLOOMINGTON, ILLINOIS 61701/309-663-1341

February 28, 1978

Mr. Donald R. Darrow Department of Teaching Malcolm Price Laboratory School University of Northern Iowa Cedar Falls, Iowa 50613

Dear Don:

This is in response to your February 17 letter. I truly appreciate the effort you put forth in identifying how you intend to use the illustrations from Machine Tool Technology and Metalwork Technology and Practice" You have identified a strategy that protects our copyright and the best interests of the author and producers. Based on the restrictions outlined in your February 17 le tte r, we are happy to grant you permission to reproduce the illustrations identified in your correspond­ ence. Please credit Machine Tool Technology by McCarthy and Smith and Metalwork Technology and Practice by Ludwig, McCarthy, and Repp.

I would appreciate very much receiving a summary report of your research. Best wishes to you in your professional development.

Sincerely yours,

Ron Dale (s)

Ron Dale Vice President, Editorial

RD/bjm BIBLIOGRAPHY

304 BIBLIOGRAPHY

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