Can an Insulator Be Electrifi ed? Teaching Electricity in Elementary and Middle School in the Age of NGSS

Varda Bar Hebrew University of Jerusalem, Jerusalem, Israel Aviv Spector Shirtz Hebrew University of Jerusalem, Jerusalem, Israel Yafa Brosh Hebrew University of Jerusalem, Jerusalem, Israel Cary Sneider Portland State University, Portland, Oregon

Abstract In light of extensive research demonstrating widespread misconceptions about electricity, this paper describes a learning study that targeted the most likely source of diffi culty—failure of middle school pupils to develop a mental model that serves as a bridge between static and current electricity. During the intervention, pupils fi rst envision static electricity as due to mechanical forces that separate two kinds of electrical charges. They then expand the model to account for current electricity, noting that the battery uses chemical means to separate charges, thus providing a force to drive an electric current. Pupils also develop a nuanced understanding of the role played by insulators and conductors in static and current electricity. The instructional unit combines hands-on activities and demonstrations in which pupils’ pre-instructional ideas confl ict with their observations, discussions to help them resolve the confl icts, and direct instruction about the history of electrical science*. The underlying philosophy is constructivist—to help pupils develop a meaningful and fl exible mental model of electrical phenomena.

Introduction of paper. In the fourth grade they are at the middle school level, when pupils In a 3-minute video that has been expected to learn about electric circuits are expected to develop a mental model viewed more than half a million times on as a means for converting energy from that explains both static and circuit elec- YouTube graduates of Harvard and MIT, one form to another and transferring it tricity. However, no researchers have including students majoring in STEM from place to place. By middle school, yet developed an instructional method fi elds, express confi dence that they can pupils are expected to bring those core that helps pupils develop such a model. light a bulb with a battery and one wire, ideas together, and explain the phenom- To meet this need we have developed a but most were unable to do so (Schneps ena of both static and circuit electricity sequence of seven short lessons designed and Sadler, 1997a). While it is shocking by applying the atomic model of matter. to help middle school pupils construct that so many top students have such a These core ideas are foundational to later a conceptual bridge between static and poor understanding of electricity, it is not understanding of electric and magnetic circuit electricity that could serve as a surprising in light of the many miscon- fi elds, similar to gravitational fi elds, allow- springboard to a fi eld-based model of elec- ceptions that exist about electricity, com- ing action-at-a-distance, and eventual tromagnetism. The quasi-experimental mon to pupils in many countries, that we understanding of electromagnetic radia- learning study consists of two parts, both describe below, under Prior Research. tion at the high school level. conducted in Israel. Part one is a survey According to the Next Generation As pointed out by several researchers of 100 high achieving middle school pupils Science Standards (NGSS Lead States, (e.g. Eylon & Ganiel, 1990; Galili & who did not receive the experimental 2013), third grade pupils are expected to Goihbarg, 2005; Shen & Linn, 2010) an treatment; although they had received tra- learn about static electricity with activi- important source of persistent miscon- ditional classes in electricity that are part ties such as charging a piece of glass ceptions about electrical phenomena may of the national curriculum. Part two is a or plastic, and using it to pick up bits be a weak link in the learning progression study of 31 eighth grade average pupils,

Keywords: Concept Formation, Elementary Science, Middle School Science, Experiential Learning, Learning Progression, Electricity, Properties of Matter.

* There are many historical accounts on the history of the science of electricity. Sources that we consulted for the historical references in this paper include Azimov (1966), Cardwell (1995), Derry and Williams (1961), Park (1989), Wolf (1961), DuFay (1734), and Faraday (1833).

24 SCIENCE EDUCATOR who received pre-tests, the experimental electricity, which is in contrast to experts’ understanding of static electricity to their treatment, and post-tests. As we document views of electricity as a fi eld-like phenom- understanding of electric circuits. in this paper, on the post-test the average enon, as emphasized in the NGSS at the Using a historical approach, Schiffer & pupils who received the experimental treat- middle and high school levels. Guerra (2015) complemented the standard ment out-performed the high achieving During the next decade studies contin- physics curriculum in Brazil by providing pupils who did not receive the treatment. ued to focus on circuit electricity. Lee’s 9th grade pupils with a two-page historical (2007) study of 3,608 sixth grade pupils narrative to help them understand key elec- Previous research in Taiwan about their understanding of tricity concepts and the nature of science. Borges & Gilbert (1999) summarized batteries, revealed similar misconcep- Electricity and Vital Force: the Galvani more than twenty studies of pupils’ mis- tions about electric circuits, as well as and Volta Controversy was a two-page nar- conceptions about electricity, noting that ideas about what’s inside a battery, and rative designed to engage the pupils in dis- the great majority focused on simple elec- the function of series and parallel circuits. cussions leading to a complex view of how tric circuits involving batteries and bulbs. Mehalic et al. (2008) conducted a learning science actually progresses and a deeper Kärrqvist (1985), for example, identi- study to compare two methods of instruc- understanding of electrical concepts than fi ed six different mental models of circuits tion on electric circuits. Ten teachers and was possible with the standard textbook among secondary pupils, such as the uni- 587 pupils used an engineering design alone. Leone (2014) also took a historical polar model, in which electricity goes from approach to plan and construct alarm sys- approach, starting with an in-depth review the battery to the bulb where it’s “used up” tems, compared with fi ve teachers and of the conceptual diffi culties that scientists and the two-component, or “clashing cur- 466 pupils who used a scripted inquiry encountered when developing the science rent” model in which streams of plus and approach to teach the same concepts. The of electrical phenomena in the seventeenth minus electricity fl ow from the two ends of design group showed a 16% gain on a and eighteenth centuries, and comparing the battery to the bulb where they meet and test of circuit concepts, which was twice those struggles with the diffi culties that light the bulb. Borges and Gilbert contrib- as great as the 7% gain by students who fi fth grade pupils encountered when learn- uted to this tradition by analyzing mental experienced the scripted inquiry method. ing about electric circuits. Rather than a models of circuit electricity for a wider Subsequently, studies on static elec- learning study, however, Lee’s approach range of ages for both pupils and adults. tricity have been carried out. A learning was to further elucidate these common Also during this early period, Cohen et al. study by Shen and Linn (2011) tested an conceptual diffi culties in order to inspire (1983) found that pupils’ understanding of electrostatics unit to help high school new instructional approaches. electrostatics was at a lower level than their pupils integrate scientifi c explanations Park et al. (2001) is of special signifi - understanding of current electricity, includ- with everyday phenomena. The unit pre- cance to the current study since it con- ing at the high school level, and Neidderer sented videos and hands-on activities of cerns ninth grade pupils’ and second and Goldberg (1993) found that college static electricity, elicited pupils’ initial year college students’ understanding of students commonly held a “source—sink” explanations, presented visualizations the role of insulators, conductors, elec- model, meaning that electrical current trav- and simulations connecting observable trifi cation, and the purpose and func- eled from the source (battery) to a sink phenomena and atomic-level processes, tion of electroscopes. The subjects were (bulb), possibly because the battery is typi- and opportunities to refl ect on these expe- asked to predict whether or not an elec- cally described as a “source” of electrical riences during discussions. Although one troscope could be charged when a con- current. Shipstone (1984) found that the of the activities involved the role of insu- necting copper or wooden rod is touched majority of pupils age 12-18, and even lators and conductors in an electric cir- by a charged object. Although both kinds several graduates intending to become cuit, the investigators noted that helping of rods would in fact charge the electro- physics teachers, held what he termed the pupils connect electrostatics and electric scope the great majority of both groups “sequence model,” in which current is circuits would need additional instruc- predicted that just the copper rod would changed as it fl ows around the circuit and tional time. Mayer (2017) studied ninth charge the electroscope. Despite discon- encounters each component in sequence. grade pupils’ changing mental models fi rming evidence most pupils clung to Shipstone confi rmed Cohen’s fi nding that during a ninth-grade unit on electric their core mental models, proposing “pro- “current is the primary concept used by stu- fi elds and atomic structure that involved tective hypotheses” consistent with Imre dents while potential difference is regarded three-dimensional learning as called for Lakatos’ theory of conceptual change in as a consequence of current fl ow and not in the Next Generation Science Stan- science. It is important to note that the its cause (Shipstone, 1984, pp. 194-195). dards. The pupils struggled to change participants did not have an opportunity Stocklmayer and Treagust (1994, 1996), their atomic models in light of evidence, to resolve confl icts through discussion in suggested that a source of widespread mis- but ended up with dynamic models of that study. Similarly, Heller and Finley conceptions about electricity may be due atomic structure that they could apply (1992), found that elementary and middle to the model of electricity as fl uid fl ow to explain phenomena after an entire school teachers also clung to a few core common to textbooks and most teachers’ semester. These studies demonstrate that ideas (such as the circuit is initially empty beliefs in a particulate model of the fl ow of it is not easy for pupils to connect their of the “stuff” that fl ows through the

SPRING 2019 VOL. 27, NO. 1 25 conductors, and the battery is the source received a pre-test followed by the experi- Part 1 Survey of 100 High of the current) and developed “protective mental treatment, and then a post-test. Achieving Pupils hypotheses,” so they would not need to Our choice of schools for the two stud- We administered a survey to 100 mid- change their core ideas, even in light of ies was strategic. As in many developed dle school pupils in grades seven, eight disconfi rming evidence. countries, there are differences among the and nine, (mean ages 12, 13 and 14 years The instructional sequence that will be populations of different schools. For the old) from two schools of high achiev- tested in this study has evolved through fi rst study we chose two middle schools ing pupils. The survey consisted of four a line of research extending over two with high achieving pupils as measured open-ended questions: decades (Bar & Zinn, 1998; Azaiza et al., on standardized tests. Their responses to Can an insulator be electrifi ed? 2006; Azaiza et al., 2012; Bar et al., 2016). our electricity questionnaire represent the Can a conductor be electrifi ed? The most recent of these was a learning highest level of understanding that can rea- Defi ne an insulator. study for fourth graders on conductors sonably be expected of pupils who have Defi ne a conductor. and insulators in circuit electricity. Prior engaged in the Israeli national science cur- to instruction most fourth graders stated riculum, which includes the study of elec- The survey was delivered by the pupils’ that insulators do not conduct electricity, trostatics at the elementary level and circuit teachers and completed in about 20 min- and that the role of the insulators is to pre- electricity at the middle school level, and utes. The results are summarized in Table 1. vent people from getting an electric shock. is similar to the curriculum of most devel- Consistent with the reports by Guisasola The treatment was a two-hour addition oped nations, including the United States. et al. (2008) and Park (2001), the great to the Israeli national curriculum unit on For the learning study we selected a mid- majority of pupils (86%) claimed that an electricity in which pupils used a mag- dle school with primarily average pupils as insulator cannot be electrifi ed despite the nifi er to examine a light bulb, noting the measured by the same standardized tests, fact that all of the pupils had electrifi ed arrangement of conductors and insulators but who had not yet taken the 8th grade pieces of glass or plastic, when they stud- that enabled electricity to fl ow through unit on electricity. Our purpose in select- ied static electricity in elementary school. the fi lament. On the post-test, most pupils ing these schools was to determine if the When asked about the role of insulators in recognized that insulators also played an instructional sequence we had devised electrical circuits, 75% of the pupils said it important role in circuits by separating would enable average achieving pupils to was to protect the user, and only 27% men- conducting components in order to chan- do as well (or better) on a content question- tioned a functional role beyond that. A few nel the electricity to where it is needed, naire than high achieving pupils who had pupils gave more than one answer. The jus- indicating that they understood how the experienced Israel’s national curriculum. tifi cations for some of the pupils’ answers bulb functions and had developed a more nuanced understanding of the role of Table 1. Part 1 Survey Results insulators in electric circuits. The lesson, which was successful for fourth-graders, 7th (N =22) 8th (N = 11) 9th (N=67) Total (N=100) was similar to a lesson for high school Q1. Can an insulator be electrifi ed? %# % # % #% # pupils documented in a 55-minute video Yes 9% 2 18% 2 15% 10 14% 14 (Schneps and Sadler, 1979b) that expands No 91% 20 82% 9 85% 57 86% 86 on the YouTube clip showing graduates Q2. What is the role of the insulator of Harvard and MIT who cannot light a in an electric circuit? bulb with a battery and single wire. The To protect the user 91% 20 45% 5 75% 50 75% 75 study reported in this paper extends this Functional role 27% 6 36% 4 25% 17 27% 27 line of research to the middle school level, No answer 0 0 36% 4 9% 6 10% 10 with the goal of developing an instruc- Q3. What is a conductor? tional sequence that will counter pupils’ Something that transfers electricity 86% 19 91% 10 85% 57 86% 86 over-simplifi ed views of insulator and Something that can be electrifi ed 5% 1 0% 0 7% 5 6% 6 conductor, and help them develop a more nuanced, meaningful, and useful under- Something that transfers energy 0% 0 0% 0 7% 5 5% 5 standing of these important concepts. No answer 14% 3 9% 1 1% 1 5% 5 Q4. What is an insulator? Something blocks the transfer Methodology & Results 82% 18 64% 7 78% 52 77% 77 The quasi-experimental research con- of electricity sisted of two parts. Part one is a survey of Something that cannot be electrifi ed 5% 1 0% 0 9% 6 7% 7 Something that does not transfer 100 middle school pupils who had previ- 0% 0 0% 0 9% 6 6% 6 ously learned about electricity but did not energy receive the experimental treatment. Part Something that insulates current 0% 0 18% 2 3% 2 4% 4 two is a learning study in which pupils No answer 5% 1 0% 0 4% 3 4% 4

26 SCIENCE EDUCATOR are listed below, starting with the most at another school, judged to include a for this effect is that the action of rub- common. (The number of pupils who gave majority of pupils at an average achieving bing the ruler (or the comb) took part of each justifi cation is cited in parentheses): level. Although the pupils had explored the electricity from it: “The comb seeks No, an insulator cannot be electrifi ed . . . these phenomena in elementary school, this electricity from the paper by attract- their more recent instruction in electric- ing it.” Some pupils said: “an insulator • “Since it does not conduct the current ity was limited to circuit electricity. The can be electrifi ed by static electricity,” it cannot be electrifi ed.” (70) study took place at the beginning of the and “when rubbed, some electric par- • “It cannot accept high values of year, before the pupils took the traditional ticles left the ruler or the comb seek- electrifi cation.” (11) eighth grade electricity unit. Instruc- ing for these missing particles, and the • “No, an insulator does not conduct tion was presented in two classes by two paper pieces were attracted.” Some of electric current; it cannot be electri- experienced science teachers. One of the the pupils mentioned a separation of dif- fi ed and affect an electric shock.” (6) teachers taught the class while the other ferent kinds of electricity: “rubbing took • “An insulator does not have recorded it. The two teachers changed part of electricity.” electric charge in it. It cannot their roles in the second class. Pupils At the teacher’s urging the pupils be electrifi ed.” (5) received pre-tests and post-tests with the shared recollections of other electrostatic Notice that justifi cations seem to be same four questions as in Part 1. Quali- phenomena, such as getting a tiny shock related to the fact that an insulator does tative fi ndings were based on recorded when touching something or someone, or not deliver an electric shock, as explicitly observations of the instructional pro- having their hair stand up. At this point stated in the third bullet. Nineteen pupils cess and class discussions, during which the teacher defi ned the phenomenon as did not justify their answers, and some pupils struggled to modify their thinking. electrifi cation, and the pupils elaborated pupils gave more than one justifi ca- The experimental treatment con- that when the comb is electrifi ed by tion. Following are justifi cations by the sisted of the following seven lessons rubbing, it exerts a force on the bits of minority of pupils who said that an insu- aimed at helping pupils build a mental paper or sawdust due to the loss of part lator can be electrifi ed. As above, some bridge between their understanding of of the electricity. In addition, the teacher pupils gave more than one answer. static electricity and circuit electricity. added the explanations for the effect of Yes, an insulator can be electrifi ed. . . Lesson 1 Electrify an Insulator using the rubbing as taking some electricity a comb. In constructivist tradition, we from the comb as the source of the sug- • “The material does not conduct elicited the pupils’ initial ideas by asking gested force. (This is the same explana- the current, so electricity stays in them to share their answers to the fi rst tion for electrifying bits of amber given by the same place, and electrifi ed the question on the pre-test in a class discus- Thales of Miletus in what is now Greece, matter a little bit.” (15) sion. The great majority of students, as more than 2,500 years ago.) • “If the electric force is strong enough, judged by the teacher, said that an insu- The fi rst lesson resulted in pupils’ agree- it can electrify an insulator.” (7) lator cannot be electrifi ed. Most of the ment that the insulator was electrifi ed since • “The material does not conduct pupils justifi ed their view by saying that it could attract bits of paper and sawdust, the electricity, and the electricity the insulator does not conduct electricity. and that electrifi cation may have been stays with him and it does not Some pupils mentioned the protective caused by removing some of the electricity. create an electric shock.” (6) function of the insulator: “if we touch Lesson 2 First attempt to electrify a • “It can be electrifi ed but it does the insulator we do not get electrifi ed.” conductor. The teacher asked the pupils not conduct the current.” (5) the pupil’s responses were quite similar if they thought they could electrify a • “Electricity affects the materials to those found in the survey. The protec- penny using the same method. Some said differently.” (4) tive function of the insulator and the view yes and others said no. When they tried These minority views anticipate some that it cannot be electrifi ed prevailed it, the pupils found they could not elec- of the pupils’ observations who experi- among pupils of varying achievements, trify the penny by rubbing. The penny enced the instruction that took place in as well as in all ages on the survey. did not attract the small pieces of paper. the second part of the research. Some The pupils were then given a piece of The pupils discussed their ideas about of these pupils may be recalling recent wool cloth and a plastic comb or ruler, why the comb could be electrifi ed, but experiences in which they received an so they could rub the plastic and use it the penny could not. electrostatic shock by touching an elec- to pick up bits of paper or sawdust, as The pupils next built a circuit to test the trically isolated object, such as a sweater they did in elementary school. The results conductivity of various materials, includ- or car, in extremely dry weather. confl icted with their previous views. ing the comb and penny and used their When asked to explain what they thought circuit to classify materials as con ductors Part 2 Learning study with 31 happened the pupils stated that rubbing or insulators. A penny was included among average pupils the plastic object created a force that the conductors and the comb was not. We undertook a learning study with 31 attracted light objects. Some stated that it Experience with the classifi cation eighth grade pupils (mean age 13 years) was electrifi ed. A few said that the reason scheme showed that in contrast to their

SPRING 2019 VOL. 27, NO. 1 27 prior views, insulators are the ones that At the end of Lesson 3 the pupils were head of the electroscope the same kind were electrifi ed by rubbing and not able to distinguish between insulators of extra charge went onto the metal rod conductors. The pupils concluded that and conductors and to provide their own and the gold leaf. Since both had the there was a problem. The discomfort explanations for why they felt that the same charge (in the pupils’ phrasing that pupils experience at this point is an force of electrifi cation only worked by rub- “they have the same electricity”) they essential step in modifying their current bing the insulators—not the conductors. repelled each other. The teacher added mental models, before they are able to Notice that the fi rst three lessons start to clarify: “Similar electric charges repel construct a different and more fruitful by having the pupils predict whether or each other, while different charges attract model in which the new information will not insulators can be electrifi ed, then pro- each other.” Several pupils remarked on make sense. viding experiences that contradict their the similarity of that observation with The conclusion that pupils take away expectations. The teacher then guides magnets, in which like poles repel, while from Lesson two is that the insulators are the pupils to resolve the problem in two opposite poles attract. With prompting the electrifi ed by simple rubbing but not the stages: fi rst by supporting the idea that pupils were able to add that the metal rod conductors. there are two kinds of electrical charge. and gold leaf must have had the same kind Lesson 3 Develop explanations. The At the elementary level pupils can learn of charge, so they repelled each other. teacher asked the pupils to explain how that in ordinary matter the charges are Thanks to their observations in Lesson they thought an insulator could be elec- equalized. Rubbing removes some of one 4, the pupils now realized that both con- trifi ed. They were urged to use their kind of charge leaving an excess of the ductors and insulators can be electrifi ed. knowledge about the structure of the other kind of charge. In middle school However, conductors can only be elec- atom consisting of positive and negative pupils can connect the phenomenon with trifi ed if they are isolated so the charges charges to explain their observations. a mental model of atomic structure, as “cannot run away.” This experience also Some of them explained that “from the we describe in Lesson 4. helped the pupils envision like charges two kinds of electricity a bit of one kind Lesson 4 A further attempt to elec- spreading over the surfaces of two con- was taken from the comb, making the trify a conductor. At this stage the pupils ductors (in the electroscope), so they comb electrifi ed.” The teacher added that are able to explain how an insulator is repel each other. the two kinds of electric charges were electrifi ed, but most of them were now Lesson 5 Extend the electric effect. separated when rubbing plastic with convinced that the conductor cannot be Bar & Zinn (1998) and Leone (2014) wool, with some remaining on the comb electrifi ed. So when the teacher asked, have pointed out that the history of sci- and some rubbing off on the wool. “Do you think we could electrify a con- ence can often provide useful insights Given this new information, the pupils ductor?” the pupils responded that it can- for researchers by suggesting the pos- concluded that the comb became elec- not be done because the charge spreads sible causes of learner’s diffi culties, as trifi ed when it had more of one kind of out and gets weaker. The confl ict is now well as for teachers to identify these dif- electrical charge concentrated in one reversed—the pupils now think that the fi culties. Children can also benefi t from place. For the penny, however, the pupils conductor cannot be electrifi ed. accounts of scientists of the distant past concluded that, “the electricity must After this discussion, the teacher who may have shared some of their own have spread out, so the force became showed the pupils an electroscope with ideas about the world, and how the scien- very weak and could not affect the little a gold leaf attached to a metal rod. The tists eventually changed their ideas as a objects.” pupils touched the electrifi ed comb to the result of new data, or new ways of think- head of the electroscope and observed ing. Such is the case with pivotal discov- Teacher: Are the electrical charges that the gold leaf spread away from the eries by Stephen Gray (1666-1736) and created by rubbing with wool? metal rod. The teacher explained what Charles Francois DuFay (1698-1739). Pupil: The rubbing separates occurred as follows: “We can electrify a This lesson on the history of science was charges, so there are more conductor as long as it is isolated from timed to coincide with a period in which charges of one kind together other conductors.” The pupils added that the pupil’s thinking is more fl uid, having in one place. when we tried to electrify the coin, the recently been surprised to fi nd that an Pupil: Charges are not created, they charge ran away into our hand, so it did insulator can be electrifi ed, and a con- are separated. not keep the charge. The gold leaf in the ductor can be electrifi ed in some cases Pupil: In the insulator the charge electroscope is isolated, “so the charge but not in other cases. does not spread out and we cannot run away.” Using a PowerPoint presentation, the feel the force. In the conductor The teacher then focused on the pupils’ teacher explained that in 1731 Stephen the force is not felt. observations that the gold leaf was Gray performed an important experi- The pupils summed up their ideas repelled from the metal rod, and asked ment. He electrifi ed an insulator and by drawing and writing about their them why they thought that happened. attached a silk thread to it. He found that attempts to electrify the comb and the With some coaching, the pupils realized the thread also had the electrical property penny. that when they attached the comb to the of attracting bits of paper. He did this a

28 SCIENCE EDUCATOR number of times and found that he could the conductors are isolated. The pupils battery*! The pupils noted that batteries get the electrical effect to extend up to demonstrated their understanding by produce an electrical force, similar to and 800 feet from the insulator! But when he expressing their appreciation of DuFay’s even stronger than an electrifi ed insulator supported the thread by a copper wire, important contributions to the science of created by rubbing. The teacher helped the electrical effect went away entirely. electricity. the pupils strengthen their mental bridge But Gray didn’t know about conductors Lesson 6 Insulators can also conduct between static and circuit electricity by yet, and the electroscope was not yet electricity. The aim of lesson six was explaining that a chemical process in the invented. He only knew that materials to demonstrate that insulators can con- battery separates positive and negative could be classifi ed as those that can be duct electricity if the distance across the charges in the solution to create a force electrifi ed (such as silk and glass) and insulator is very small, or if the electri- that causes current to run through a wire. those that cannot be electrifi ed (such as cal force is very large. This is a further The battery is not a source of charge or copper). Therefore, he concluded that extension of the symmetry between the current—just a means to use the sepa- when he connected the copper wire—a two kinds of materials. In this case the rated charges in the solution and the material that cannot be electrifi ed—it insulator was air. The pupils connected a electrodes to create an electrical force so killed the electrical effect in the silk wire to one side of a battery and brought that when the terminals are connected by thread. the other end close to the other battery a wire the charges will fl ow through the The teacher stopped the presentation at terminal and observed a spark. The spark wire due to the existing force. this point and asked, “Do you know why showed that electrical charges crossed The pupils ended the series of les- Gray was not able to electrify copper?” the tiny gap between the terminal and the sons by making batteries from lemons, The pupils were easily able to explain wire. This demonstrates what happens potatoes, or other materials, and using that copper is a conductor, so the charges in a lightning storm—where the electri- a commercial battery to trace the circuit must have “run away” through the copper cal force is strong enough for the spark through a light bulb, noting the comple- supports. He did not know that in order to extend many miles through the air. mentary roles played by the insulator and to electrify copper it had to be isolated. This experience is not dangerous since conductor in the construction of the light Continuing the PowerPoint presenta- the voltage of the battery is very low. bulb. tion, the teacher explained the work of The PowerPoint presentation continued Finally, the pupils summarized what Charles DuFay, who was the fi rst to real- to describe Benjamin Franklin’s experi- they learned about insulators and con- ize that there was another way to inter- ment with lightning: electricity can be ductors, including conditions under which pret Gray’s experiment. He invented a conducted through air since the electric insulators and conductors can and cannot new classifi cation system, which we now power is very strong. be electrifi ed or conduct electricity and call conductors and insulators. Accord- The pupils observed that there is a the role of insulating materials within ing to DuFay, materials like glass, rub- symmetry between the insulators and the an electric circuit. They also discussed ber, and (today) plastic can be electrifi ed conductors since they could now see that Gray’s experiment to extend the electri- but cannot conduct electricity. Remind- both can be electrifi ed and also conduct cal effect along a silk thread as a fi rst ing the pupils about their experiences electricity. step from static electricity to circuit elec- trying to electrify a coin, and then using Lesson 7 Circuit electricity (fi nal tricity, which is so important for today’s the electroscope, the teacher and the lesson). The unit concluded with a fi nal civilization. pupils concluded that materials like cop- PowerPoint presentation and activity to Finally, the teacher reminded the pupils per cannot be electrifi ed unless they are help the pupils connect their new under- how initial discoveries were later re- isolated, but they can conduct electricity. standing of static electricity with circuit interpreted by other scientists, as when DuFay was also the person who identi- electricity using a battery and bulb. The Gray’s experiment led DuFay to propose fi ed two different kinds of electricity that pupils learned about the initial discovery the idea that materials could be classi- we now call positive and negative. The by Luigi Galvani (1737-1798), showing fi ed as conductors and insulators, and the pupils accepted DuFay’s ideas since they that frogs’ legs jump when touched by two case in which Galvani’s experiment led were found also in their experiments. different kinds of metal. Galvani thought Volta to invent the battery. The takeaway In summary, Lesson 5 introduced key the effect was due to the life force of the is that science is not always about learn- ideas when the pupils had suffi cient dead frogs. The presentation continued ing from new experiments; sometimes experiences to understand and accept with Allesandro Volta’s (1745-1827) dif- it is about interpreting the same experi- these ideas: a) There are two types of ferent interpretation of Galvani’s discov- ments in new ways. materials, insulators and conductors. ery, realizing that the effect was really Insulators can be electrifi ed by rubbing due to the two different metals with * Technically, a battery is composed of them, which separates positive and neg- a solution in between. He substituted two or more electric cells, but we did ative charges. In most circumstances, cardboard soaked in a salt solution for not make that distinction for the students conductors cannot be charged because the frogs’ legs, placed two different met- since most people refer to single cells as the excess charges “run away” unless als on either side and invented the fi rst “batteries.”

SPRING 2019 VOL. 27, NO. 1 29 Since the unit is intended to bring the survey given to pupils in Study 1. As with one degree of freedom). However, together core ideas about static electric- shown in Table 1, 86% of the high achiev- two pupils retained their misconception ity and circuit electricity, it links to Next ing pupils indicated that an insulator can- that an insulator cannot be electrifi ed, Generation Science Standards at both not be electrifi ed, and on the pre-test in and justifi ed their answer by claiming the upper elementary and middle school Study 2, 90% of the average achieving that an insulator cannot be electrifi ed level. And in the spirit of the NGSS, pupils indicated that an insulator can- “because it is not a conductor.” Twelve pupils develop core ideas about electric- not be electrifi ed. As shown in Table 3, of the pupils (39%) who answered that ity in the form of increasingly sophisti- the lesson was successful in helping the an insulator can be electrifi ed stated that cated and fl exible mental models through majority of pupils reject their initial mis- insulators are not only used to protect the science practices and crosscutting con- conceptions, since on the post-test only user, which researchers have consistently cepts. The emphasis of each lesson on 6% indicated that an insulator cannot be found to be pupils’ most common under- different aspects of the NGSS is shown electrifi ed. Responses about the conduc- standing of the purpose of insulators, but in Table 2. tor did not change signifi cantly, but their also to control and conduct the current. views regarding the insulator did. A chi- These fi ndings provide strong support Pre-and post-test results square test of signifi cance showed that for the electricity unit described above The 31 eighth grade pupils who were the change in response to this question to modify children’s understanding of engaged in the seven lessons described (from 90% to 6%), as a result of instruc- the properties of electrical insulators and above answered the same four questions tion, was highly signifi cant in the desired to help them develop a fl exible mental as the 100 pupils in Study 1. The results direction (chi-square = 43.6583, or model that can explain both static and of the pre-test were similar to those of 40.3646 with Yates correction, p < .001 circuit electrical phenomena.

Table 2. Relationship Between the NGSS and the seven lessons Findings & Discussion In part one of the study, 100 middle Lesson 1 2 3 4 5 6 7 school pupils at a school with the major- Performance Expectations ity of enrolled pupils performing at a high 3-PS2-3. Ask questions to determine cause and effect relationships achievement level were given the same of electric or magnetic interactions between two objects not in  four question survey that was given to contact with each other. the pupils who received the intervention 5-PS1-1. Develop a model to describe that matter is made of  in part two of the study. The majority of particles too small to be seen. the high achieving pupils (86%) claimed 5-PS1-3. Make observations and measurements to  that an insulator cannot be electrifi ed identify materials based on their properties. despite the fact that all of the pupils had MS-PS2-3. Ask questions about data to determine the factors electrifi ed pieces of glass or plastic when that affect the strength of electric and magnetic forces. they studied static electricity in elemen- Core Ideas tary school (Table 1). Electric and magnetic forces between a pair of objects do not In part two of the study, 31 eighth require the objects be in contact. The sizes of the forces depend  grade pupils at a school with the majority on the properties of the objects and their distances apart. of enrolled pupils performing at an aver- Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the age level were given the same survey as  charges, currents, or magnetic strengths involved and on the the students in part one before and after distances between the interacting objects. a seven-part instructional intervention. Practices The instructional sequence was designed Asking questions  to help pupils build a mental bridge between their understanding of static Developing and using models  electricity and circuit electricity. There Analyzing and interpreting data  was a signifi cant difference between the Constructing explanations  numbers of pupils reporting the correct Engaging in argument from evidence  response that insulators can be electri- Obtaining, evaluating, and communicating information fi ed before (3 pupils, 10%) and after Crosscutting Concepts (29, 94%) the intervention (Table 3). Patterns  Explanations given by the pupils demon- Cause and effect  strated that they did not simply learn the Systems and system models  correct answer to the question, but also Energy and matter  developed a more nuanced understand- Structure and function  ing of the nature of insulators. Twelve

30 SCIENCE EDUCATOR Table 3. Part 2 Pupils’ Pre- and Post-Test Responses to Question 1 in Percent as a continuum, with semi-conductors in the middle, and various materials at dif- Pre-Test (N = 31) Post-Test (N = 31) ferent places along the continuum. We Q1. Can an insulator be electrifi ed? % # % # believe that these and other sub-topics will Yes 10% 3 94% 29 be important in helping pupils develop a No 90% 28 6% 2 full and rich understanding of the learn- ing progression of electromagnetic phe- of the pupils (39%) who answered that and through these materials. Introduc- nomena laid out in the NGSS. an insulator can be electrifi ed stated that ing the battery, not as a source of charge Finally, we wish to highlight the impor- insulators are not only used to protect or current, but rather as a force that tance of looking to the history of science the user, but also to control and conduct separates positive and negative charges when designing curricula. The science of the current, thus providing evidence that through chemical means, helps pupils electrical phenomena began with discov- this intervention is successful in help- apply the same mental model to both eries of electrostatics in ancient Greece. ing students challenge and even change static and circuit electrical phenomena— The invention of electric circuits and dis- a common view about the properties of whether caused by rubbing an insula- covery of the relationship between elec- insulators and their functions in electric tor with a piece of wool, movement of tric and magnetic fi elds came much later. circuits. clouds in a thunderstorm, or the chemical Our pupils will need to make these tran- Nearly four decades of research have reaction inside a battery. sitions on a much shorter timescale. Cur- shown that pupils’ misconceptions about The sequence of lessons on the his- riculum developers can benefi t from both circuit electricity are deep-seated and tory of electrical science to complement the experiments of early researchers, and persistent, lasting into adulthood, even the pupils’ activities continues the work the reinterpretation of them by later sci- among the nation’s brightest STEM of prior researchers (Guisasola, 2008, entists, to gain insights into the kinds of majors at top universities. The results of and Leone, 2014). Although a primary conceptual changes that occurred during this study are supportive of a hypothesis purpose of the historical account is to the history of science, and required of put forward by several researchers (e.g. help the pupils develop their own mental our pupils if they are to achieve the per- Eylon and Ganiel, 1990; Shen and Linn, models and explanations of the phenom- formance expectations of the Next Gen- 2010; Galili and Goihbarg, 2005) that ena, it is also intended to illustrate that eration Science Standards. misconceptions about circuit electricity science does not always advance by new References may be due to a weak link in a learning discoveries and experiments, but some- Azaiza, I., Bar, V., & Galili, I. (2006). progression at the middle school level, times by reinterpreting the work of pre- Learning electricity in elementary school. when pupils are expected to develop a vious investigators. It may also have the International Journal of Science and mental model that explains both static effect of helping pupils gain confi dence Mathematics Education, 4(1), 45-71. and circuit electricity. when they learn that famous scientists of Azaiza, I., Bar, V., Awad, Y., & Khalil, M. The instructional sequence that we the past may have shared some of their (2012). Pupils’ explanations of natural tested in this study was based on a line own initial ideas. phenomena and their relationship to elec- of research extending over two decades We recognize that there are limita- tricity. Creative Education, 3(8), 1354. (Bar & Zinn, 1998; Azaiza et al., 2006; tions to this study. The sample size was Azimov, I.A. (1966). Understanding phys- Azaiza et al., 2012; Bar et al., 2016). The small, so it is diffi cult to generalize to ics. New York: Barnes and Noble relatively short seven-lesson sequence broader audiences. Also, the length of Bar, V., & Zinn, B. (1998). Similar frame- enabled the majority of pupils to see this brief report did now allow for dis- works of action at a distance: Early electrifi cation (charging) of an insula- cussion of the majority of these fi ndings. scientists’ and pupils’ ideas. Science & tor (plastic comb) as due to a mechani- For example, different pupils seemed to Education. (7), 471-491. cal force (rubbing with a piece of wool) hold different conceptions of the nature Bar, V., Azaiza, D., & Shirtz, A.S. (2016). that separates charges, leaving an excess of electrifi cation. Some thought of it as Emphasizing the role of the insulator in of charges on the insulator. That experi- a force that attracts small, light materi- electric circuits: Toward a more symmet- ence is followed by one in which they see als towards the electrifi ed object; while ric approach to insulator and conductor in that a conductor can be electrifi ed only other pupils thought of it as adding elec- the instruction of electricity. World Jour- if it is isolated, as in an electroscope. tricity to an object. The pupil’s under- nal of Educational Research, 3(1), 112. When pupils see that under certain cir- standing of the nature of materials also Borges, T.A. & Gilbert, J. K. (1999). Men- cumstances an insulator can conduct needs further work. For instance, it is tal models of electricity. International electricity (as in lightning) they have the not diffi cult for the pupils to use their Journal of Science Education, 21(1), opportunity to develop a more nuanced test circuits to identify insulators and 95–117. understanding of the electrical properties conductors, but it may be more challeng- Cardwell, D.S.L. (1995). Wheels, clocks, of insulators and conductors, and there- ing to help them see that the insulator- and rockets: A history of technology. fore of how electrical charges move on conductor dichotomy is better described New York: W.W. Norton.

SPRING 2019 VOL. 27, NO. 1 31 Cohen, R., Eylon, B., & Ganiel, U. (1983). Heller, P. M. & Finley, N. F. (1992). Variable Park, J. (2010). Analysis of students’ pro- Potential difference and current in sim- uses of alternative conceptions: A case cesses of confi rmation and falsifi cation ple electric circuits: A study of students’ study in current electricity. Journal of Re- of their prior ideas about electrostatics. concepts. American Journal of Physics search in Science teaching. 29(3), 259-275. International Journal of Science Educa- 51(5), 407-412. Kärrqvist, C. (1985). Physics teachers’ tion, 23(12), 1219-1236. Derry, T. K., & Williams, T. I. (1961). A perceptions of the diffi culty of teaching Schneps, M.H., & Sadler, P.M. (1997a). short history of technology from the ear- electricity. Research in Science Educa- MIT pupils unable to power a bulb with liest times to A.D. 1900. New York and tion, 39, 515–538. a battery. Video retrieved from: https:// Oxford: Oxford University Press. Lee, S. J. (2001). Exploring students’ under- www.youtube.com/results?search_query DuFay C. F. C. (1734). A Discourse concern- standing concerning batteries—Theories =Pupils+unable+to+light+a+bulb. ing electricity: Two kinds of electrical and practices. International Journal of Schneps, M.H., & Sadler, P.M. (1997b). fl uid: Vitreous and resinous, Philosophi- Science Education 29(4), 479-516. DOI: Minds of our own. Video, available from cal Transactions of the Royal Society, 10.1080/09500690601073350. Annenberg Learner. Retrieved from: http:// 38, 258-266. Leone, M. (2014). History of physics as a www.learner.org/resources/series26.html. Eylon, B., & Ganiel, U. (1990). Macro- tool to detect the conceptual diffi culties Schiffer, H., & Guerra, A. (2015). Electric- micro relationships: The missing link experienced by students: the case of sim- ity and vita force: Discussing the nature between electrostatics and electrody- ple electric circuits in primary education. of science through a historical narrative. namics in pupils’ reasoning. International Science & Education, 23(4), 923-953. DOI: Science & Education 24: 409-434. DOI Journal of Science Education, 12(1), 10.1007/s11191-014-9676-z 10.1007/s11191-014-9718-6. 79-94. Mayer, K.E. (2017). Students’ develop- Shen, J. & Linn, M. (2010). A technology- Faraday, M. (1833). On electrical decompo- ment and use of models to explain elec- enhanced unit of modeling static electric- sition. Philosophical Transactions of the trostatic interactions. Ph.D. dissertation, ity: integrating scientifi c explanations Royal Society, 129, 675-710. Retreived Michigan State University. Available from and everyday observations. International from: https://library.si.edu/digital-library/ EBSCO Host ED580605. Journal of Science Education, 33, 1-27. book/onelectrochemica00fara. Mehalic, M.M., Doppelt, Y., and Schuun, C.D. Shipstone, D. M. (1984). A study of chil- Galili, I. & Goihbarg, E. I. (2005). Energy (2008). Middle-school science through dren understanding simple DC circuits. transfer in electrical circuits: A qualita- design-based learning versus scripted European Journal of Science Education, tive account. American Journal of Phys- inquiry: Better overall science concept 6(2), 185–198). ics, 73(2), 141-144. learning and equity gap reduction. Journal Stocklmayer, S. & Treagust, D. F. (1994). Guisasola, J., Zubimendi, J.L., Ceberio, of Engineering Education, 97(1), 71-85. A historical analysis of electric current M., Almundi, J.M., & Zuza, K. (2008). Niedderer, H., & Goldberg, F. (1993). in textbooks: A century of infl uence on Designing and evaluating a research- Qualitative interpretation of a learning physics education. Science & Education, based teaching sequence for electrical ca- process in electric circuits. Paper pre- 3, 131-154. pacitance. Paper presented at the GIREP sented at NARST Annual Meeting in Stocklmayer, S. & Treagust , D. F. (1996). international conference, the Universi- Atlanta, Georgia. Images of electricity: how novices and ex- ty of Nicosia, Nicosia, Cyprus. Retrieved NGSS Lead States (2013). Next generation perts model electric current. International from: https://core.ac.uk/download/pdf/ Journal of science education, 32(13), 38301370.pdf. science standards: For states, by states. Volume 1. Washington, DC: National 1801-1828. Guisasola J. (2014) Teaching and learn- Academies Press. Wolf, A. (1961). A history of science, tech- ing electricity: The relations between Osborne, R.J., (1983). Towards modifying nology and philosophy in the 18th cen- macroscopic level observations and tury. New York: Harper. microscopic level theories. In: Matthews M. children’s ideas about electric current. (eds.) International handbook of re- Research in Science and Technological search in history, philosophy and sci- Education, 1, 73-82. Corresponding Author: Cary Sneider, ence teaching. The Netherlands: Springer, Park, B. (1989). A history of electricity. 3834 SE Steele St., Portland, OR 97202, Dordrecht. Hoboken, NJ: Wiley & Sons, NY. [email protected], 503-891-9263

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