Students assume the roles of eight scientists to explore the atomic model

Jennifer L. Craft and Jacqueline S. Miller n this project, high school chemistry students investigate atom- ic structure from a historical perspective. Assuming the perso- nas of eight legendary scientists and their assistants, students stage a mock gathering to explore the evolution of the atomic model. This role-playing activity may also serve as a template Ifor weaving the rich history of science into other subject areas. 24 The Science Teacher Project and rationale To prepare for the gathering, students had to re- Many students fail to realize that science is not an search the personal stories and discoveries that led to absolute truth but a human endeavor, full of inter- the development of the modern atomic model. During esting discoveries, stories, and missteps. Scientific the first week, teams were given one 50-minute plan- knowledge is ever evolving, questions of yesterday ning period to begin researching their scientist and to inform the experiments of today, and seemingly small develop a strategy for completing the project. Dur- advances (even blunders!) can be instrumental in ing the second week, teams were given an additional shaping our views of the natural world. The National 50-minute planning period to finalize project details, Science Education Standards (NRC 1996) recognize the practice presentations, and ask questions. All other efficacy of teaching science within the context of his- research and preparation were completed outside the tory, emphasizing the evolution of concepts, models, classroom (in lieu of regular homework assignments and theories. By studying science in a historical con- for the two-week period). During the third week, each text, students view themselves less as spectators and group met with me outside of class to go over questions more as participants in this human quest for truth related to difficult theoretical or experimental concepts and understanding. and presentation content. The development of the modern atomic model My classes delivered their presentations in one 80- marks one of the greatest accomplishments and most minute class period (our designated laboratory day). interesting scientific stories of the last 200 years. De- If this time option does not exist, I recommend devot- signed as a part of Foundation Science (EDC 2005)—a ing two 50-minute class periods to these presentations, three-year high school science curriculum now in de- allowing time for both the presentations and 2–3 velopment at Education Development Center, Inc.— minutes for questions, as my students were markedly the project outlined here asks high school chemistry curious about the historical characters and their dis- students to explore atomic structure from a historical coveries. Students were given one week from the day perspective. Assuming the personas of eight legend- of the presentations to assemble and submit a news sto- ary scientists and their assistants, students stage a ry on Thales’s gathering (Figure 1). While the precise gathering to probe the evolution of the atomic model. format of this independent, written assignment was Students research the experimental evidence for left to students, a guideline of 500–1,000 words was set the construction of this model as well as the lives and for news reports and feature articles. thought processes of the scientists involved. Each sci- entist group presents their research to the rest of the Presentations class, delving further into the details and complexities Playing the part of the Greek philosopher Thales (com- of atomic theory. Presentations are given in their his- plete with a toga and gray wig), I began the meeting by torical, chronological order, underscoring the incre- introducing the life and work of Thales, including his mental nature of scientific advancement. The project hypotheses on matter: “The world appears to be filled culminates in individually written news stories about with things that are all very different from each other. the “meeting of the minds,” an assignment that al- However, I believe there is an underlying structure that lows students to weave science history, modern atom- connects all matter. Perhaps all substances are just combi- ic theory, and their own twist on events that might nations of a few simpler substances.” I went on to outline transpire if deceased scientists could converse. Thales’s incorrect identification of water as the common, basic building block of matter and fundamental questions Project management and timeline to be addressed at the gathering (e.g., What is the nature Two weeks prior to the presentation date, I introduced of matter? Is there an underlying structure that connects the project, timeline, and expectations (Figure 1, p. all matter?). One student recorded these questions on the 26) to my four chemistry classes (mix of grades 10 and board to reinforce key ideas and allow time for the class 11). Following submission of their top three scientist to reflect on the day’s agenda and objectives. choices, I divided students into teams of two or three Thales’s welcoming remarks were followed by pre- and assigned the roles of scientists such as John Dalton, sentations given by the eight scientists and their as- Marie Curie, Erwin Schrödinger, and their assistants sistants. Many groups began by having the assistants (Figure 2, p. 27). They had been summoned, students outline the background and scientific achievements of were told, to attend a historic gathering organized by their mentor scientist. The scientists then presented the pre-Socratic Greek philosopher Thales. Thales, their experiments and discoveries related to the atom believed by many to be the founder of natural philoso- and its internal structure. Groups were encouraged phy, was the first person to suggest that all matter was to supplement their presentations with visuals (Pow- unified by a common building block, although he in- erPoint presentations, posters, or three-dimensional correctly identified that building block as water. models) and interactive activities (Figure 2). Student

February 2007 25 F I G U R E 1 Student project outline. Background question/answer sessions were often accompanied by brief You are a scientist or scientist’s assistant, and you have been summoned to attend a historical teacher summaries to under- gathering organized by Greek philosopher and scientist Thales. As a scientist of the 19th or 20th line important concepts and century, you will need to imagine traveling far back in time to 540 BC. The central question events, clarify connections, to be addressed involves the nature of matter: Is there an underlying structure that connects and prompt students to reflect all matter? Thales has chosen you, the experts of the “modern” world, to attend his gathering on the progression of scientific and share your stories. theories and models. We end- ed our meeting with a round Project overview of applause for all attendees Your team will prepare a five-to-eight minute presentation on your scientist’s life, scientific and words of gratitude from a achievements, and contributions to our understanding of matter or atomic structure. newly enlightened Thales. Assuming the roles of scientist and assistants, your team will share personal stories and your piece of atomic history at Thales’ gathering. At the conclusion of the gathering, you News stories will compile and submit a news story on the event (one story per student). At the conclusion of Thales’s gathering, I asked students to Part I: The presentation individually assemble a short ◆ Begin by researching your scientist’s life, scientific achievements, and contributions to outline of major events in our understanding of matter or atomic structure. When and where was your scientist atomic history, written in the born? Where was your scientist educated? What experiments led to your scientist’s form of a newspaper article discoveries? Does your scientist’s model of the atom fit with experimental data? How or other newspaper feature. did the findings of your scientist advance our understanding of atomic structure? Students based the articles on their meeting notes, the ◆ Explore a variety of sources to obtain information (e.g., textbooks, library books, abstracts, and postmeeting periodicals, the internet). Be certain to properly document your sources. interviews with individual ◆ Assemble and submit a one-page abstract highlighting important ideas and facts covered scientists (obtained outside of in your presentation. Document all sources in a properly formatted bibliography. This ab- class). While the presentations stract will be distributed to all members of the class on the day of the presentations. allowed students to focus on

◆ Use of visuals (PowerPoint, posters, or three-dimensional models) and interactive individual lives and achieve- activities is encouraged. ments, the news-story assign- ment forced them to reflect ◆ Try to put yourself in the shoes of your scientist or assistants. Although not required, on and synthesize big-picture costumes may be used to enhance your presentation. ideas: The intersecting stories of eight individuals, the pro- Part II: The news story gression of scientific thought, ◆ On the day of the gathering, take detailed notes on the event. What was the order of and our modern understand- events? What did each scientist contribute to our modern atomic model? How did the ing of atomic structure. various participants interact?

◆ Decide on the format of your news story. PHOTO COURTESY OF THE AUTHORS While accuracy of historical and scientific information is essential, the format of your story remains flexible. For example, you may choose to convey the story in a standard news report, a feature article, an editorial, a gossip column, or a comic strip.

◆ Use information provided in the abstracts to supplement your notes; should you need additional information, feel free to interview other scientists or their assistants after the gathering.

26 The Science Teacher F I G U R E 2 The scientists (teacher handout).

Contributions to Examples of visuals and Scientist Key achievements understanding the atom interactive activities All matter is united by a common Founder of school of natural philosophy; underlying structure; water is the Host of the Thales introduced mathematics and astronomy common building block from which all scientific gathering to the Greeks matter is made (an incorrect hypothesis)

Elements are made of atoms; atoms Interested in meteorology and of given elements have unique atmospheric chemistry; known as father Ball-and-stick models of characteristics; atoms combine in John Dalton of modern atomic theory; developed compounds with varied small, whole-number ratios to form four postulates describing relationship atomic ratios compounds; different compounds between elements and compounds contain atoms in different ratios

Observed patterns among elements; Display of periodic tables Dimitri credited with developing modern Elements can be organized by their through time; Periodic Mendeleev periodic table; predicted properties physical and chemical properties Table Activity* of new elements

Discovered radium and polonium; Radiation is linked to the internal Photos of radium and used x-rays to examine injuries in WWII; Marie Curie structure of the atom, not to the polonium; photos of won two Nobel Prizes (for physics in 1903 arrangement of atoms in a molecule radiation-damaged tissue and chemistry in 1911)

Discovered electron; contributed to Cathode ray tube J.J. Small, negatively charged electrons development of mass spectrometer; demonstration; diagram Thomson are contained within atoms received Nobel Prize for physics (1906) of cathode ray tube

Coined terms for alpha, beta, and gamma Tiny nucleus contains majority of Ernest rays; discovered nucleus; used radioactive atom’s mass; the nucleus contains Diagram of gold Rutherford decay products to probe the atom; won positive charge; electrons revolve foil experiment Nobel Prize for chemistry (1908) around nucleus

Theorized that electrons occupy shells or energy levels; explained that elemental properties are related to occupancy of Illustration of Bohr’s outermost electron shells; showed that Electrons orbit the nucleus in Niels Bohr atomic model; line spectra electrons can jump to higher shells with discrete paths of various elements light absorption and fall back to lower shells with light emission; won Nobel Prize for physics (1922)

Developed Uncertainty principle; spoke Werner Electron locations are best described against use of atomic bomb in WWII; Maps of probability density Heisenberg by areas of probability won Nobel Prize for physics (1932)

Merged Uncertainty principle and concept Electrons are housed in Erwin of wave-particle duality; devised famous Models of s, p, and d atomic orbitals of various Schrödinger wave equation to describe atomic orbitals; atomic orbitals shapes and energies won Nobel Prize for physics (1933)

*See chemistry module of Foundation Science (EDC 2005). February 2007 27 F I G U R E 3 Sample scoring rubric for group presentations.

Criteria 1 2 3 4 Points Students did not Students addressed Students addressed Students addressed address project goals some project goals the majority of all project goals and and demonstrated and demonstrated project goals and Content demonstrated superior little familiarity with familiarity with demonstrated good command of factual/ factual/technical factual/technical command of factual/ technical information. information. information. technical information.

Presentation followed Presentation was Presentation was reasonably logical unorganized and somewhat organized Presentation flowed Organization sequence and incomprehensible but sometimes difficult easily and logically. demonstrated few to audience. for audience to follow. gaps in flow.

Delivery was reasonably Delivery was Delivery was unclear Delivery was clear, clear and audible to reasonably clear and and inaudible to most. polished, and audible. most. Students used audible. Enthusiasm Students read from Students kept audience Delivery minimal eye contact and eye contact were notes and failed to engaged throughout and displayed minimal good, but delivery show interest in with enthusiasm and enthusiasm or interest could have been their work. eye contact. in their work. more polished.

Students consulted few Students consulted Students consulted resources and failed several resources and many resources and Students consulted few to conduct thorough, conducted detailed conducted thorough, resources and failed detailed research. research. Students detailed research. to conduct adequate Students failed to made good attempts Students effectively Research and research. distill information to distill relevant distilled relevant resources relevant to assignment. No sources were information. information. referenced in the References were Sources were generally All sources were desired format. incomplete and/or referenced in the accurately referenced did not use the desired format. in the desired format. desired format.

Students used Students used many Students made few visual aids. visual aids, but effective use of visual Students did not use Visual aids Relationships between connections between aids to complement visual aids. visuals and content visuals and content content and enhance were not apparent. were not optimal. interest.

Student was Student was cooperative and Student was Student was reasonably cooperative, Cooperation assumed many uncooperative and did cooperative and completed assigned and leadership tasks within not complete his/her completed most tasks, and assumed participation* group. Student’s portion of project. assigned tasks. some leadership tasks contributions exceeded within group. responsibilities to group. Total points /24 *Assigned to individual group members through a combination of peer evaluations and teacher observations.

28 The Science Teacher Although students were not initially enthusias- role-play, and their creative news coverage of the tic about the writing exercise, many were pleasantly day’s events. In the course of our mock gathering, surprised by how much they enjoyed creatively as- students moved from the simplistic “solar system” sembling stories and concepts. Submissions ranged model of the atom found in middle school texts from factual news reports to humorous editorials to (with planetary electrons circling a sunlike nucleus) elaborate comic strips. As demonstrated by the quality, to a much more sophisticated, realistic model based vitality, and ingenuity of student work, my chemistry on experimental evidence gathered by the scientists classes clearly enjoyed a memorable and worthwhile studied. Moreover, they began to comprehend the dif- learning experience. ficulties involved in interpreting experimental data, constructing models, and revising these models to Project assessment and extensions coincide with new evidence. Students were evaluated on the basis of both their The student-initiated debates that followed Tha- group presentations (50%) and individual news sto- les’ gathering were perhaps the most revealing: How ries (50%). Points for group research and presenta- has knowledge of atomic structure changed since tions were assigned using the scoring rubric in Figure Schrödinger’s time? What types of experiments are 3. (At the conclusion of the project, students rated scientists conducting to learn more? Would the cur- fellow group members’ contributions in order to bet- rent atomic model undergo changes or refinement ter inform my evaluation of the cooperation and par- during their lifetimes? I was thrilled to see students ticipation component.) Individual news stories were delving beyond a basic textbook understanding of the assessed using a rubric of a similar style with compa- atom, searching for more answers, and thoughtfully rable criteria (content, organization, format/style, and questioning what lies ahead! originality/creativity). From the riveting personal story of Marie Curie Of the 54 students who participated, 87% rated the to the complex atomic orbitals of Erwin Schrödinger, project as good or excellent through anonymous evalu- the knowledge each group gleaned through their ations. Several students commented that they enjoyed independent research afforded a sense of pride the personal stories behind what could have been a and accomplishment. For groups who encountered somewhat stale topic. Some reported that exploring more difficulties, a deeper appreciation of scien- the intricacies of a particular experiment or “mind- tific discovery and process no doubt was achieved. blowing idea” was challenging and fun. Other students All students seemed to leave the gathering with a enjoyed wearing costumes, creating PowerPoint pre- heightened awareness of science as a human endeav- sentations, building models, and conversing with their or—not separate from society but rather an integral peers. Although costumes should not be required, they part of society. ■ may significantly enhance the overall experience of the gathering. Students seemed more apt to “become” their Jennifer L. Craft ([email protected]) is a chemistry scientists if they were dressed accordingly. Costumes and physics teacher at Noble and Greenough School and a re- ranged from simple lab coats to wigs and bottle-cap searcher at the Center for Science Education at Education Devel- spectacles (see the picture of students on p. 26). opment Center, Inc. (EDC) and Jacqueline S. Miller (jsmiller@edc. While the project described here is intended for org) is the principal investigator of Foundation Science and a high school chemistry students, it could easily be senior scientist at EDC in Newton, Massachusetts. adapted to fit a lower-level physical-science course. No prior knowledge of atomic structure is required, Acknowledgments although teachers may wish to give additional guid- The authors would like to thank colleagues at EDC and Noble and ance to lower-level students encountering more ad- Greenough School for continued support and encouragement. Spe- vanced concepts for the first time. This type of activ- cial thanks to Irene Baker and Kerry Ouellet for help in the devel- ity could be used to explore the rich history of science opment of this project, Christine Brown and Millicent Lawton for in other subject areas, as well. For example, Gregor reading this manuscript, and Sheila McElwee for creative insight. Mendel might convene a gathering of Franklin, Funding for Foundation Science is provided by the National Science Watson, Crick, McClintock, Pauling, and others who Foundation under grant No. ESI-0101798. participated in the discovery of the DNA structure and the modern understanding of the genetic code. References Education Development Center, Inc. (EDC). 2005. Foundation sci- Final thoughts ence: A comprehensive curriculum. Center for Science Education at Overall, my experience with this project was over- EDC. http://cse.edc.org/curriculum/foundationscience/default.asp. whelmingly positive. Students impressed me with National Research Council (NRC). 1996. National science education their animated presentations, their willingness to standards. Washington, DC: National Academy Press.

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