In the Classroom
Materials Science Teaching Module as Adjunct to Introductory Chemistry Terry D. Gulden, Kirk P. Norton, Holger H. Streckert, and Lawrence D. Woolf Sciences Education Foundation–General Atomics, San Diego, CA 92121 Joseph A. Baron and Shauna C. Brammer La Jolla High School, La Jolla, CA 92037 Danine L. Ezell Bell Junior High School, San Diego, CA 92139 Roger D. Wynn Mountain Empire Junior High School, Pine Valley, CA 91962 Introductory chemistry classes at the high school or undergraduate level generally teach a number of important concepts, starting with atoms and atomic structure and progressing to molecules and molecular transformations, chemical formulas, and stoichiometry. This is followed by the concepts of chemical bonding, kinetics and equilibrium, reaction mechanisms, and thermodynamics. Gases and gas laws, and liquids and solutions, including acid–base equilibria, represent a significant portion of the introductory chemistry curriculum. Various concepts of solids are introduced, such as crystalline and amorphous solids, but with little reference to solid-state transformations and the development of “engineered materials”. Engineered materials are materials that have been fabricated or modified to satisfy specific characteristics for specific applications. Unfortunately, solid-state chemistry, especially how it relates to engineered materials vital to today’s modern technology, receives little attention. But this is an area of importance to science and technology that fascinates students and has immediate relevance to their everyday lives. We are surrounded by engineered materials in today’s world, from concrete and steel buildings to automobiles and aircraft, plastics in numerous applications, magnetic information storage, and electronic computing through silicon-based solid state chemistry. Solid state chemistry is normally part of the advanced chemistry curriculum. However, efforts to introduce materials science or materials chemistry at the early phase of the curriculum are in progress. A textbook to bring materials science into the undergraduate general chemistry courses was recently written and published after a multiyear interdisciplinary effort (1, 2). This paper describes a program developed at a private company, General Atomics (GA), as part of their Education Outreach Program aimed primarily at high-school level chemistry or general science courses. Methodology GA’s education outreach coordinator, senior management, and science education administrators from the San Diego area brought together a team of volunteer GA scientists and junior and senior high school science teachers from San Diego County to formulate hands-on teaching units. The team for the materials chemistry discipline consisted of four scientists and engineers (a chemist, a physicist, a chemical engineer, and a materials scientist) and four science teachers (two junior high school and two high school).
Over the course of a year, they developed a teaching module based on an active area of research at GA, which culminated in the teaching module: “An Exploration of Materials Science”. Within the Education Outreach Program, four other teaching modules reflecting the diversity of research at GA were developed: “Radioactivity in the Environment”, “Energy from the Atom”, “Fusion-Energy of the Stars”, and “Recombinant DNA”. The materials chemistry teaching module was expanded into a workshop, which has been presented to more than 400 teacher attendees from junior and senior high schools, most from the local area. Recently, the materials science module was presented to teachers in Orange County, California, and at the University of Denver, Colorado. It was also presented as part of an American Chemical Society nationwide satellite television seminar for science teachers (3). Materials Chemistry Teaching Module The teaching module for the Exploration of Materials Science was developed because this science field is not generally taught at the precollege level, and its multidisciplinary nature allows it to be taught as part of physics, chemistry, or biology classes. The module includes elements of chemistry, physics, mathematics, engineering, and the use of computers and emphasizes the process of tailoring or engineering materials. The teaching module enables students to produce, study, characterize, and compare different classes of materials: metals, ceramics, and polymers. Students begin by fabricating test bars of sample materials from each of the three general classes. For the metal category tin was selected because of its ready availability, low melting temperature, and nontoxic nature. Test bars are fabricated by melting tin on a hot-plate and casting it into a graphite mold. Commercially available anchor cement was selected as the ceramic to allow the use of a room-temperature cure. Samples are cast into a plastic mold using a mold release. A one-component, ultraviolet-curable polyester resin was selected for the representative polymer material because of its simplicity, ease of curing, and relative nontoxicity. The polymer samples are made by casting them into a mold with a release agent and curing them for a few minutes in direct sunlight. Because of its availability, a two-component epoxy resin will be substituted for the polyester in the future. The size and shape of the cast samples were selected to provide a convenient geometry for testing and are identical for the various samples to reduce variables. The students charac-
Vol. 74 No. 7 July 1997 • Journal of Chemical Education
785
In the Classroom terize the properties of each of the materials by noting the general appearance and performing a series of experiments to measure mechanical properties, thermal and electrical conductivity, density, corrosion resistance, and high-temperature behavior. The teaching module is designed to give the teacher maximum flexibility. It can be used in full or in part at any grade level in junior or senior high school, or in an introductory college chemistry course. Teachers have adapted it for classroom segments of anywhere between a few days and several weeks. The teachers using this module often set the students up in groups, since the multidisciplinary aspects of the experiments lend themselves to a team approach. Students are encouraged to think and solve problems as a team. For example, one team fabricates one of the types of materials, studies its chemical composition, measures its physical properties, and becomes the class expert in this type of material. The team members then write a report in the same format that a scientist would write a scientific paper. Teachers are encouraged to use this method so that students can emulate the industrial team approach to solving problems. Many of the high school teachers use the material to introduce concepts such as the scientific method, basic laboratory techniques, data analysis, scientific notation, and significant figures. Since materials science is not well known to most teachers, those who wish to obtain and use this unit have been required to attend a 3-hour workshop. These workshops have been held about once every five months at GA and at local education conferences. They are presented on weekends by both the GA scientists and the San Diego area teachers who developed the module, so that teacher attendees learn the material from both scientific and educational experts. In a typical workshop, the attending teachers listen to the experiences of those who have taught the unit at both junior and senior high school levels. They watch demonstrations to learn how to set up the laboratory apparatus and perform the experiments. The experimental kit is then discussed in detail. An agreement has been reached with the Institute for Chemical Education (ICE) at the University of Wisconsin to make the kit available through their catalog. An instructional video is being prepared in collaboration between ICE and the development team to replace the workshops. This video will also be provided by ICE.
along with two videos on materials science. This information is continually updated to demonstrate relevance to current technological advances (4). Most of this information is also provided on floppy disk in both Macintosh and PC format. The laboratory kit contains all the materials and equipment needed to perform the experiments that would not be found in a typical science classroom. The raw materials for making the test specimens are provided. The kit also includes graphite and plastic molds used to form the rodshaped specimens. Directions for reordering materials are also provided. The kits are given to the teachers free of charge. Some of the materials in the kits are donated by suppliers; others have been purchased or provided by GA. The GA scientists and San Diego teachers met after hours and on weekends to develop the module, and they do the same when they demonstrate the kits to teachers. Students have responded favorably to the materials science module. An eighth-grade earth science teacher spent three weeks using the module and said that her students “loved the experiments and felt that they were doing real science.” A chemistry senior remarked that the preparation of the test bars was the most fun that she had ever had in a classroom. Others in the class said that “it was something that was real and interesting and cool. It was about tangible things that you could relate to in every day life.” Summary A teaching module for precollege and introductory college chemistry has been developed by the Sciences Education Foundation at General Atomics. A team of scientists and secondary education teachers developed a materials chemistry teaching module that emphasizes the materials science or solid state chemistry aspect of introductory chemistry. This module can be used in part or as a unit to convey the interrelationship of processing, structure, and properties of engineered materials relevant to today’s “high tech” world. The module has been successfully implemented by more than 400 secondary education teachers as part of the chemistry or general science curriculum. Additional information about the materials science teaching module is available from the Sciences Education Foundation at General Atomics (5). Literature Cited
Teaching Module Components The experimental kit contains a laboratory kit and a print kit. The print kit includes the experimental procedure for fabricating and testing the samples, and a list of questions for the students. It provides detailed guides, written by the scientists, that cover preparation, chemical properties, mechanical properties, transport properties, and physical properties of materials and their relationship to the experiments performed in the module. Suggested objectives, strategies, and time frames are provided by the teachers who developed the unit. Recent articles on materials science from newspapers, magazines, and journals are included
786
Journal of Chemical Education • Vol. 74 No. 7 July 1997
1. Lyons, L.; Bolyard Millar, S. “You Do Teach Atoms, Don’t You”—A Case Study in Breaking Curriculum Gridlock; Lead Center: University of Wisconsin–Madison, 1995. 2. Ellis, A. B.; Geselbracht, M. J.; Johnson, B. J.; Lisensky, G. C.; Robinson, W. R. Teaching General Chemistry—A Materials Science Companion; American Chemical Society: Washington, DC, 1993. 3. Teaching Chemistry, 1994. A Materials Science Anthology; ACS Presidential Satellite Television Seminar; National Television, November 7, 1994. 4. Gulden, T. D.; Streckert, H. H.; Woolf, L. D.; Brammer, S.; Baron, J.; Ezell, D., Wynn, R.; An Exploration of Materials Science Teaching Module; General Atomics: San Diego, 1993. 5. Winter, P.; Sciences Education Foundation-General Atomics, San Diego; phone: 619/455-3335; Fax: 619/455-3379; email:
[email protected].
