edited bv
products of chemistry
GEORGE 6. KAUFFMAN CaliforniaState University, Fresno Fresno, CA 93740
The Energy Conversion Go-Arounds Kit Developed by NEED Ten Teaching Modules That Use Products of Chemistry George 6. Kauffman California State University, Fresno, Fresno, CA 93740 Robert Zafran Creative Science Products, 1868 Rosswood Drive, San Jose, CA95124 The NEED Project The National Energy Education Development INFED] Proiect was csmbl~shedbv a US Conmessional Resolution in l"980 a s part of a tenyear plan to encourage and support energy education programs in US schools. NEED links more than 8,000 schools nationwide thmugh a network of students, teachers, energy-related industries, and interested community members. I t is based on the idea that concerned, energy-literate, precollege students can be helped to become informed adults who can make intelligent energy-usage decisions and formulate wise energy policies. NEED Services and Activities NEED is a n association of energy educators that brings together the resources, experiences, and optimism of youths and adults in meaningful activities and programs. It operates through contract services provided by the Energy Extension Services (EES) organization in each state or US territory or directly with state educational departments. At the state level, students and faculties join with government and industry leaders to plan programs and statewide conferences. Services provided by NEED include newsletters, brochures, energy education workshops, presentations, and meetings for educational groups and organizations. At the local level, school-site NEED committees coordinate local community programs by promoting NEED events and energy-education activities. To establish your school within the NEED network contact your local EES representative or the NEED Project itself.' Each summer NEED wnducts several seven-day residence-based Leadership Training Camps for teachers, administrators, and students throughout the United States. All school-site NEED projects culminate in special NEED week celebrations t h a t are highlighted by NEEDay. I n 1992, NEED week began March 16, and NEEDay was March 20. Energy Exchange, a magazine for NEED students and advisors, is published three timeseach year to provide program ideas, to highlight NEED education ani\ities, and to list sources for energy education materials. The annual 'The NEED Project, P.O. Box 251 8, Reston, VA 22090, (703) 8605029.
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Journal of Chemical Education
NEED Youth Awards Program for Energy Achievement recognizes outstanding school programs and Youth Award recipients from each state who are invited to attend the NEED National Recognition Ceremonies held in Washing. ton, DC each June The Energy Conversion Go-Arounds Kit Among the educational materials provided by NEED is the Energy Conversion Go-Arounds Kit that was created and developed for students in grades 6 1 2 and for adults by Robert Zafran, NEED Educational Consultant, and Gerard Katz, NEED Project Director. The kit comprises ten modules that use commercially available products. The modules are designed to teach energy generation, conversion. and utilization orocesses usine self-directed and self-paced, tabletop acti4ties. Each mo&le contains a "DO THIS" section that demonstrates a oarticulw tvoe of energy process. A directed, hands-on, activity-based approach is coupled with a student-oriented instructional sheet that provides background and discussion information explaining the process involved. All materials necessary to complete the tasks in each module are included in the kit, except common laboratory equipment and some grocery store items. The modules cdn supplement existing units in energy education or can be used as a n independent unit.
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Uses of the Kit
The self-paced, self-teach modality of the Go-Arounds Kit has proved to be effective with a wide range of students. With thought-provoking questions and novel activities, students are guided through the generation, conversion, and utilization of energy resources. The intent of each Go-Arounds Kit module is to acquaint students with the different forms of energy and the processes involved in the application of energy resources. Thus, exhaustive technical explanations are not necessarily contained in each module. The kit was selected by a National Science Teachers Association (NSTA) committee for presentation a t the first US-Soviet Conference of Science Teachers. This conference, jointly sponsored by NSTA and the Soviet Academy of Sciences, was hosted by Moscow's Lomonosov State University from July 31 to August 2, 1991. The Energy Conversion Go-Arounds Kit was presented to eighty Soviet
and American teachers by Robert Zafran, who also made another presentation a t the conference illustrating the use of computer-interfaced chemical laboratories in high school chemistry courses. Lower-ahilitv students who have used the Go-Arounds Kit have expehenced minimal difliculty in understanding the concepts and applications involved. Students in atrisk, drop-out prevention programs have also succeeded in mastering the learning objectives of each module and seem to enjoy the self-teach learning techniques that are used. The purpose of this article is to acquaint the reader with the existence of the NEED Project and the availability of the Go-Arounds Kit: detailed directions and ex~lanatious for each module are' provided with the kit. ~ r i e summaf ries of each module are given below. The existing modules in the kit will be complemented by additional modules being developed.
an 8 cm x 12 cm polypropylene pouch. Flexing a stainless steel disk ("trigger") contained in the pouch provides the "shock" that disturbs the solution's metastable eauilibrium.The rapid exoth~rmiccrystallizationthat occurs produces heat with temoeratures as hieh as 54.4 'C (130 'F.: the temperature reniains above 37.g 'C (100 'F) for more than three hours. In this module students investigate this reversible, ohvsical reaction and its concomitant heat effects. The ~ e " a Solution, t which is used by athletes and outdoor sportsman to combat cold. is "recharged" bv heatine the p'ack in boiling water (a rhicrowaveable zap pack is now available) and cooling the resulting supersaturated solution. Other systems that depend on the reversible conversion from a hydrate to a solution have been developed to use stored heat from the sun during the day thacis released during nighttime.
The Modules Mechanical Energy to Heat Energy (Rubber Bands)
Chemical Energy to Heat Energy (The Grabber)
This module consists of several experiments in which rubber bands are stretched and contracted and then heated and cooled. According to Le Chitelier's principle, when rubber. a loosely cross-linked polymer, is unstressed (unstretchedj, it releases heat whenstretched and absorbs h e a t when i t contracts. Conversely, when stressed Isrretched,, if heated, it contracts. K%en cooled, it expands. If a newly stretched rubber band is pressed to onc's forehead. the heat generated can bc rendilv detfctcd. Since the arrangement of the uncoiled, aligned polymer chains is more orderly than the disordered, unstretched random coils, the stretched polymer chains are said to have decreased entroov or disorder. This entroov increases when the tension in the stretched rubber handis released. Thus. the freshlv unstretched rubber band will feel cool when' pressed toutheforehead or lips.2 This module gives students a clear example of Le Chitelier's principle as well as an introduction to thermoplastic polymer characteristics.
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Mechanical Energy to Light Energy (The No-Battery Flashlight)
The No-Battery Flashlight is a hand-held, 15-cm long, manually operated flashlight, commonly called a "survival light". By squeezing a lever in the handle, the mechanical motion created is used to rotate a cylindrical magnet within a coil. The electricity resulting from electromagnetic induction is supplied to a 5-W bulb, which in turn provides the illumination. Students exploring this module are in fact "experiencing" a microscale version of a large-scale electrical generating system, which also operates on the principles of electromagnetic induction. Chemical Energy to Heat Energy (The Heat Solution)
The well-known propensity of sodium acetate (NaC2H302)to form supersaturated solutions that liberate heat on c1ystallizing3~~ has been ingeniously applied in a reusable heat pack commercially available as The Heat Solution (Flinn). A solution of nontoxic supersaturated sodium acetate trihydrate (NaC2H302.3H20) is encased in 'Kauffman, G. B.; Seymour, R. B. J. Chem. Educ. 1990,67,422. 3Kauffman, G. B.: Hagopian, J.: Ebner, R. J. Coll. Sci. Teaching 198511986. 15,236. %hakhashiri. B. 2. Chemical Demonstrations: A Handbook for Teachers of he mist^ University of Wisconsin: Madison, WI, 1983; Vol. 1 , (a)pp 27-30; (b)pp 146152.
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The Mycoal Grabber Mini-Mini Heater is an odorless, nontoxic, disposable hand warmer. It is a 5 cm x 7 cm pad impregnated with a dry mixture of various substances iron powder water for heat dispersion cellulose for water release vermiculite for insulation activated carbon for oxygen absorption salt to prevent freezing The oxidation of the iron powder 4FeM + 30,(g) 3 2Fe203(s) is initiated by atmospheric oxygen when the pad is exposed to the air. The suhsequent production of iron(II1) oxide in this highly exothermic reaction produces and maintains a temperature of 57-69 'C (135-156 'F) for about seven hours if the flow of oxygen is somewhat restricted, such as in a pocket or glove. The used pad can be safely - disoosed of in n&al t r a s i systems. With the consumable Grabber heat pack in this module students can easily initiate a safe and readily ohsewable chemical reaction that produces large amounts of heat. A
Potential Energy to Khetic Energy (The Jumping Disk)
The Jumping Disk is a 2.5-cm circular disk composed on opposite sides of two different metals-stainless steel and nickel-with different thermal coefficients of ex~ansion. The differential expansion property of bimetallic materials explored in this module is commonlv used in thermostatic &itches. The disk is warmed in (he palm of the hand, rubbed briskly, pressed until it clicks, and then placed on a hard surface.-& the disk cools, i t jumps into the air because the difference in the thermal coefficients of expansion causes one side to contract more than the other. In this module the conversion of stored potential energy to kinetic energy clearly illustrates the principle of differential expansion. The more the disk is deformed, the larger the potential energy, and the higher the disk jumps. Using this module, students investigate potential (stored) energy and its suhsequent conversion to kinetic energy. Chemical Energy to Light Energy (Lunker Lights)
Lunkcr Lights are miniature (4-~mlongl Cyalume lightsticks that glow when uctivated. They are used as lures for nighttime sport fishing. Achemical reaction is i ~ t i a t e dby bending a glass ampule containing hydrogen peroxide, which reacts with the diphenyl oxalate ester stored inside Volume 69 Number 5
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Heat Energy to Mechanical Energy (The Thermobile)
The "2"Meter connected to a single-cell "Macintosh"battery. a clear polypropylene tube. Then l,2-dioxetanedione is produced as an intermediate. I t transfers energy from the reaction to 9,lO-bis[phenylethynyllanthracene,a fluorescent dye that emits light energy when the excited dye returns to the ground state." The nontoxic by-products of the reaction can be easily disposed of in normal trash systems. With this module students investigate the effects of heat on the brightness and availability of emitted light. Students can readily observe the effect of temperature on the rate of chemical reactions by comparing the relative levels of illumination from Lunker Lights a t different temperatures to a reference Lunker Light kept a t room temperature. Larger versions of the Lunker Light have many applications in outdoor camping and emergency lighting, as well as in guiding military aircraR during night landings on aircraft camers. Light Energy to Electrical Energy (The PV Cell)
In this module students investigate the eflect of light intenritv on the current on~ducedbv solar ohotovultaic II'VI . . cells using a "Z"meter, which is a n adjustable milliampere meter developed by Robert Zafran (See Fig. 1).PV cells directly convert light photons to electrical energy by the photovoltaic effect. When radiation is allowed to strike the PV cell surface, the internal electrons of the PV material are stimulated. If the stimulating radiation is high enough, electron-hole pairs are generated throughout the P-N junctions in the material, thus generating a voltage across the junction. The generation of voltage in this manner is known as the photovoltaic effect. The PV cells in the kit are constructed from many small cells of silicon that are assembled in arrays mounted on a plastic or aluminum substrate forming a PV panel. Since the efficiency of the panels is typically less than 20%, many panel; are required to produce large amounts ofrlectricity. However.. PV oanels f i d evemdav " " use in low-voltaee. - . lowcurrent consumer produets such as clocks, radios, and calculators.
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'Kauffman, G. 0.; Mason, S. W.; Seymour, R. €3. J. Chem. Educ. 1990, 67,198. 'Storev. R. F.: Sevrnour. R. 0.: Kauffman.G. B. J. Chem.Educ..in press. 368
Journal of Chemical Education
A wire of Nitinol-an alloy of 50% nickel and 50% titan i p n o t only changes its shape when heated but also changes to a predetermined shape that was "programmed" into the wire when it was manufactured. This so-called "shape-memory effect" allows the wire to be deformed on heating or cooling and to return to the shape that it "remembered". In this module students investigate the effects of heat on the shape-memory properties of Nitinol wire with a device called a-Thermobce, which is a "heat engine" operating on the energy in hot water. Students using the Thermobile explore the effects of heat on two metallic alloys: a brass pulley and Nitinol wire. The Thermobile has a single strand of Nitinol wire wound around a two-pulley system with one brass pulley and one plastic pulley. When the tip of the brass pulley is inserted in 50-75 'C (122-167 'F) water, heat energy is transferred to the Nitinol wire. One section of the Nitinol wire contracts because of the "memory" effect, and the resultant torque forces the pulleys to rotate. The Thermobile directly converts thermal energy to mechanical (rotational) energy, and small engines using the Thermobile principle have been developed. These engines are used to pump water in an active, solar hot-water heating system using the hot water as a heat source to drive a pulley system in the engine. The Nitinol pump engine needs no outside source of power. Thus, the entire system is "self-contained". Technological advances in memory-effect alloys may s Drateventually provide meater capacity heat e n..~ n e for tical u s e i i low-po~cr,mech'anick~energy a p p ~ ~ c a i ~ o n s . Other commercial applicationit of Nitinol include bearings. automatic shut-in Gaives, large antenna arrays, and sun: glass frames. Chemical Energy to Electrical Energy (The Electrochemical Cell)
In this module students construct a battery by inserting copper and zinc electrodes into a piece of fruit or acidic liquid, which provides the electrolyte that transfers electrons from the cathode (Cu) to the anode (Zn). The Zn electrode is oxidized, while Cua ions are reduced at the Cu electrode. Zn + ZnZt+'2e cu2++ 2e + Cu
The characteristics of this simple electrochemical cell are investigated using the "Z" meter to measure the relative amounts of current generated by the cell. This module provides several activities for students. direct observation of the composition of an electmchemical cell the use of differentelectmlytes determination of relative pH values .determining the effect of varying the lengths and thicknesses of electrode material exploration of the chemical activity of different metallic and nonmetallic electrodes Potential Energy to Kinetic Energy (Happy and Unhappy Balls)
Students use this module to investigate the properties of a pair of solid, black, 2.5-cm-diameter polymer balls that look i d e n t i ~ a l .The ~ . ~more rigid or "happy" ball is made of polychloroprene (neoprene), while the softer or "unhappy"
ball is made of polynorbornene (Norsorex). A special and readily observable property of the "unhappy" ball is its rel u d v e to bounce due to its relatively rapid dissipation of kinetic energy. This property intrigues students and quickly prompts them to ascertain other physical differences between the two balls. Differencesthat can be examined include coefficient of friction, density, kinetic energy dissipation rate (bounce), and thermal coefficient of restitution. Neoprene, from which the "happy" ball was made, is a good general-purpose polymer rubber. However, its high cost has limited its use to applications that require its special properties, such as resistance to oils, chemicals, air, ozone, heat, and flame. Norsorex, from which the "unhappy" ball was made, is a synthetic elastomer developed during the late 1970's. It is used in oil-spill recovery, sound
insulation, vibrational damping, amusement park games, seals, and gaskets. Obtaining the Kits The complete Energy Conversion Go-hounds Kit is available from the NEED organization' a t a cost of $175.00. Individual modules are not sold separately, but some of the individual products used in the kit can be purchased from science supply companies and retail outlets. Further information on commercial sources of the products contained in the Energy Conversion Go-hounds Kit and detailed instructions on how to construct and use a "Z" Meter can be obtained from Robert Zafran. Acknowledgment The authors thank the reviewers for numerous useful suggestions for improving this article.
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