THE MANY FORMS OF ENERGY

Transcription

1 THE MANY FORMS OF ENERGY Florida Sunshine State Standard Benchmark: SC.B The student identifies forms of energy and explains that they can be measured and compared. Background Information: Students will put together a simple circuit and explain the energy changes that take place in that circuit. A simple electric circuit starts with a source of electric charges, such as a dry cell. The dry cell is stored potential energy. When the circuit is complete; it will release chemical energy as kinetic energy. A wire connects the source to a light bulb or another device. A second wire connects the bulb or the other device back to the source of negative charges. An electric current is a continuous flow of negative charges. An electric circuit is a path along which negative charges can flow. Time Frame: 1 hour Material: C, D, or 6V batteries 2/pair(power source) Wires or alligator clips Paper Pencil Small light bulbs Energy Signs Socket Switch Teacher Directed Procedure Part 1 1. Elicit from students the two types of energy (Kinetic and Potential) and place the energy signs on the board with either magnets or tape. 2. Elicit from students all the different forms of energy, i.e. mechanical, solar, nuclear, sound and place these signs on the board with either magnets or tape. 3. Discuss with students under which category (KE or PE) each form of energy should be placed. Note each form could be placed in either category. 4. Give each team a kit that includes battery, wires, light bulb and fixtures.

2 5. Explain that they will be putting together a circuit. Ask them to figure out how to get the light bulb to work. 6. Once their circuit works, they should sketch and label the system that their team created. 7. Ask each team to discuss the transformations of energy that took place in the circuit. 8. At each point in their sketch where they joined together a piece of the circuit, an energy transformation took place. 9. Each group should label at least 10 places were energy transformations took place. a. Label the transformation as to, i.e. electrical to light 10. Hand out to each student one of the energy signs. Place a drawing of the circuit on the board and have students come up one at a time and place their energy sign on the diagram. 11. Each student must relate to the class why they have placed their sign at that point on the diagram. Part 2: On The Trail of Energy, (based on an article in Science & Children Magazine, Published by the National Science Teachers Association, May 2002, developed by the Bureau of Land Management, found at the following URL:

3 Student Directed Procedure: 1. You will receive a photocopy of the poster image above. To help you learn about energy forms, sources, transformations, and uses. Before beginning these activities, you may need to review with your teacher the definition of energy (the ability to do work e.g., move things, change things, heat them) and discuss the forms of energy listed below to help prepare you for the activities that follow. 2. Study the poster to find examples of potential energy (stored energy) and kinetic energy (the energy of movement). 3. Draw a chart with six columns one for each form of energy. Label the columns mechanical, chemical, radiant, nuclear, thermal, and electrical. List and classify examples of each form. Mechanical Energy: the energy of position and motion. Chemical Energy: the energy that bonds molecules together. Chemical energy is released from a chemical reaction such as burning wood, coal, or oil. Our digested food releases chemical energy for use by the body.

4 Radiant Energy: energy that travels in waves, such as sunlight, radio waves, and X-rays. Nuclear Energy: the kind of energy produced when the nuclei of atoms split or join together. Nuclear power plants split the nuclei of uranium atoms in a process called fission. The sun combines the nuclei of hydrogen atoms in a process called fusion. (Note: Other than the sun itself, no examples of nuclear energy are shown in the poster.) Thermal Energy: heat, the energy of moving and vibrating molecules. Geothermal energy is an example of thermal energy. Electrical Energy: the energy of moving electrons. Electricity is electrons moving through a wire. Lightning is another example of electrical energy. 4. Circle and label examples of different types of energy sources depicted in the poster, such as solar, gas, electric, wind. (Note: Some sources may not actually be shown, but implied, such as the gasoline in the car.) 5. Work in small groups to identify examples of energy transformations. Then, explain to others in the class the ones you've found. Part 3: Conduct an Energy Budget (based on an article in Science & Children Magazine, Published by the National Science Teachers Association, May 2002, developed by the Bureau of Land Management, found at the following URL:

5 Background: Any discussion of the energy issue must focus, at least in part, on the importance of conservation. By reducing our use of energy, it is possible to make supplies of nonrenewable fossil fuels last longer. More efficient technology can certainly play a role in conserving energy resources, but so can personal energy-saving actions. Procedure: 1. You will compile a composite list of the electric appliances that you have in your home. 2. To come up with a list, you should survey your home. Perhaps you could look through store catalogs or the newspaper to jog your memory. 3. Make a room-by-room list of household appliances. 4. Once your home list is compiled survey those who are familiar with the household of your grandparents and great grandparents generations to find out how many of these appliances were in their households when they were your age. You might interview several senior citizens from your community. 5. As a result of these activities you will no doubt be enlightened and come to understand at least one major reason why energy consumption has been on the rise in recent years. 6. According to the U.S. Department of Energy, the average household in the United States consumed around 100 million Btu (British Thermal Unit) of energy in While the overall amount of energy consumed per household

6 has declined somewhat, the amount of energy used for appliances and lighting continues to rise. 7. Consider ways that you can reduce your household energy consumption. 8. Below is a list of some common electric household appliances. Common Household Electric Appliances Air conditioner window/wall unit whole house Answering machine Can opener Clothes dryer Clothes washer Coffee maker Computer CPU Monitor Laptop Dehumidifier Dishwasher Electric blanket Electric toothbrush Fan ceiling -portable window whole house Fax machine Hair dryer Heater (portable) Iron Leaf/snow blower Microwave oven Oven Power saw Radio/stereo Range Refrigerator Television Toaster Toaster oven Vacuum cleaner VCR/DVD player 9. Check off the appliances you have in your home and then come up with a list of appliances that you and your family could live without. 10. Next, develop your own list of 10 "essential" appliances, ones you can t live without.

7 Home Learning: Part 1 Answer the following questions: 1. Can some sites have more than one type of energy? 2. Explain and justify your answer using your sketch of the circuit. Part 2 3. Complete the poster activity. Part 3 4. Conduct surveys at home; homes of relatives; or homes of neighbors. 5. Interview elderly to establish differences in energy usage. 6. Have students prepare reports on ways in which they could save energy while continuing to use these "necessities" of modern life. Assessment: Students will successfully complete Part 1, Part 2, and Part 3 and answer all analysis questions. Students may be evaluated separately on each aspect of an activity, or in any combination of the activities. For scoring, use rubrics, which may be found at the following URL Extensions: 1. Use a voltmeter to measure the voltage of a battery both before and after use. Have students predict what the reading will be, and then discuss where the energy went if Energy is neither created nor lost! 2. Investigate the properties of parallel and series circuits. 3. An extension for the mathematically inclined: Have students research the amount of energy used by their 10 "essential" appliances. They can refer to the following website for information on this subject: 4. Of course, students should keep in mind that appliances and lighting consume only about 20 percent of all the energy used in the average household. Around 70 percent is used for space and water heating/cooling. Have the class research ways in which energy consumption in these areas could be reduced. 5. In addition, the use of cars for transportation is another big energy consumer. Have students monitor the use of the family car for a week. How

8 many miles or kilometers did they travel? Could any of these trips have been accomplished by bicycle or on foot or by means of public transportation? How could students conserve some of the energy their family consumes on transportation? In some cases, energy conservation in buildings can be achieved via measures taken outside their walls. Here, students are planting shade trees near their Sacramento, California, school to help reduce the need for energygobbling air conditioning. SACRAMENTO MUNICIPAL The wood chip gasifier at Vermont's 50-megawatt McNeil Generating Station can process 200 tons of wood chips per day. Hot sand is used to heat the wood chips to about 830 C, at which point the wood breaks apart into its constituent chemicals. The result is a clean-burning gas that fuels a turbine to produce electricity. WARREN GRETZ, DOE/NREL

9 KINETIC ENERGY POTENTIAL ENERGY SOUND ENERGY

10 Thermal ENERGY LIGHT ENERGY CHEMICAL ENERGY

11 ELECTRICAL ENERGY MECHANICAL ENERGY

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