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Matter and Energy Section 3.2

Matter and Energy Section 3.2 . Science 7 Mr. Nigh. 3.1 Review- Forms of energy. 1. ______ energy is based on the movement of particles within matter _____ energy holds an atom’s nucleus together _____ energy is the energy used to move large objects.

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Matter and Energy Section 3.2

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  1. Matter and EnergySection 3.2 Science 7 Mr. Nigh

  2. 3.1 Review- Forms of energy 1. ______ energy is based on the movement of particles within matter • _____ energy holds an atom’s nucleus together • _____ energy is the energy used to move large objects.

  3. 4a.____is the energy of position or stored energy 4b. ______ is the energy of motion 5.____ is the energy from the vibration of particles in a solid, liquid or gas. 6.____ energy is stored in the chemical composition of matter

  4. Thermal • Nuclear • Mechanical • Kinetic 4.Potential 5. Sound 6.Chemical

  5. Energy Changes Forms • Plants convert energy from the sun into chemicalenergy, which is stored in the form of sugars in the cells.

  6. When an organism eats the plants, or animals who have eaten the plants, its cells release the chemical energy • Some of this chemical energy is converted into kinetic energy that a person may use to harvest more plants, hunt, or do other work.

  7. Conversions between kinetic and potential energy • Potential energy can be changed intokinetic energy and back into potential energy • Consider the illustration of a ski jumper • At first the ski jumper is on the top of the hill, giving him potential energy due to gravity. • As the skier begins moving down the hill, some of the potential energy changes into Kinetic energy

  8. When the ski jumper takes off from the ramp, some of the kinetic energy is changed into potential energy. • As the jumper ascends to the ground, the potential energy changes back into kinetic energy. • As the jumper lands and stops moving, how can he regain the potential energy he once had?

  9. Energy Conversions • Hydroelectric Power • Water held behind the dam has potential energy. • Potential energy is converted to kinetic energy when the water moves through the tunnel. • Kinetic energy is used to turn the turbines. This mechanical energy is converted into electrical energy by generators.

  10. Why does the water behind a dam have potential energy?

  11. Because of it’s position, it has potential energy due to gravity.

  12. What is the function of the moving water?

  13. It turns the blades of the turbines, which powers the generators to produce electricity.

  14. Gravity pulls water through

  15. Energy is always conserved • The law of Conservation of Energy states that energy can neither be created nor destroyed. • Although in many cases it may appear that energy is gained or lost, it has really only changed in form.

  16. Energy conversions may produce unwanted forms of energy • When energy changes forms, the total amount of energy is conserved. • The amount of useful energy is always less then than amount of total energy. • Look at the case of an electric fan

  17. Consider the energy used to power an electric fan • The amount of energy used is more than the kinetic energyof the moving fan blades. • At the same time, some of the electrical energy flowing into the fan changes into heat in the fans motor, or if the fan shakes some energy goes into unusable kinetic energy.

  18. Energy Efficiency • The measurement of usable energy after an energy conversion is known as Energy Efficiency. The more energy efficient an appliance is, the more electrical energy is turned into usable kinetic energy

  19. Describe an energy conversion you have experienced in your life. • Explain the law of Conservation of Energy in your own words. • Give an example of an energy conversion that produces unwanted forms of energy. • Suppose you are jumping on a trampoline. Describe the conversions that occur between kinetic and potential energy

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