A constructivist approach to understanding the concept of Energy.
- 2. Learning objectives At the end of the lesson, you should be able to: 1. Recall the definition for energy and state its unit. 2. Iist the different forms of energy and their sources. 3. Perform simple calculations for kinetic (K.E = ½ mv2 ) and potential energy( P.E = mgh) using the formulae. 2
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- 6. Different forms of energy 6
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- 9. memonic He Keeps Eating Lightly Salted Potato Chips Heat Kinetic Electrical Light Sound Potential Chemical 9
- 10. Worksheet 10
- 11. 1. (a) What do you understand by energy? State its unit. (b) Energy can be classified into two groups; namely stored energy and ………….. . 1. (a) Light energy is produced by luminous bodies like the sun,................, and ……………. (b) …………., ………….. And batteries are sources of chemical energy. (c) …………….. Energy can be produced by generators, cells or batteries. It is a form of energy that can be converted from one form to another. (d) …………….. Is produced by vibrating objects. (e) A hot bowl of soup possesses ……………… energy. 11
- 12. 3. Match the following source of energy with the forms of energy obtained from them. Sources forms Sun Gravitational potential Fossil fuel Chemical A boy running Solar A cyclist on the top of a hill Kinetic 12
- 13. Calculations for kinetic and potential energy 1. A stone of mass 20 kg is released from a height of 5 m above the ground. Calculate the gravitational potential energy of the stone at the point of release. Take g = 10 m/s2. 2. From the Form 3 textbook pg 76 no 1: Calculate the kinetic energy of a body of mass 10 kg moving at 5 m/s. 13
- 14. Law of conservation of energy Energy can neither be created nor destroyed. Energy can be transformed from one form to the other. 14
- 15. Energy Transfer Energy Form = Where to Where? icehands HEAT
- 16. Energy Transfer Energy Form = Where to Where? appliance (TV, computer, etc) outlet ELECTRICAL
- 17. Energy Transfer Energy Form = Where to Where? CHEMICAL Fly (food) Frog (growth)
- 18. Energy Can Be Transformed Electrical energy is transferred from the wall socket to the computer. Electrical energy is transformed to sound and light energy when the computer is turned on. Electrical energy is transformed to heat energy when the computer stays on.
- 19. Summary of the lesson Energy Forms of energy Formulae for Kinetic energy and Potential energy Law of conservation of energy. 19
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