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Energy exists in different forms

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Presentation on theme: "Energy exists in different forms"— Presentation transcript:

1 Energy exists in different forms
Chapter 3.1 Energy exists in different forms

2 Energy All forms of energy cause changes to occur
Wind causes flag to flutter Light bulb gets hot and glows You pick up a tennis racket, change position Hit tennis ball The ability to cause a change Energy takes many different forms and has many different effects.

3 Forms of Energy Scientist classify energy into many forms pg 73
Mechanical Energy Sound Energy Chemical Energy Thermal Energy Electromagnetic Energy Nuclear Energy Each form causes change in a different way.

4 Mechanical Energy Energy that moves objects Example
Energy used to put a book on a shelf Energy used to turn a key

5 Sound Energy Sound results from the vibration of particles in a solid, liquid or gas Sound cannot travel through empty space

6 Chemical Energy Energy that is stored in the chemical composition of matter Amount of energy Depends on types of atoms Depends on arrangement of atoms Examples When wood or gasoline burns chemical energy produces heat Cells use chemical energy that our bodies store from the food we eat

7 Thermal Energy Total amount of energy from the movement of particles in matter Energy of the motion of atoms and molecules

8 Electromagnetic Energy
Energy transmitted through space in the form of electromagnetic waves Can travel through empty space These waves include Visible light X-rays Microwaves Sun releases large amount that is absorbed by Earth

9 Nuclear Energy The center of an atom, its nucleus, is the source of nuclear energy When a heavy atoms nucleus breaks apart energy is released When the nuclei of two small atoms join together energy is released

10 General Types of Energy
All forms of energy can be described in terms of two general types of energy Kinetic Energy – energy of motion Increases as mass increases Increases as speed increases Potential Energy – stored energy Due to position (pg 76) Gravity, stretching, compressing chemical composition Energy stored in food, fuel in rocket engine Potential and Kinetic Energy demonstration

11 Energy can change forms but is never lost
Chapter 3.2 Energy can change forms but is never lost

12 Energy Changes Form How does energy change form?
Example – a match PE is stored in the chemicals on the head of the match The flame releases that energy as light and heat Conversions between PE and KE Examples – roller coaster, ski jumper, skate boarder Using Energy Conversions Water stored behind a dam is changed to electrical energy Pg 80 for other examples

13 Law of Conservation of Energy
States that energy can neither be created nor destroyed. It may appear that energy is lost or gained It only changed form Example 2nd example Useful energy is always less than the total amount of energy Energy conversions may produce unwanted forms of energy Electrical energy may be converted into unwanted sound energy – (ie) a fan

14 Energy Transfer Examples

15 Energy Efficiency Measurement of usable energy after an energy conversion High efficiency Converts greater percentage of energy into the desired form Low efficiency Converts a greater percentage of energy into an inefficient form

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