1. Energy: Forms and Changes

2. Nature of Energy Energy is all around you!
You can hear energy as sound.
You can see energy as light.
And you can feel it as wind.

3. Living organisms need energy for growth and movement.
Nature of Energy
Living organisms need energy for growth and movement.

4. Nature of Energy Energy is involved when: Fireworks explode.
You ride a bicycle.
Electricity flows in a wire.
You ride a Rollercoaster.

5. Nature of Energy
What is energy that it can be involved in so many different activities?
Energy can be defined as the ability to do work or the ability to cause change.
The most common units of energy measurement are the calorie and the Joule. One calorie is equal to 4.18 joules.
Calories are the unit used to measure the amount of energy that people get from food.
Joule is the unit of measure of all forms of energy.

6. Forms of Energy Thermal Chemical PE Electromagnetic Nuclear Mechanical
The five main forms of energy are:
Thermal
Chemical PE
Electromagnetic
Nuclear
Mechanical

7. Thermal Energy
The internal motion of all the atoms that make up a substance is called thermal energy.
Thermal energy can be produced by friction.
Thermal energy causes changes in temperature and phase of any form of matter.

8. Chemical Potential Energy
Chemical Energy is stored energy found in chemical bonds.
And when bonds are broken, energy is released and when bonds are formed energy is absorbed.

9. Chemical Potential Energy
Fuel and food are forms of stored chemical energy.

10. Electromagnetic Energy
Energy in the form of EM waves.
Electromagnetic Energy is also carried by visible light, X-rays, radio waves, microwaves, UV rays, Infrared rays, and gamma rays.

11. Nuclear Energy
The nucleus of an atom is the source of nuclear energy.

12. Nuclear Energy
When the nucleus splits (nuclear fission), nuclear energy is released in the form of heat energy and light energy.
Nuclear energy is also released when nuclei collide at high speeds and join (nuclear fusion).

13. Nuclear Energy
The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse (combine) to form helium nuclei.

14. Mechanical Energy
When work (force over some distance)is done to an object, it acquires energy. The energy it acquires is known as mechanical energy.

15. ME=KE+PE Mechanical Energy
When you throw a bowling ball, you give it energy. When that bowling ball hits the pins, some of the energy is transferred to the pins.
ME=KE+PE

16. Energy Conversion
Energy can be changed from one form to another. Changes in the form of energy are called energy conversions or energy transformations.
In many energy conversions, the largest amount of wasted/unintended energy often ends up as heat.

17. Energy conversions
All forms of energy can be converted into other forms.
The sun’s energy (electromagnetic energy) through solar cells can be converted directly into electrical energy.
Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical energy) through photosynthesis.

18. Other energy conversions
In an electric motor, electromagnetic energy is converted to mechanical energy.
In a battery, chemical energy is converted into electrical energy.
The kinetic energy of a waterfall is converted to mechanical energy in turbines and then into electrical energy in a generator.

19. States of Energy
The most common energy conversion is the conversion between potential and kinetic energy.
All forms of energy can be in either of two states:
Potential
Kinetic

20. States of Energy: Kinetic and Potential Energy
Kinetic Energy is the energy of motion.
Potential Energy is stored energy.

21. Kinetic Energy K.E. = mass x velocity 2
What has a greater effect on the kinetic energy of an object, mass or velocity? Why? 2

22. Kinetic Energy The energy of motion is called kinetic energy.
The faster an object moves, the more kinetic energy it has.
The greater the mass of a moving object, the more kinetic energy it has.
Kinetic energy depends on both mass and velocity.

23. Potential Energy Potential Energy is stored energy.
Stored chemically in fuel, the nucleus of atom, and in foods (chemical potential energy).
Or stored because of the work done on it:
Stretching a rubber band (elastic potential energy).
Winding a watch.
Pulling back on a bow’s arrow.
Lifting a brick high in the air (gravitational potential energy).

24. Gravitational Potential Energy(GPE)
Potential energy that is related to the position of an object and is dependent on height is called gravitational potential energy.

25. Gravitational Potential Energy
Objects with more weight or more height have greater G.P.E.
The formula to find G.P.E. is
G.P.E. = weight x height.

26. The Law of Conservation of Energy
Energy can NOT be created nor destroyed. It can only be converted from one form to another.