1. Chapter 5: Energy: Forms and Changes

2. Energy is the ability to do work
Energy is the ability to do work. Energy can be in many different forms and is all around us!
Living organisms need energy for growth and movement. The energy for these processes comes from the foods we eat.

3. The 2 states of energy are:
1. Kinetic Energy
2. Potential Energy

4. Kinetic Energy is energy of motion
Kinetic Energy is energy of motion. The faster an object is moving, the more kinetic energy it has.
The word “kinetic” means motion.

5. Kinetic energy is directly related to the velocity of an object.
Formula: K.E. = (mass x velocity2) / 2
According to this formula, if either the mass or velocity of an object increases, the amount of kinetic energy increases!

6. Potential Energy is energy of position.
When an object is located in such a position that movement could easily occur, it has a great potential energy.
Example: stretched rubber band
Potential Energy is stored energy!

7. Potential energy that is dependent on height and weight is called gravitational potential energy. The more an object weighs and the higher up from the ground it is, the more G.P.E.
Formula: G.P.E. = weight x height

8. Energy, like work, is measured in Joules.
Energy appears in many forms. The 5 main forms of energy are mechanical, thermal, chemical, electromagnetic, and nuclear.

9. Mechanical Energy
Mechanical energy is energy associated with motion. When any type of matter is moving, it has mechanical energy!
Examples:
water moving
wind blowing
Sound

10. Thermal Energy
Thermal energy, or heat energy, is created by the movement of atoms in a substance. The faster the atoms move, the more thermal energy they have.
Thermal energy usually
results from friction.
Thermal energy causes changes in the temperature and phase of any form of matter. Example: melting of ice

11. Chemical Energy
Chemical energy is energy that is stored in chemical bonds. This energy can either be absorbed (endothermic) or released (exothermic).
Examples:
burning of fuel
digestion of food

12. Electromagnetic Energy
Electromagnetic energy is energy associated with moving charges. This energy can be carried by electricity, light, X-rays, radio waves, and laser light.

13. Nuclear Energy
Nuclear energy is energy produced when the nucleus of an atom splits (Fission) or when two nuclei join (Fusion).
Nuclear energy is the most concentrated form of energy.

14. Energy has the unique ability to change from one form to another or move from one object to another. Changes in the forms of energy are called energy conversions.

15. The 2 most common energy conversions are:
Kinetic  Potential
Potential  Kinetic

16. Other Examples of Energy Conversions:
photosynthesis (electromagnetic  chemical)
Solar panels (light  electricity)
Motors (chemical  mechanical)
Batteries (chemical  electromagnetic)

17. The Law of Conservation of Energy
When energy is converted from one form to another, the total amount of energy stays the same.
Energy can neither be created nor destroyed!

18. Einstein’s Experiment
In 1905, Albert Einstein deduced his famous Theory of Relativity, E = mc2.
He proved that matter and energy are related. That is:
If matter is destroyed, energy is created
If energy is destroyed, matter is created

19. Nonrenewable Resources
These are substances that are used faster than they are formed.
They include fossil fuels, which form over millions of years from the remains of prehistoric plants and animals.
When burned, these substances release CO2, which threatens to warm our planet

20. Renewable Resources
These are substances that are replaced faster than they are used.
These include solar, hydroelectric, wind, geothermal, and biomass.