for 9th grade physics, chapter 6 "energy transformations and energy transfers"

What is Energy?

What are the different forms of Energy?

What is Energy?

•The ability to do work

Can you make things move?

•Then you have energy…

•…but there are seven different kinds of energy…

1. Heat Energy

•The random motion, or vibration, of atoms in matter

•The faster the atoms vibrate the more heat energy they have

2. Chemical Energy

•What holds atoms in molecules together

•Can be released by chemical reactions like burning wood

3. Electrical Energy

•The movement of electrons through matter

•Electricity is a form of electrical energy

4. Light Energy

•The energy carried by light

•Yes, whenever you are looking at light, you are looking at energy

5. Mechanical Energy

•The energy of moving things

•When you ride a bike you use mechanical energy

6. Nuclear Energy

•Holds protons and neutrons together in an atom’s nucleus

•Powers the sun and nuclear power plants (reactors)

7. Sound Energy

•Vibrates air molecules•The air molecules move tiny bones in your ear

•The message of sound then moves to your brain

•Can also vibrate objects

The Law of Conservation of Energy:

So energy is always conserved, it is never "lost" or "wasted“.

Energy can change form, but can’t be created nor destroyed.

Chemical energy in gasoline is changed to heat energy and then to mechanical energy in a car.

Mechanical energy to sound energy and some lost thermal energy

Kinetic energy to electrical energy

Chemical energy stored in explosives is transferred to the surroundings as thermal energy, sound energy and kinetic energy.

Chemical energy to potential energy and kinetic energy

Electrical energy to sound energy and some lost thermal energy

The battery transfers stored chemical energy as electrical energy. The electrical energy is transferred to the surroundings by the lamp as light energy and thermal energy (heat energy).

Energy transfer

Nuclear energy to thermal energy