1. Energy: Forms and Changes

2. Forms of Energy Thermal(Heat) Electrical Chemical Sound
The main forms of energy are:
Thermal(Heat)
Electrical
Chemical
Sound
Light-Electromagnetic
Nuclear
Mechanical

3. Energy Transformations or Conversions
Most forms of energy can be transformed into other forms.
A change from one form of energy to another is called an energy transformation.

4. Transformations Between Potential and Kinetic Energy
One of the most common energy transformations is the transformation between potential energy and kinetic energy.
In waterfalls such as Niagara Falls, potential energy is transformed to kinetic energy.
The water at the top of the falls has gravitational potential energy.
As the water plunges, its velocity increases.
Its potential energy becomes kinetic energy.

5. Kinetic-Potential Energy Conversion
Roller coasters work because of the energy that is built into the system. Initially, the cars are pulled mechanically up the tallest hill, giving them a great deal of potential energy. From that point, the conversion between potential and kinetic energy powers the cars throughout the entire ride.

6. Kinetic vs. Potential Energy
At the point of maximum potential energy, the car has minimum kinetic energy.

7. Mechanical Energy Mechanical energy is the combination of:
Potential & Kinetic Energy
Examples: The ride on a roller coaster, a juggler.

8. Thermal Energy
All the kinetic Energy due to random motion of the particles make up the thermal energy of an object.
The faster the particles move the higher the temperature.
The major determining factor that determines thermal energy is the number of particles. The more particles you have the greater the thermal energy.

9. Electrical Energy
The energy of moving electrons.

10. Sound Energy
Sound energy is caused by the vibration of objects, such as gasses, liquids, solids.

11. Light energy
The vibration of electrically charged particles.

12. Nuclear Energy
Energy that comes from changes to the nucleus of an atom.
Nuclear fusion: The joining together of two nucleus’ in a process called nuclear fusion.
Nuclear fission: the splitting part of the nucleus of an atom.

13. Chemical Energy
Comes from chemical reactions

14. Common Energy Transformations Every day, energy transformations are all around you. Some of these transformations happen inside you!

18. Energy and Friction
So what happens to the energy of the top?
As the top spins, it encounters friction with the floor and friction from the air.
Whenever a moving object experiences friction, some of its kinetic energy is transformed into thermal energy. (Why you cannot have perpetual motion machines)
So, the mechanical energy of the spinning top is transformed to thermal energy.
The top slows and eventually falls on its side, but its energy is not destroyed—it is transformed.

19. Conservation of Energy
If you set a spinning top in motion, will the top remain in motion forever?
No, it will not.
Then what happens to its energy?
Is the energy destroyed?
Again, the answer is no.
The law of conservation of energy states: Energy is not created nor destroyed only changed into other forms. The total amount of energy remains the same.

20. What happens when electrical energy is changed to thermal energy?
a. An energy transfer takes place.
b. A force change takes place.
c. An energy conversion takes place.
d. An electrical conversion takes place.

21. What happens when electrical energy is changed to thermal energy?
a. An energy transfer takes place.
b. A force change takes place.
c. An energy conversion takes place.
d. An electrical conversion takes place.

22. Any time an energy conversion takes place, some of the original energy is converted to which one of the following?
a. sound energy
b. potential energy
c. light energy
d. thermal energy

23. Any time an energy conversion takes place, some of the original energy is converted to which one of the following?
a. sound energy
b. potential energy
c. light energy
d. thermal energy

24. a. thermal energy c. electrical energy
When you eat fruits and vegetables, which of the following types of energy are you taking in?
a. thermal energy c. electrical energy
b. sound energy d. chemical energy

25. a. thermal energy c. electrical energy
When you eat fruits and vegetables, which of the following types of energy are you taking in?
a. thermal energy c. electrical energy
b. sound energy d. chemical energy

26. Which of the following is a conversion from light energy to chemical energy?
a. turning on a stove to heat dinner
b. turning on a lamp
c. growing an apple tree
d. making toast in a toaster

27. Which of the following is a conversion from light energy to chemical energy?
a. turning on a stove to heat dinner
b. turning on a lamp
c. growing an apple tree
d. making toast in a toaster