2. Exponents - What Is Energy?
An exponent tells how many times a number is used as a factor. For example, 3 X 3 can be written as 32. You read this number as “three squared.” An exponent of 2 indicates that the number 3 is used as a factor two times. To find the value of a squared number, multiply the number by itself.
32 = 3 X 3 = 9
Practice Problem
What is the value of the number 82? 64

3. The ability to do work or cause a change is called Energy.
- What Is Energy?
Kinetic Energy
The ability to do work or cause a change is called Energy.
Kinetic energy is the energy of motion.
It increases as mass and velocity increases.

4. Gravitational potential energy is equal to weight times height.
- What Is Energy?
Gravitational potential energy is equal to weight times height.
It is sometime referred to as energy of position.

5. Elastic Potential Energy: comes from material snapping back from Compression or Stretching. Elastic Potential Energy will be converted to Kinetic, Acoustic and Thermal energy when it is released.

6. Using Prior Knowledge - What Is Energy?
Before you read, look at the section headings and visuals to see what this section is about. Then write what you know about energy in a graphic organizer like the one below. As you read, write what you learn.
What You Know
The joule is the unit of work.
Energy has different forms.
What You Learned
Power is the rate at which energy is transferred.
The two basic kinds of energy are potential energy and kinetic energy.

7. Calculating Mechanical Energy
- Forms of Energy
Calculating Mechanical Energy
The kinetic energy of a 500-N diver during a dive from a 10-m platform was measured. These data are shown in the graph.

8. Calculating Mechanical Energy
- Forms of Energy
Calculating Mechanical Energy
Reading Graphs:
According to the graph, how much kinetic energy does the diver have at 8 m?
About 1000 J

9. Calculating Mechanical Energy
- Forms of Energy
Calculating Mechanical Energy
Calculating:
Using the graph, find the kinetic energy of the diver at 6 m. Then calculate the diver’s potential energy at that point.
Kinetic energy = about 2000 J; potential energy = about 3000 J

10. Calculating Mechanical Energy
- Forms of Energy
Calculating Mechanical Energy
Inferring:
The mechanical energy of the diver is the same at every height. What is the mechanical energy of the diver?
About 5000 J

15. Thermal energy: Is the heat energy from vibrating molecules
Forms of energy
Thermal energy: Is the heat energy from vibrating molecules
Electrical energy: Is the flow of electrons .
Chemical energy: Is released when old chemical bonds are broken
Nuclear energy: Is the energy released as matter is converted to other forms of energy

16. Forms of energy
Electromagnetic Energy: is light energy. It is carried by waves of photons. Photons are given off and received by electrons. Includes all the wavelengths of light from Radiowaves to Visible Light to Gamma Rays.
Mechanical Energy: is the combination of kinetic and Gravitational Potential. Usually found in projectiles.

17. End of Section: Forms of Energy

18. Energy Transformations
- Energy Transformations and Conservation
Energy Transformations
Most forms of energy can be transformed into other forms.

19. Transformations Between Potential and Kinetic Energy
- Energy Transformations and Conservation
A pendulum continuously transforms energy from kinetic to gravitational potential energy and back.
Transformations Between Potential and Kinetic Energy
Harvard Video

20. Asking Questions - Energy Transformations and Conservation
Before you read, preview the red headings. In a graphic organizer like the one below, ask a question for each heading. As you read, write answers to your questions.
Question
Answer
What is an energy transformation?
An energy transformation is a change from one form of energy to another.
What are some examples of transformations between potential and kinetic energy?
Juggling and pendulums show transformations between potential and kinetic energy.
What is conservation of energy?
The law of conservation of energy states that energy cannot be created or destroyed.

21. A pendulum’s period of swing is determined by gravity and length of swinging object (ONLY)

22. Use of Fossil Fuels - Energy and Fossil Fuels
Fossil fuels can be burned to release the chemical energy stored millions of years ago.

23. Previewing Visuals - Energy and Fossil Fuels
When you preview, you look ahead at the material to be read. Preview Figure 18. Then write two questions that you have about the diagram in a graphic organizer like the one below. As you read, answer your questions.
Using Fossil Fuel Energy
Q. What energy transformation occurs in the sun?
A. Nuclear energy to thermal energy and electromagnetic energy
Q. What energy transformation takes place when coal is burned?
A. Chemical energy to thermal energy

24. Links on Energy Transformations
- Energy and Fossil Fuels
Links on Energy Transformations
Click the SciLinks button for links on energy transformations.

25. Click the Video button to watch a movie about the use of fossil fuels.
- Energy and Fossil Fuels
Use of Fossil Fuels
Click the Video button to watch a movie about the use of fossil fuels.

26. End of Section: Energy and Fossil Fuels

27. Graphic Organizer Energy Kinetic energy Potential energy Joules Work
is the ability to do
exists as
measured in
Kinetic energy
Potential energy
Joules
Work
which at a given rate is
can be
Elastic
Gravitational
Power

28. End of Section: Graphic Organizer