1. 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

2. The time rate of doing work
Energy
The abiltiy to do work
Power
The time rate of doing work
How fast work is done
Power = Work
Time

3. Kinetic Energy = ½ mass x velocity2
- What Is Energy?
Kinetic Energy = ½ mass x velocity2
Kinetic energy increases as mass and velocity increases.

4. Potential Energy = weight x height
- What Is Energy?
Potential Energy = weight x height
Gravitational potential energy increases as weight and height increase.

5. Law of Conservation of Energy
Energy cannot be created or destroyed Example

6. 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.

7. 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

8. 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

9. 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

10. Forms of Energy
Thermal Energy
Electrical Energy
Chemical Energy
Nuclear Energy
Electromagnetic Energy

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

12. Transformations Between Potential and Kinetic Energy
- Energy Transformations and Conservation
Transformations Between Potential and Kinetic Energy
A pendulum continuously transforms energy from kinetic to potential energy and back.

13. Energy Transformations Activity
- Energy Transformations and Conservation
Energy Transformations Activity
Click the Active Art button to open a browser window and access Active Art about energy transformations.

14. 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.

15. End of Section: Energy Transformations and Conservation

16. Formation of Fossil Fuels
See Figure 18 p
Nuclear energy is transformed to electromagnetic energy
Plants and animals transform electromagnetic energy to chemical energy
Coal and oil are formed from ancient plants
Power plants produce steam to turn turbines
Turbines spin to produce electricity
Electricity is sinto thermal and mechanical energy

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

18. 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

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

20. 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.

21. End of Section: Energy and Fossil Fuels

22. 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

23. End of Section: Graphic Organizer