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

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

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

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

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

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.

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

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

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

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

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

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.

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.

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.

End of Section: Energy Transformations and Conservation

Formation of Fossil Fuels See Figure 18 p. 464-5 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

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

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

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

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.

End of Section: Energy and Fossil Fuels

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

End of Section: Graphic Organizer