1. Chapter 18 Physics A First Course Electricity and Magnetism

2. Electricity and Magnetism Fields and Forces 18.1 Fields and Forces 18.2 Gravity 18.3 The Electric Field

3. 18A Investigation: The Magnetic Field Key Question: Does magnetic force spread out in a the area around a permanent magnet? *Students read text section 18.1 AFTER Investigation 18A

4. 18A Investigation Topics Use a compass to map a magnetic field. Map out an electric field. Map out a gravitational field.

5. Chapter 18.1 Objectives and Vocabulary field intensity inverse square law Propose a general explanation for how forces act over a distance. Describe why the strength of a field decreases with distance from the source. Describe how fast a force moves between objects.

6. Sound Intensity vs. Distance

7. Fields and Energy

8. Unit Inverse Square Law Light intensity (brightness) decreases by 1/4th as the distance from the source is doubled because the same amount of light energy is dispersed over a greater area (4 times greater).

9. Chapter 18.2 Objectives and Vocabulary gravitational field force field Describe how gravity acts between objects through a field. Calculate the gravitational field on other planets.

11. 18B Investigation: Using Fields Key Question: What does a field tell you about what created it? *Students read text section 18.3 AFTER Investigation 18B

12. 18B Investigation Topics Use a compass to map the magnetic field of a hidden magnet. Use magnetic field map to find the location of a hidden magnet. Use magnetic field map to find the orientation of a hidden magnet.

13. Chapter 18.3 Objectives and Vocabulary electric field source charge shielding Describe how the electric charges act in an electric field. Calculate electric field strength.