Download Chapter 18: Fields and Forces

Physics A First Course
Electricity and Magnetism
Chapter 18
Electricity and Magnetism
Fields and Forces
 18.1
Fields and Forces
 18.2
Gravity
 18.3
The Electric Field
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
18A Investigation Topics

Use a compass to map a magnetic field.

Map out an electric field.

Map out a gravitational field.
Chapter 18.1 Objectives and Vocabulary

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.



field
intensity
inverse square law
Sound Intensity vs. Distance
Fields and Energy
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).
Unit
Chapter 18.2 Objectives and Vocabulary


Describe how gravity acts
between objects through a
field.
Calculate the gravitational
field on other planets.


gravitational field
force field
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
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.
Chapter 18.3 Objectives and Vocabulary


Describe how the electric
charges act in an electric field.
Calculate electric field strength.



electric field
source charge
shielding