Electricity and Magnets

1
Electricity and Magnets

• Topic 4 Physical Science
• Pages 328-337

2

• Television and stereo speakers couldnt work
  without magnets.

Electricity and Magnetism
3
How Are a Compass and a Magnet Alike?
4
Attract and Repel
5
(No Transcript)
6
(No Transcript)
7
Why Do a Hanging Magnet and Compass Turn?

• Earth itself is a magnet. Like a huge bar magnet
  running along Earths center, this magnet would
  create a region of magnetic force called a

MAGNETIC FIELD.
8
Lines of Force
9
Where Do Magnets Come From?

• About 2,000 years ago, people from an area called
  Magnesia found rocks that would attract small
  pieces of iron. The rocks are called
• They contain magnetized iron.
• When the particles are all lined
• up in the same direction, their
• magnetic fields act together.

MAGNETITE.
10

• Magnets can also be created using electric
  current. When an
• electric current flows a magnetic field forms
• around the wire.

11

• You can make a stronger magnetic field by winding
  a wire in loops around an iron bar. When
  electric current flows this creates a temporary
  magnet called an

ELECTROMAGNET.
12
Electromagnets
13
How Are Electromagnets Used?

• A junkyard crane uses a powerful electromagnet.
  Doctors use electromagnets to take iron splinters
  out of patients skin. Recyclers use them to
  separate scrap metals. Electromagnets are also
  used in machines such as tape players, bells,
  motors, buzzers, loudspeakers, and televisions.

14
How Does a Doorbell Work?

• An electric doorbell is made up of an
  electromagnet and a power source.

15
(No Transcript)
16
How Can You Put Electricity to Work?

• Electric motors transform electrical energy into
  movement, or
• This energy can power video recorders, some
  appliances, and other devices.

MECHANICAL ENERGY.
17
Build Your Own Motor

• The following website offers directions for
  building your own motor!

http//fly.hiwaay.net/palmer/motor.html
18
Additional Webquest

• The following webquest link is a great
  opportunity to further your learning!
• http//share1.esd105.wednet.edu/blackl/webquest.ht
  m