1. Magnetism and Electromagnetism

2. Magnets and Electromagnetism Georgia Performance Standards
SPS10. Students will investigate the of properties electricity and magnetism.
c. Investigate applications of magnetism and/or its relationship to the movement of electrical charge as it relates to
electromagnets
simple motors
permanent magnets

3. How were magnets discovered?
Magnetite/Lodestone = naturally occurring mineral
Could pick up metallic objects
If floated on water, it would always orient itself in the same direction

4. The magnetic force… (notes) Is an interaction between two magnets
can even be felt before magnets touch
gets stronger as the magnets get closer

5. What is a magnetic field?
(notes)
a field that
surrounds a magnet and exerts magnetic force
connects the north and south poles of a magnet together

9. How do magnets interact?
(notes)
opposite poles (N,S) attract each other
like poles (N, N or S,S) repel each other

10. Earth is a giant magnet
Earth’s geographic north pole (GNP) is its magnetic south pole (MSP)
the “north” needle on a compass points toward the GNP because it’s really the MSP!

11. What makes something magnetic?
(notes)
magnetic domain = groups of atoms with aligned magnetic poles
-- unaligned magnetic domains = nonmagnetic
-- aligned magnetic domains = magnetic

12. How can magnets be “demagnetized?”
(notes)
How can magnets be “demagnetized?”
heating
jarring
hitting
dropping
both cause the magnetic domains to move around and become unaligned

13. demagnetized magnets can be re-magnetized by exposing them to a very strong magnetic field

14. What happens if you cut a magnet in to 2 pieces?
(notes)
What happens if you cut a magnet in to 2 pieces? S N
break in two S N S N

15. What is an electromagnet?
(notes)
What is an electromagnet?
Temporary magnet
Made by placing a piece of metal inside a current-carrying wire
Temporarily aligns magnetic domains

17. Benefits of Electromagnets (versus Permanent Magnets)
How can the strength of an electromagnet be increased?
1. add more coils of wire
2. increase the electric current through the wire
Benefits of Electromagnets (versus Permanent Magnets)
Turn on and off
Control the strength

18. Examples of Ways Electromagnets are used are…
Look at the following slides and know how each work… especially the relationship between the permanent magnets and electromagnets to make it move (if they have them…)
What are the two main parts of an electric motor? Permanent magnet and electromagnet.

21. galvanometer

22. magnets

24. It is possible to… (notes)
produce an electric current by moving a loop of wire through a magnetic field
This is called ELECTROMAGNETIC INDUCTION.
Main example of Electromagnetic Induction in action is a
generator: produces electricity by rotating a coil of wire in a magnetic field
Other Examples of Uses: Hydroelectric dam, windmill, shake flashlight, winding flashlight