1. Magnets and Magnetism
Unit 7, Lesson 4

2. What are some properties of magnets?
Magnets- describe any material that attracts iron or objects made of iron.
Magnetic Forces- when you bring 2 magnets together, they exert a push or pull
Only 3 forces can act at a distance…. Magnetic force, gravity, and electric force

3. What are some properties of magnets?
Magnetic Poles- 2 magnets can push each other apart because of their ends (poles)
Opposites attract, like repel
Magnetic Fields- area surrounding a magnet where magnetic forces can be detected
Magnetic field is strongest at the poles

4. What causes magnetism? The Type of Atom The formation of Domains
As electrons moves in an atom, it makes, or induces a magnetic field  this creates a north and south pole
The formation of Domains
Domains are like tiny magnets within an object
When a magnetic material is placed in a magnetic field, most of the domains point toward the same direction
In other objects, there are no domains to line up because the atoms have no magnetic fields  These materials cannot become magnetized.

5. What are some types of magnets?
Ferromagnets
A material that can be turned into a magnet….and can be a permanent magnet when placed into a strong magnetic field
Can be various shapes (bar, horseshoe, etc.)
Electromagnets
Very strong magnet made by iron core wrapped with electrical wire. When an electric current is in the wire (when it is turned on), a magnetic field forms
The strength of the magnet depends on the strength of the current

6. Types of magnets… Temporary magnets
Some materials can be made into a temporary magnet when magnetizing the object. The domains line up when placed in a strong magnetic field. (EX: magnetizing the needles)

7. Demagnetizing a Magnet
A magnet is no longer a magnet
The domains are not lined up anymore
Ways to Demagnetize a Magnet
1) Heating
2) Dropping
3) Other Strong Impact

8. How is Earth like a giant magnet?
Earth is like a giant magnet
The inner core is made of solid metal
The outer core is made of liquid iron and nickel
As Earth rotates, the outer liquid core moves the charged particles around and create the magnetic field

9. What is an aurora? The sun ejects charged particles
When the particles reach Earth, they are guided by the magnetic field
They enter the atmosphere at the poles (where it is the strongest attraction)
From there, the particles mix with atoms in the air causing atoms to emit the visible light