Download Magnets and Magnetism

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