Download Magnetic? - Mrs. burt`s physical science class

Physical Science
Unit 8:
Lesson 6: Magnetism
Lesson 7: Electricity and
Magnetism
Lesson 8: Lab: Motoring On!
Lesson 6
• I can explain a diagram
that shows the lines of
force in a magnetic
field.
• I can Identify materials
that are magnetic.
• I can compare a
magnetic field with an
electric field.
Magnetism
Magnets behave in predictable ways.
Repulsion
Attraction
Click and Drag
Bar Magnet
Bar magnets are simply pieces of magnetized metal.
What happens when you cut a bar
magnet in half?
An electrically charged particle can
occur with a single positive or
negative charge.
No matter how you cut a magnet, if
it has a south pole, it will have a
north pole.
Magnetic poles always occur in pairs.
Dipolar-An object with two sides that
have opposite characteristics.
If you have 2 bar
magnets, the north pole
of one will attract the
south pole of the other.
Opposites
Attract
Unlike poles attract
one another.
Likes Repel
Like poles repel
one another.
The north pole of
one magnet will
repel the north
pole of another
magnet.
Domains
Domain-A tiny
region in which
adjacent atoms
that have
magnetic fields
line up with
their magnetic
fields oriented
in the same
direction.
How are
magnets
made?
Permanent Magnet
• Bar Magnets
• Made in a factory
• All their magnetic material
is aligned more in one
direction than in others.
• Overall magnetic force is
strong
Temporary Magnet
• Nail
• Contain magnetic domains
• Behave like magnets only
when in the presence of
magnets
• These items alone do not
exert a discernible magnetic
force
Magnetic?
The refrigerator, alligator paper clip, and nail alone do not exert a discernible
magnetic force.
Magnets Exert Force
Magnetic Field
The space around every magnet where the
magnetic force can be felt.
Magnets do not need to touch to exert a force
on another object.
The magnetic field around a magnet is similar to
the electric field around an electric charge.
The magnetic field is shown by the iron fillings
and the lines.
Earth is a Magnet
The Earth behaves like a
giant bar magnet.
Earth’s geographic north
pole is actually close to
its magnetic south pole
Lesson 7:
• I can explain how a magnetic field can be
created by an electric current flowing in a
wire.
• I can describe how different variables
influence the strength of an electromagnet.
Electricity and Magnetism are Related
You can use
moving
electric
charges to
produce a
magnetic
field in the
space
around
them.
You can use a
changing
magnetic
field to
generate an
electric
current.
You can use moving
electric charges to
produce a magnetic
field in the space
around them.
You can use
a changing
magnetic
field to
generate an
electric
current.
A temporary magnet made using
electric current, usually running
around a metal core.
Electromagnet
1. Electricity Source:
2. Metallic Core:
3. Wire:
1. The amount of
electric current.
2. The wire Coil
Galvanometers
Galvanometer-An instrument used to
indicate the presence, direction, or
strength of a small electric current.
The typical galvanometer is a sensitive
laboratory instrument used mainly to
detect and compare currents.
In the galvanometer, the wire is wound
into a coil. When current flows through the
coil, one end of the coil becomes a north
magnetic pole, the other a south magnetic
pole. When a permanent magnet is placed
near the coil, the two fields—the one from
the coil and the one from the magnet—
interact. The like poles will repulse each
other and the unlike poles will attract. The
amount of attraction and repulsion
increases as the strength of the current
increases.
A magnetic field can cause an electric
charge to move.
What happens to the electrons in the
wire when we place the battery next to
it, but do not move it?
What happens when we move the
battery?
Lesson 8: Lab: Motoring On!
Create an electric motor.