Download Electricity and Magnetism

Chapter 15,
Lesson 2
HOW ARE ELECTRICITY
AND MAGNETISM
RELATED?
What is magnet?
Magnet is an object that attracts iron
and a few other metals.
Magnets attract steel because it
contains iron.
There are different shapes of magnets:
Some are like bars, some are U-shaped,
some are thin and flat.
ARE THESE ITEMS MAGNETIC OR NOT?
OUT OF THE FEW ITEMS BELOW, CAN YOU PLACE
THE CORRECT BOX
.
Magnetic
Nonmagnetic
THE ITEMS IN
If you grouped these objects this way,
then you are correct.
Magnetic
Nonmagnetic
Nonmanetic
Magnet:
Distance affects the strength
of magnet’s attraction.
Magnets differ in size, shape,
strength, and uses.
Magnets have two ends or poles, called magnetic
poles. One end will point north (N), and the other
will point south (S).
Unlike (Opposite) poles of magnets attract each
other while like poles of magnets repel.
The space around a magnet in which the force
of the magnet acts is called magnetic field.
The force of the magnet is more in the poles
than in the middle of the magnet.
Electromagnets:
When an electric current passes through a wire,
a magnetic field is formed around the wire.
What is an electromagnet?
When an electric current is passed through a coil of wire
wrapped around a metal core, a very strong magnetic
field is produced. This is called an electromagnet.
We have seen how electricity can produce a magnetic
field, but
Can a magnetic field also produce electricity!
Explain how?
Moving a loop of wire through a magnetic field produces
an electric current.
A generator is a device used to produce
electric.
If you turn a coil of wire in
a magnetic field, electricity
is produced.
What are electric motors?
An electric motor is a device which changes electrical
energy into energy of motion “mechanical energy”.
OTHER
USES OF MAGNETS:
The edge of the
refrigerator door is lined
with a magnet. It holds
the door to the metal
frame.
Compasses help people use
the earths magnetic force to
find their way.
Credit cards. The thin, black
bar on the back is coated
with tiny magnets. It holds
information.
Floppy disks are made of
plastic and coated in magnetic
particles. Floppy disks are used
to save and retrieve
information.
Doorbells use magnets
too. The magnet pulls the
hammer forward to strike
the bell.
There are tiny magnets inside a
stereo, telephone, vacuum
cleaner and washing machine.