Magnets have two poles.
There are called North and South.
If you put North and North together they will repel.
If you put South and South together then they will repel.
If you put North and South together then they will attract.
The magnetic field goes from North to South.
When the lines are close together it means that the magnetic field is strong
When the lines are far apart it means that the magnetic field is weak.
1. Label one area where the magnetic field is strong and one area where it is weak.
Electromagnets are magnets that are made from wires that have an
electric current flowing through them.
This makes the wire magnetised.
Without the current the wire will not be magnetic.
To make electromagnets stronger we can do 3 things:
1.Increase the current (don’t have anything else in the circuit)
2.Increase the number of times that the wire is coiled
3.Add a magnetic core (iron works, steel is better)
Use kerboodle page 136-137 to make notes on the following:
1. Maglev trains and how they use electromagnets
The maglev train has two electromagnets: levitation electromagnet and
guidance electromagnet
Levitation electromagnet is very powerful which help the train to float.
There is no friction between the train and the rail, so the train moves
faster.
Guidance electromagnet pushes the train to move forward
Use kerboodle page 136-137 to make notes on the following:
2. How X-rays use electromagnets in the form of a relay
Relay uses a small current circuit to switch on and off a bigger current circuit.
When small circuit is switched on, the electromagnetic becomes magnetized. It
makes two metal pieces to attract. Bigger circuit is completed and switched on.
X-ray machine turn on
Use kerboodle page 136-137 to make notes on the following:
3. Using an electromagnetic switch to start a car
Car needs a big current in order to start and it could be dangerous
Electromagnet can be used to switch on the car and it is safer.
Use kerboodle page 136-137 to make notes on the following:
4. How scrap car garages use an electromagnet to move cars and to separate
different metals
Electromagnet is attached to a crane. When we switch on electromagnet, the
car is attracted and stuck to the crane. Then we can move the car away.
Metals such as iron and steel are attracted to electromagnet while aluminium
and copper aren’t.
Electromagnet is used to sort metals in these groups
Use kerboodle page 136-137 to make notes on the following:
5. Electromagnets in a motor such as those used in a microwave
There is a coil in the microwave
When turning on, the current flows into the coil, the coil becomes an
electromagnet.
The force between the coil and a permanent magnet causes the coil to spin