MagnetismMagnetism

What is magnetism?What is magnetism?

Magnetism is the force of attraction Magnetism is the force of attraction between magnets and magnetic between magnets and magnetic objects.objects.

Characteristics of MagnetsCharacteristics of Magnets

All magnets have a All magnets have a North and a South North and a South Pole.Pole.

All magnets have a All magnets have a magnetic fieldmagnetic field around around them.them. The The magnetic fieldmagnetic field is a is a

line of force running line of force running from the north-seeking from the north-seeking pole to the south-pole to the south-seeking pole of the seeking pole of the magnet.magnet.

Earth’s PolesEarth’s Poles

In our planet we have the North and In our planet we have the North and South Poles.South Poles.

Earth acts like a Earth acts like a giant magnetgiant magnet and is and is surrounded by a surrounded by a magnetic fieldmagnetic field..

Earth’s Earth’s magnetic fieldmagnetic field is what causes the is what causes the needle of a compass to point in different needle of a compass to point in different directions and causes the poles of a directions and causes the poles of a magnet to point either North or South.magnet to point either North or South.

Attractive Magnets!!!Attractive Magnets!!!

The north and south poles of two The north and south poles of two magnets attract each other. They magnets attract each other. They always need to be opposite poles to always need to be opposite poles to be attracted.be attracted.

The magnetic force pulls them The magnetic force pulls them together.together.

Magnets of the same pole will repel Magnets of the same pole will repel each other, either two north or two each other, either two north or two south poles.south poles.

Magnets and electricityMagnets and electricity

Magnetic fields can be created with Magnetic fields can be created with batteries, bolts and wire.batteries, bolts and wire.

Magnets and ElectricityMagnets and Electricity

Electricity and magnetism are Electricity and magnetism are related:related:

1.1. An electric current produces a An electric current produces a magnetic field.magnetic field.

2.2. A change in a magnetic field can A change in a magnetic field can produce an electric current.produce an electric current.

Magnets and ElectricityMagnets and Electricity

The strength of an electromagnet The strength of an electromagnet can be increased by:can be increased by:

1.1. Increasing the number of coils.Increasing the number of coils.

2.2. Increasing the voltage of the Increasing the voltage of the current.current.

Magnets and ElectricityMagnets and Electricity Electromagnets are used in every day life:Electromagnets are used in every day life:

1.1. In telephones, electric motors, generators, In telephones, electric motors, generators, televisions, door bells.televisions, door bells.

2.2. You can see a huge electromagnet in action in a You can see a huge electromagnet in action in a junkyard. A crane holding the electromagnet junkyard. A crane holding the electromagnet can be used to pick up metal pieces when can be used to pick up metal pieces when current flows through it. When the crane current flows through it. When the crane operator wants to drop the scrap, he or she will operator wants to drop the scrap, he or she will simply shut off the current to the simply shut off the current to the electromagnetelectromagnet..

How many poles do magnets have?

What happens when two magnets of different poles are put close together?

What happens when two magnets with same poles are put close together?

What is the area of a magnetic force called?

Electric current creates a _____________ field.magnetic

What do you make if you put together a closed circuit and wrap the wire around an iron bolt?

Electromagnet

How can you make an electromagnet stronger?

You can wrap the wire around the iron bolt more times.