Magnetism Slide 2 What is magnetism? Magnetism is the force of attraction between magnets and magnetic objects. Slide 3 Characteristics of Magnets All magnets have a North and a South Pole. All magnets have a magnetic field around them. The magnetic field is a line of force running from the north-seeking pole to the south-seeking pole of the magnet. Slide 4 Earths Poles In our planet we have the North and South Poles. Earth acts like a giant magnet and is surrounded by a magnetic field. Earths magnetic field is what causes the needle of a compass to point in different directions and causes the poles of a magnet to point either North or South. Slide 5 Attractive Magnets!!! The north and south poles of two magnets attract each other. They always need to be opposite poles to be attracted. The magnetic force pulls them together. Slide 6 Magnets of the same pole will repel each other, either two north or two south poles. Slide 7 Magnets and electricity Magnetic fields can be created with batteries, bolts and wire. Slide 8 Magnets and Electricity Electricity and magnetism are related: An electric current produces a magnetic field. A change in a magnetic field can produce an electric current. Slide 9 Magnets and Electricity The strength of an electromagnet can be increased by: Increasing the number of coils. Increasing the voltage of the current. Slide 10 Magnets and Electricity Electromagnets are used in every day life: In telephones, electric motors, generators, televisions, door bells. You can see a huge electromagnet in action in a junkyard. A crane holding the electromagnet can be used to pick up metal pieces when current flows through it. When the crane operator wants to drop the scrap, he or she will simply shut off the current to the electromagnet. Slide 11 Slide 12 How many poles do magnets have? Slide 13 What happens when two magnets of different poles are put close together? Slide 14 What happens when two magnets with same poles are put close together? Slide 15 What is the area of a magnetic force called? Slide 16 Electric current creates a _____________ field. magnetic Slide 17 What do you make if you put together a closed circuit and wrap the wire around an iron bolt? Electromagnet Slide 18 How can you make an electromagnet stronger? You can wrap the wire around the iron bolt more times.