Magnets Introduction Magnets have been known for centuries

Magnets

Introduction • Magnets have been known for centuries. • The Chinese and Greeks knew about the “magical” properties of magnets. The ancient Greeks used a stone substance called “magnetite. ” They discovered that the stone always pointed in the same direction. Later, stones of magnetite called “lodestones” were used in navigation.

What is Magnetism? • Magnetism is the force that causes a nail or paper clip to be pulled toward a magnet. Play around with a magnet and you'll quickly see magnetism in action!

Continued • A magnet has two ends called magnetic poles or just poles for short. • A magnet’s pull is strongest at the poles. • Poles are usually marked North and South.

Continued William Gilbert, an English physician, first proposed in 1600 that the earth itself is a magnet, and he predicted that the Earth would be found to have magnetic poles.

Continued • The ends of a magnet are where the magnetic effect is the • strongest. These are called “poles. ” Each magnet has • 2 poles – 1 north, 1 south.

A paperclip is attracted to the ends of a bar magnet • The magnet also is pulled towards the paperclip. The two forces are the same size and in opposite directions.

Ends Of Magnets A magnet has a north pole and a south pole. S N

The north pole attracts the south pole of the other magnet. S N S N N

The north pole repels the north pole of the other magnet. S N N • You can feel the magnets pushing apart. • This is called repulsion Note - south poles also repel each other S