Magnetism

1. Magnetism Section 8.1

2. Magnetism • Magnetism- the properties and interactions of magnets • Interaction between two magnets, called magnetic force, increases as magnets move closer together. • A magnetic field which exerts the magnetic force, surrounds a magnet, and is strongest closest to the magnet.

3. Magnetic Field • http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/elemag.html#c1 • http://www.school-for-champions.com/science/magnetism.htm

4. Magnetism • Magnetic poles – the regions of a magnet where the magnetic force exerted by the magnet is strongest • All magnets have a north pole and a south pole. • Named for the poles of the earth • “north” end of magnet points north • “south” end of magnet points south

5. Magnetism • Like poles repel, unlike poles attract. • Earth has magnetic poles • A compass needle is a small bar magnet that can freely Rotate • A compass need always points north • Magnetic materials- iron, cobalt, and nickel • The magnetic field created by each atom exerts a force on nearby atoms

6. Magnetic Domains • Magnetic domains- groups of atoms with aligned magnetic poles • In a magnet, the like poles of all the domains point in the same direction • Temporary magnets are made by placing a magnetic material in a strong magnetic field, forcing a large number of magnetic domains to line up

7. Cutting a bar magnet