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://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