1. Chapter 12

2.  Magnetic Forces  Produce a magnetic field  Similar to an electric field  Act under similar rules  Strength depends on distance  Like poles repel, opposite poles attract  Different from Electric charges  You can not isolate a magnetic pole

3.  What is it?  The space around a magnet ! (easy)  Acts in different ways  The north pole is attracted to the south pole – this creates a magnetic field – why a magnet works  Electrons and magnets  Every spinning electron is a magnet  Therefore every electric current has a magnetic field  Double the amount of spinning electrons double the force of the magnet  Electrons must be spinning in the same direction  Opposite spins cancel each other out

4.  Clusters of aligned atoms  When clusters of atoms line up with each other they make a magnetic domain  Not every piece of iron is magnetic  But they have the ability to be aligned  When you bring a magnet close to a nail the atoms are induced into alignment  Works the same in cobalt and nickel  Softer material is easier to magnetize  Easier for the atoms to line up  The softer the material, the better the magnet  Dropping magnets can make them weaker  Quick changes in motion can move the atoms out of alignment

5.  A single moving charge produces a magnet  That’s your single spinning electron  Any current carrying wire produces a pattern of concentric circles around the wire  Reverse the direction of current, reverse the circle cycle  Electromagnets  When a metal is induced to align its atoms by an electric current  The higher the current the stronger the magnet  What is needed then? (volts, watts, amps, ohms)?

6.  Read pages 197 – 200 (12.5)  Answer Review Questions on p 206 #1-8