-Review the behavior of magnetic poles and electromagnets -Construct and test a simple motor -Study how magnets can be used to build a generator TODAY’S OUTCOMES: MAGNETISM

Both round and bar magnets have 2 poles (N and S) that behave in the same way toward other N and S poles - ALL magnets have an N and S pole! You can never get an N-pole or an S-pole by itself. If the magnet is broken between its poles, new N and S poles will form at the boundary, and the fragments will attract. This is the most common way bar magnets can break. S N S N S N If the magnet fractures along the direction of its poles, the pole ends remain intact, and the fragments will repel. This is the most common way disc magnets can break. S N S N S N > What happens if a magnet is broken? What happens to a magnet broken in half between its two poles? How will the two fragments behave? What happens to a magnet broken in half along the direction of its poles? How will the two fragments behave? Explain your reasoning.

An iron core makes an electromagnet stronger, because the iron turns into a temporary magnet itself when exposed to a magnetic field. Aluminum is not magnetic, so an aluminum core will not make the magnet stronger. > What effect does wrapping an insulated wire around an iron core have on the strength of an electromagnet, and why? Would using an aluminum core have the same effect? (Try this using the aluminum nail instead of the iron nail.)

-An electric current always produces a magnetic field -The direction and strength of the magnetic field depend on the direction and strength of the current -Wrapping the wire into a coil, where the wires all are in a parallel spiral, increases the strength of the magnetic field KEY POINTS:

-Review the behavior of magnetic poles and electromagnets ✓ -Construct and test a simple motor -Study how magnets can be used to build a generator TODAY’S OUTCOMES: MAGNETISM