Electricity and Magnetism -- Electromagnetism

Does an electrical current affect a compass?

Assemble these materials:

two battery holders and batteries *

a compass *

a wire with alligator clip ends *

tape

1. Determine which way is north, using a compass, and tape a wire with alligator clip-ends so that a few centimeters in the middle are pointing nearly north-south. Place the compass on top of the wire.

Now connect one clip to one end of a battery (using a battery holder), and then touch the other end of the wire to the other end of the battery. Notice what happens to the compass as you connect and disconnect the circuit.
Reverse the battery, so that the current goes the other way. Is the reaction of the compass different?
Reorient the wire, so that now it is running east-west. Now what happens when you start and stop the current?

These experiments were first done by H. C. Oersted in 1819. It was the first time anyone had realized that there is a connection between electricity and magnetism, and led to the invention of the electrical motor.