Electromagnetism

While preparing for an evening lecture on 21 April 1820, Hans Christian Orsted made a surprising observation. As he was setting up his materials, he noticed a compass needle deflected away from magnetic north when the electric current from the battery he was using was switched on and off. This deflection convinced him that magnetic fields radiate from all sides of a wire carrying an electric current, just as light and heat do, and that it confirmed a direct relationship between electricity and magnetism. This is where the electromagnetism born.( Source : Wikipedia)

Electromagnet can be easily made by take a long wire and make a coil around the nail. Then connect the both end of wire to positive terminal and negative terminal to the battery. Now you got a electromagnet.

When the current flow through the coil of wire it produce a magnetic field around. The positive terminal will be north pole and negative terminal will be south pole. If the both terminal connect in opposite direction the the negative will be north pole and positive will be south pole.

The magnetic field will be create along the coil will be like in this picture below.

This is not a permanent magnet. The magnetic field will be weaker due to the power loss of the battery. so it's called temporary magnet.

NOW YOU CAN MAKE ONE TEMPORARY MAGNET TO PLAY WITH YOUR

LITTLE CHILDREN