Electromagnet

What is electromagnet ?
Electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current.
The magnetic field disappears when the current is turned off.Electromagnets are widely used as components of other electrical devices, such as motors, generators, relays, loudspeaker, hard disk, MRI machines, scientific instruments, and magnetic separation equipment.
History
Danish scientist Hans Christian Orsted  discovered in 1820 that electric currents create magnetic fields.British scientist William Sturgeon invented the electromagnet in 1824, his first electromagnet was a horseshoe-shaped piece of iron that was wrapped with about 18 turns of bare copper wire it from the windings.
                                                                  
How to make an electromagnet: 
You will need:

• A large iron nail (about 3 inches)
• About 3 feet of THIN COATED copper wire
• A fresh D size battery
• Some paper clips or other small magnetic objects
  What to do :
  • 1. Leave about 8 inches of wire loose at one end and wrap most of the rest of the wire around the nail. Try not to overlap the wires.
    
  • 2. Cut the wire (if needed) so that there is about another 8 inches loose at the other end too.

  • 3. Now remove about an inch of the plastic coating from both ends of the wire and attach the one wire to one end of a battery and the other wire to the other end of the battery. See picture below. (It is best to tape the wires to the battery - be careful though,the wire could get very hot)

   How does it works:
   Most magnets, like the ones on many refrigerators, cannot be turned off, they are called permanent magnets. Magnets like the one you made that can be turned on and off, are called electromagnet. They run on electricity and are only magnetic when the electricity is flowing. The electricity flowing through the wire arranges the molecules in the nail so that they are attracted to certain metals. Never get the wires of the electromagnet near at household outlet! Be safe - have fun!