Hobbies And Interests
Electromagnets
Any piece of metal coil will become magnetic if you send an electric current through it. For example, an iron nail wrapped in electric wire will turn into an electromagnet if you send a current through the wire. You can increase the magnetic power of an electromagnet by increasing either the voltage of the electric current or the number of coils in the device. In the case of a homemade electromagnet with an iron nail for a core, the iron actually increases the strength of the magnet as well. However, the iron can be magnetized by the electricity, remaining magnetic even if you turn the current off. It would then be a permanent magnet rather than an electromagnet.
Magnetic Poles
If you make an electromagnet at home out of an iron nail wrapped in electric wire, one end of the nail will be its north pole and the other end its south pole. This is an opposite pole electromagnet. If you place the north pole end of an electromagnet near the north pole end of another electromagnet, the two magnets will push each other away. On the other hand, if you place the north pole of one electromagnet next to the south pole of another, they will be drawn together. When it comes to magnets, opposite poles attract each other and like poles repel each other.
Finding the Poles
To find the poles on an electromagnet, you can turn on the electric current and point your magnet at a compass. The compass needle will respond to your device's magnetic field. If the end that is pointing at the compass is the north pole, your compass needle will turn toward it. If the end that is aimed at the compass is the south pole, the compass needle will turn away from it. The same experiment can be done with the other end of the nail to verify that it is really the opposite pole.
Uses of Electromagnets
Because electromagnets can be turned on and off, they can be very useful for moving scrap metal. An electromagnetic crane can pick up the metal and move it, then drop it in a new spot by shutting the current off. Electromagnets can also be used in surgery, to safely remove pieces of metal from the body of an injured patient. Electromagnets can be used to operate door locks remotely with the touch of a button. Maglev trains use the repulsion effect of electromagnets to hover above the train track.