Electromagnetic Fields
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Description: This applet simulates the effect of a magnetic field on a metal object (in this case, one of several cars.) 
To try this simulation: To move the magnetic crane, left-click and drag your mouse. To raise or lower the magnet, right-click and drag up or down. To adjust the magnet's power, right-click and drag your mouse left to right. The car will be yellow if it is under the crane's magnet. The car's color will change to green if it is being raised or lowered by the magnet. 
What's Going On? To lift a weight, the electromagnet must attract it with a force greater than the force of gravity. How strong an electromagnet is depends on:
   • the electric current passing through it
   • the number of turns of wire that make up the coil
   • the type of material in its core.
There's More! Electromagnets are common in many of our appliances. Turning on your microwave involves the use of an electromagnet. Your doorbell rings because of electromagnets. Relays and solenoids (which are also electromagnets) in your washing machine switch electrical circuits back and forth - so your spin cycle is dependent on electromagnets. In fact, the washing machine motor itself is an electromagnet!  Junkyards use giant electromagnets hanging on cranes to move huge pieces of metal from place to place.   Even your TV uses electromagnets to scan the picture on the screen.

In theory, much of the matter in the universe is magnetic - that is, able to exert a magnetic force. In practice, substances such as iron make better magnets than others, such as glass or plastic.  Iron and other strongly magnetic materials are used to increase the strength of electromagnets and record information on audio/ video tapes and computer discs. The iron dust shows the magnetic field lines. These represent lines of force. They stretch from one end of the magnet to the other.

The electromagnet is a coil of wire around an iron rod. Whenever electricity flows through a wire a magnetic field is produced.  Electromagnets are used in devices such as computer disk drives, tape recorders, television picture tubes, speakers, and microphones.
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