Electricity, Magnetism, and Light
James Clerk Maxwell demonstrated that the light is made of electric and magnetic fields that change very rapidly. When you walk across a rug in the winter (and there isn't very much water in the air), you can collect electric charges that make your hair stand on end. You can sometimes give other people shocks by moving these electric charges from you to them (and they can shock you by doing the same).
Your hair stands on end because the electric charges create a "force field" that pushes on other charges. We call that force field an electric field because electrical charges make it.
You are probably also familiar with magnets. If you look closely at a magnet, you will find that it always has two "poles" (refrigerator magnets are flat - with one pole on one side of the magnet and the other pole on the other side - so finding the magnet's poles can be confusing). The Earth is also a magnet - with a North Pole and a South Pole. If we suspend a small magnet so that it is free to turn, one of the magnet's poles will turn until it points north. The magnet turns because the Earth's magnetic field creates a force that pushes the magnet to point north and south.
Maxwell's work showed that electricity and magnetism were connected. His equations showed that if electric charges are pushed or pulled, the changes in the speed of the charge create magnetic fields. In the same way, if magnetic fields change, they can create electric fields. This understanding allowed engineers to create electric generators that have big magnets. The generators create flowing electricity by pushing electric charges in wires with magnetic fields created by the magnets....READ ON...http://eosweb.larc.nasa.gov/EDDOCS/electric.html
Posted by Jay Roberts at 05:13 AM | Permalink