by Earl King

Created on: June 25, 2008

HOW ELECTRICAL CURRENT FLOWS

Throw a switch on the wall and light will flood the room. Click the power button on your TV remote and sound and pictures appear. Electricity controls your heating and air conditioning as well as the rest of your world.

How does it work? How does it get to your light? Notice some things right off about electrical current flow. It's fast, nearly instantaneous. Also, the current that began flowing the moment you closed that switch was just produced by the generator of the power station perhaps hundreds of miles away. Electricity cannot be stored; it must be generated as needed.

Electric current is the flow of negatively charged particles called electrons. To understand this, examine how the material world is made. This line of thought began several thousand years ago. Most of the inventive or development progress on the makeup of matter is from the last 150 to 200 years. Matter was thought to be made up of many, many small particles called atoms.

We cannot see the structures of atoms very well. However indirect measurements are made to give some information. Physicists use their imagination to develop models to represent the unknown. Then using measurements and theories the models are modified until they can explain a varity of physical phenomena without contradicting itself. John Dalton started it with his atomic theory and Ernst Rutherford furthered it with his nuclear atom. The resulting model is a small solar system. The sun is the atomic nucleus which contains neutrons with no charge and positively charged protons. Surrounding this sun are planets representing negatively charged electrons in various orbits.

Some atoms like hydrogen have only one electron and others have many orbital electrons. There are enough electrons in orbit to balance the positive charge of the nucleus and leave the atom electrically neutral.

Copper atoms are bound in a crystalline lattice. The outer orbits of these atoms contain electrons not strongly attached. These free electrons, as they are called roam about at random in the lattice.

If a copper wire was attached to the negative pole and the positive pole of a battery, we would find that when a switch was closed an electrical stress was placed across the wire. The free electrons would begin to drift toward the positive pole (opposites attract) where there was already a deficiency of electrons. The excess of electrons at the negative pole of the battery would begin to move into the wire, contributing

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