ELECTRICITY VOLUME ONE

Adam writes...

So Jim, for superstition's sake I'm going to lay off the baseball questions for now.

So tell me the deal with this, Jim. If you look at the different milestones going back down the communication technology curve, you'll see computers, then TV, then radio, then telephones, telegrams, and finally singing telegrams. All of these advances (plus light bulbs, home appliances, and heavy metal music) are made possible by electricity.

What IS electricity? The flow of charged particles? Is that right? Are there different types of electricity? How and when did we realize electricity exists, and how and when did we learn how to use it?

Now Jim, I know that's a lot to ask of a busy man like yourself. Perhaps you could answer in several different posts rather than one uber-post.


That is a lot of question and it does seem appropriate to answer on the installment plan. For the first part, let's answer "What IS electricity? The flow of charged particles? Is that right? Are there different types of electricity?"

Electricity is free electrons, and there is only one type of electricity. To understand electricity, we have to go back to our chemistry lessons and look at elements and atoms. As I'm sure you know, atoms contain a nucleus made up of positively charged protons and neutrally charged neutrons. Orbiting around the nucleus are negatively charged electrons. These orbits are more accurately called shells. Each shell can hold a limited amount of electrons and the outer or valence shell can hold no more than 8. When all the shells hold the maximum number of electrons, all the electrons are very stable. If you add one more, so the new outer shell contains only one electron, that one valence electron is no longer stable. It will jump off one atom and on to another very easily. The three elements that do this best are copper, silver, and gold.

There are six ways to produce electricity. 1. Friction (this produces the static electricity we are all familiar with when we get a shock after touching metal on a cold day while wearing a wool sweater). 2. Chemical (batteries) 3. Heat (the principal is used in thermocouples, a device that generates a small amount of electricity when heat is applied.) 4. Light (photocells) 5. Pressure (used in gas grills to light the flame, you know, that thing you push, you hear a snap, and the flame comes on). and 6. Magnetism (all household electricity is generated by magnetism).

All the electricity that we use is done by coaxing electrons to travel together down a wire. If you pass a copper wire through a magnetic field, that field will induce the electrons to travel in one direction. Pass that wire through that magnetic field in the opposite direction and those electrons will travel in the opposite direction. Every power plant, be it coal, hydroelectric, or nuclear, does the same thing. It uses a source of energy to move wires through magnetic fields (or move magnetic fields passed wires). As one electron is coaxed to move in one direction, it coaxes another electron to move. As this chain reaction moves down the line, it travels at the speed of light (though individual electrons are moving at a fraction of that speed).