The Mystery of Electricity
Amazing! Incredible! Out of those thin wires, pure energy. In those tiny chips, pure information.
More power gliding silently and neatly through those slender wires than all the power in all the muscles of all the slaves of all the ancient world.
And more information packed in one of those microcomputer chips- one-tenth the size of a postage stamp than all the information in all the libraries of all those ancient kingdoms.
All of this power and all of this information, all of this work and all of this control, are a gift of a mysterious something called electricity.
This electricity, even more mysteriously, turns out to be a basic "glue" that holds our bodies together. A glue that holds our brain together. The same brain that is able to understand this mysterious gift.
If electrical charges are put to work in an electric current, you get things like pictures on a television set, motors turning wheels or music coming from a stereo. If electrical charges are yoked to chemical changes in cells, you get things like seeing and hearing and understanding what electricity is all about.
Understanding lightning, for instance. For thousands of years, humans noticed lightning. It was often called the wrath of the gods. Then one day in 1770 Benjamin Franklin understood it. He performed a dangerous experiment with a kite in a thunderstorm and proved that lightning was not the wrath of the gods, but instead was pure electricity.
In France at about the same time, two scientists named Dufay and Nollet discovered that pure electricity seemed to come in two different varieties, which they called positive and negative electricity. Positive and negative electricity (or charges) were attracted strongly to one another, while positive repelled positive and negative repelled negative.
In Italy, Galvani and Volta found ways to make electricity from chemicals. Volta constructed the first voltaic cell, a kind of battery which was able to generate an electric current.
In Denmark in 1820, Hans Oersted made a fundamental discovery using a wire, a battery and a compass needle. Oersted found that an electric current flowing through a wire creates a magnetic field around the wire.
A few years later Faraday in England and Henry in the United States discovered that the reverse was also true. A magnet moving near a wire would cause an electric current to flow in the wire.
Magnetism and electricity were obviously closely related.
"Interesting," some people said. "But hardly earthshaking."
"Interesting," other people said (later to be called electrical engineers), "I wonder if we couldn't make something earthshaking out of it?"
How about this? If moving a wire through a magnetic field will generate an electric current in that wire, why not greatly increase the amount of wire to be moved, greatly increase the magnetic field, redesign the spaces so that the wire can be tuned around ... and around ... and around ... continuously, powerfully- by a waterfall, a hissing steam boiler, a windmill- and we will be able to generate enough electricity to shake the world!
Of course generating electricity and producing power is only half the game. The other half is finding ways of using and controlling the vast amounts of power so generated. Thomas Edison, among others, saw the potential of electricity and besides inventing the well-known electric light bulb, he also designed and built the first commercial power generating station in New York City in 1882.
From then until now, electrical generating stations have multiplied in number, size and efficiency, and the power lines that carry this versatile energy have woven their spider webs of power around out entire spaceship earth.
Some think that these spider webs of power are the beginning of a kind of spaceship earth nervous system, sparking with power and delight.
The power is clear. What about the delight? Moving mountains is one thing delicate control is another. And electricity can do both. The art and science of controlling electricity in subtle information-rich ways is called electronics.
Scientists and engineers are never satisfied to describe a situation in words. They want to measure it, to put it into numbers, and then to relate these numbers to one another in the simplest possible ways-ideally in mathematical equations.
In 1865 a Scot named James Clerk Maxwell did just that with electricity. He invented some powerful mathematical equations to describe the electrical behavior that had been noticed and measured up till that time. Taking what was known about the relative strengths of magnetic fields and electric currents, he predicted that the speed, for instance, with which an electromagnetic field would move out from its source should be 186,000 miles a second. But wait, he said, that is also the speed of light.
His equations showed that the relative strengths of the fields could be described as a series of waves. Light can be described as a series of waves. Maybe electricity and light are just different forms of the same more basic something.
It was found to be so. Light and electricity are both indeed electromagnetic waves, part of a very wide electromagnetic spectrum. Each portion of the spectrum has a specific wavelength and frequency. At one end are the long wavelength, low frequency waves. At the other end are the short wavelength, high frequency waves. Radio waves... infrared heat waves ... visible light waves ... ultraviolet waves ... x rays ... gamma rays. All these waves are related as parts of an electromagnetic spectrum.
Just as engineers used the power of their imagination and skill to scale up Oersted's and Faraday's basic discoveries on magnetism and electric current into the modern world of electrical power, so other electronic engineers used the basic discovery of Maxwell and others to invent practical things like radio, telephone, television, computers, lasers, tape recorders.
Take tape recorders as an example. Your simplest tape recorder remembers sounds by changing the sounds of your voice or your music into electrical impulses, then into magnetic changes on the tape. These sounds can come back out, changed from magnetic fields to variations in an electrical wave, to variations in a moving membrane called a loud speaker (which imitates the moving membrane in your own throat.)
And today we have not only high fidelity stereo sound systems, but also video tapes, video discs and powerful new memory devices with names like microcomputer chips, magnetic bubbles and charge-coupled devices.
Maxwell's basic equations have also been used to strengthen and to enrich our knowledge and use of the particular wave called light. Engineers, for instance, asked if electrical waves could carry messages, why couldn't light waves carry messages?
And today it is happening in many cities around the world -telephone messages are being carried through tiny glass fibers. More messages can be carried in one of those glass fibers than could be carried in copper wires hundreds of times larger and more expensive. Soon the telephone systems will be carrying your voice everywhere on the wings of light-electromagnetic light.
This trend of doing more with less has been the rule with electrical and electronic innovation from the beginning. To be able to force so many messages, for instance, to travel on the wings of light, it was not necessary to generate more brute power. What was needed and found was more subtle intelligent control.
You see, electromagnetic light waves ordinarily come streaming out from a light source in a hopeless jumble of mixed up waves. Recently scientists found ways to stimulate atoms to give out their light in an all together, in-step way! This is called a laser. Once all the waves of light are in step, you can vary them in a controlled way to send messages.
Perhaps the best symbol for our new age of electricity is the space satellite powered by tiny photovoltaic cells which use the sun's energy to generate electrical currents. These satellites contain miniaturized and powerful computer memories, sensitive receivers and transmitters. Satellites are fast converting spaceship earth into a true global village.
Electricity is power.
Electricity is information.
Electrical power lines are linking city with city, country with country, continent with continent in ever more powerful systems.
And satellite, computers, radio, television, fiber optics, data transmission links are multiplying in ever more complex and powerful systems of information, of knowledge and delight. A linkage that is a kind of extension of the human body and the human brain.
And when we go inside that human body, that human brain, we find there that the linkages that keep muscle and sense and brain together, sparking ideas and delight and love are also electrical!
Operating rules for small spaceships.
#1. Electricity is a basic glue which holds atoms, our bodies and our worlds together. As we learn to apply and to control this glue, we will better learn to know and to do many new things.
#2. Electricity seems to be at present the most effective and most versatile way to transport both energy and information around the spaceship earth and out into space and back. It is rapidly making the world into a global village. We had best get acquainted with our neighbors. Better now than tomorrow.
Rule #3. You are electricity. In action. Aware of itself. For a little while.