认识电力(3)

The path that leaping electrons follows depends on the material they flow through. The human body certainly will conduct current but not a lot, not like a piece of copper.

Copper has a lot of loosely held electrons, so it's a good conductor. The electrons of clay and rubber are too tightly bound to their atoms to conduct electricity.

They're said to be insulators. How electrons begin to move in the first place is a result of a force of nature called electromagnetism.

Our whole technological civilization exists because electricity can make magnetism. And, magnetism can make electricity.

It goes back to the fact that we have two kinds of forces that are present that we call electricity or electromagnetism, and those two forces are the electric force and the magnetic force. The fundamental charges are a positive charge and a negative charge.

To see these forces at work, head north and look up into the night sky. Basically, the northern lights are the result of high energy electrical currents from the sun that are caught and guided by the Earth's magnetic field.

There's electricity out there. Five, four, three, two, one.

And, we have lift-off of the Space Shuttle Columbia continuing space research through the satellite of modern technology. On February 25th, 1996, NASA and Italian researchers made a bold attempt to harness the power in the atmosphere.

They generated electricity with a satellite and a wire. It worked. Let's make sure we stay that way. Understand.

The mission was part of a new experiment of tethering satellites in space. The experiment was based on the simple principle that when you move a conductor through a magnetic field electrons start to flow.