Steve Varner, age 10, of Winslow, Arizona, for his question:
How does an electric eel generate electricity?
The electric eel has a thick snaky body about nine feet long. He is a South American cousin of the catfishes and tae goldfishes and not at all related to the true eels. He lives in lazy streams where the muddy water tends to be cloudy. And this remarkable fish has his own built in battery, which is almost six feet long. It generates electricity and when lie turns on its full power, its electric shocks are strong enough to stun a horse.
Electricity reminds us of the power lines that carry current to light, warm and cool our homes, run the TVs and the toasters, electricity created by man made generators and tamed to do useful chores. But much more elec¬tricity is created in the world of nature.
Nature creates huge flashes of electricity in every streak of lightning. On a much smaller scale, nature provides every living cell with a tiny chem¬ical battery to generate tiny doses of electricity. Your nerves use electric energy to send signals to and from your brain.
The electric eel has a super sized chemical battery that can shoot electric shocks through the water. This remarkable electric organ begins about three feet behind his head and stretches nearly six feet along his snaky body, almost to the tip of his tail. It is made of rather squat little cells, crowded together in layers of fatty tissue.
Scientists suspect that ages ago the ancestors of the electric eel had ordinary living cells that used electric signals to make the long muscles in their tails contract and relax. For some reason, they changed into special cells called electroplaxes. These electroplaxes work somewhat like a multitude of mini flashlight batteries. They can send signals from cell to cell and also send electric shocks outside his body.
His built in chemical battery is in three parts. The strongest elec¬tric organ is composed of two long layers of tissue that reach almost to the end of his tail. Underneath are two pairs of shorter layers. These smaller electric organ give off fast, creak shocks all the time. Their electrical impulses go through the water and bounce back from stones, fish, and other objects. These echos are detected by sensitive pits in the elec¬tric eel's head. They show him objects in the murky water around him.
When a human being or a large animal enters the water, he feels threatened. Then he switches to his main battery and sends a few mighty powerful electric shocks through the water. These jolts are strong enough to stun or even kill a man.
The electric eel's remarkable built in battery has one serious draw¬back. Usually he shares his muddy backwater with a group of other electric eels and all of them send out continuous streams of their weak electric shocks. The older electric eels are blind or almost blind. Scientists suspect that all the electricity in the crater destroys their eyesights.