EXPERIMENTS YOU CAN DO ALMOST ANYWHERE

February 2, 1995

According to television's Bill Nye, everyone is a scientist. Prove it by trying one of these simple experiments.

* Round Shadows

To ancient astronomers, the phenomenon this simple experiment explained solved a major issue: Shine a light on a wall. Now try to find an object that always casts a round shadow, no matter which way you hold it in front of the light. How about a plate? A round paperweight? The ancients realized that the only shape that casts a curved shadow no matter which direction you shine light on it is a sphere. They looked at the moon when it was eclipsed by the Earth's shadow and realized they were living on a giant ball.

* The Power of Money

Get a nickel and a penny that was minted before 1988. (Pennies that old are made entirely of copper.) Wash them with hot water and soap. After they're clean and dry, touch the nickel and penny to the tip of your tongue very close to each other. What do they taste like? Where both metals touch your tongue, you taste sweetness. That's because they're setting up a very small electrical flow in your saliva. That electricity stimulates your taste buds with a ``sweet'' signal. But it all comes from the metals.

* Television Blinks

Wave a pencil in front of the TV when it's on. The waving pencil seems to have several images. That is caused by the picture on the television being created and turned off 60 times per second - twice for each image it shows. When you wave the pencil in front of a regular light bulb, you won't see any multiple images. Now wave it in front of neon or fluorescent bulb. You'll see the multiple pencils again. It's because those types of lights are blinking on and off 60 times a second, too. The blinking of lights comes from power stations, where electricity is generated. It's made in a way that turns the electricity off and on again constantly - at 60 Hertz, or blinks per second.