Remote Control Roller

 

15 minutes

What do I need?

  • empty soda can
  • blown-up balloon
  • your hair
 ...Can racing across floor

 What do I do?

1Put the can on its side on a table Can on table topor the floor -- anyplace that's flat and smooth. Hold it with your finger until it stays still.

 

2Rub the balloon back and forth on your hair really fast.

Rub the balloon on your hair

3Hold the balloon about an inch inThe can follows the balloon! front of the can. The can will start to roll, even though you're not touching it!

 

 

 

4Move the balloon away from the The can follows the balloon!can -- slowly -- and the can will follow the balloon.

 

5If you move the balloon to the other side of the can, the can will roll in the other direction.

 

Can races across floor!

6How fast will the can roll? How far can you roll it before the can stops? Will it roll uphill?

7If you have some friends with cans and balloons, you can have a race across the room or down the sidewalk.

Rub a balloon on your head and you can...

Bend Water
Turn on the faucet in your bathroom or kitchen. Don't run the water too hard, but more than a little trickle. Now rub a balloon on your head and hold the balloon near the water. The stream of water will bend toward the balloon!

Give yourself funny hair
Rub the balloon on your head, then pull it away. Your hair will stick out and look really funny. (This can also happen when you comb your hair with a plastic comb.) What if you hold the balloon near your arm? Can you feel the hairs on your arm move? Will it work on doll hair? How about animal fur?

Stick the balloon to your face!
Once you've rubbed the balloon on your head, it will stick to other things -- with no glue. You can stick it to the wall, to the TV, or even to your face!

 Stick the balloon to your face!

What's Going On?

Why does the soda can roll?

With Remote Control Roller, basically, you pile up electrons on one thing and use them to attract the protons in something else. When you rub a balloon on your hair, it ends up loaded with electrons. Those electrons can attract the protons in a soda can, the protons in a trickle of water, the protons in your hair, or the protons in a wall.

Why do clothes stick together in the dryer?

The attraction between protons and electrons can also make clothes stick together in the dryer.

 

When you dry clothes in the dryer, different fabrics rub together, and electrons from a cotton sock (for instance) may rub off onto a polyester shirt. That's why clothes sometimes stick together and make sparks when you pull them apart. You may have used antistatic sheets in your dryer. As these sheets bounce around with your clothes, they add a uniform antistatic coating to the fabric. Rather than cotton rubbing against polyester, you've got the antistatic coating on the cotton rubbing against the antistatic coating on the polyester. No electrons rub off-and you don't get any static cling.

Wow! I didn't know that!

A Xerox machine uses static electricity to make copies. When you rub a balloon on your head, the balloon is charged with electricity. Inside a Xerox machine is a plastic drum that is also charged. When you put a piece of paper on the glass, a copy of it goes onto the drum. Where there were dark places on the paper, the static charge on the drum attracts the black plastic toner powder. Then the powdered places go onto a blank piece of paper, and the paper is heated. The toner melts and makes black letters on the new piece of paper.


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This and dozens of other cool activities are included in the Exploratorium's Science Explorer books, available for purchase from our online store.

About the Books

Published by Owl Books,
Henry Holt & Company, New York,
1996 & 1997

ISBN 0-B050-4536 & ISBN 0-8050-4537-6,
$12.95 each






© 1998 Exploratorium