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Gilbert's Versorium

Grade Level: K - 6

Discussion:

Some materials attract better than others. A man named William Gilbert proved this 300 years ago with his invention the versorium. Versorium is from a Latin word which means "turn about." You will see why this name is so appropriate when you make and use your own versorium.

Materials:

plastic drinking straw
10" length of sewing thread
plastic ball point pen
candle

Procedure:

1) Tie the thread to the exact center of the straw and ask a friend to hold it suspended.

2) Rub the pen on a rug until it feels warm. By doing this, you are attempting to build up a charge.

3) Wait until the straw is hanging motionless. Bring the "charged" pen close to one end of the straw. What happens?

4) Use the pen to make the straw spin in one direction and then in the other. The plastic in the pen is able to attract well.

5) Do the same experiment using the candle instead of the pen. Rub the candle on the rug. Bring it toward the straw. What happens? Is wax able to attract as well as the plastic? Does it attract at all?