Electrostatic Motor

Make a meter stick spin


A charged PVC rod can be used to make a meter stick balanced on a watch glass spin around. With several people the meter stick becomes the rotating core of an electrostatic motor.



Place the watch glass or spoon, so that each makes a dome, near the edge of a table.

Balance the meter stick, or the 2 x 4, on the watch glass.

Optional, Hang the meter stick from a string at its middle. Balance the meter stick so that it is horizontal.

To Do and Notice

Rub the PVC tube with the wool until it crackles with electricity.

Hold the PVC near one edge of the meter stick. Notice that the meter stick is attracted to the PVC pipe and begins to move toward it. Keep the PVC pipe moving and the meter stick will follow.

With 4 people and 4 charged PVC rods spread around the table the meter stick can be passed from one person to the other and made to rotate continuously.

What's Going On?

The charged PVC rod attracts the uncharged meter stick. Charged things attract uncharged things.

The negative PVC makes the near side of the meter stick positive and the far side negative. The meter stick becomes electrically polarized.

The PVC then attracts the nearby positive charges more strongly than it repels the more distant negatives. The meter stick is then attracted to the PVC rod.

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© 1999

19 Mar 99