PURPOSE: A simple trick easily solved with the application of electrostatic force and the polar nature of water molecules.

DESCRIPTION:A nickle is balanced on its edge in the center of a piece of paper, and a wooden match is balanced on the nickle. A plastic cup is placed upside down over the nickle and match, and a second nickle is balanced on bottom of the upside-down cup. The question is: how to remove the matchstick without disturbing either of the nickles? The answer lies in the polar nature of the water in the matchstick, which is affected by the presence of a nearby charged rod. You can see this in action by clicking on the photo above to view our helpful video. Some other options that don't work include yanking out the piece of paper or trying to dislodge the matchstick with a magnet.

SUGGESTIONS: See Question of the week #243 for information on using this demonstration to enhance class involvement.

REFERENCES:PIRA Unknown

EQUIPMENT: 2 nickles, matchstick, and plastic cup, as shown.

SETUP TIME: 5 minutes.