Bending water to your will
Description
A thin stream of water flows out of a bottle. The stream can be deflected by bringing up a “magic wand” which has been charged with chemical magic.
Requires
- A bottle or other container that will produce a continuous, thin stream of water.
- A plastic rod, or piece of plastic pipe.
- A piece of material to charge up the plastic pipe. Nylon stockings work well but many other materials are also suitable.
Method
Once the thin stream of water is flowing charge the “magic wand” by rubbing it vigorously with the nylon stockings (or other material of your choice). Bring the “wand” up close to the stream of water, without touching it. As the plastic rod gets closer to the stream of water it will be deflected.
Principle
The static electricity which has been generated on the rod is sufficient to attract the water stream. In the show this is attributed to the permanent dipole moment of the water molecule. There appears, however, to be different explanations for the effect. While Vemulapalli and Kukolich (J. Chem. Ed. 73 887-8 (1996)) are satisfied with an explanation drawing on only a combination of permanent and induced dipole moments Ziaei-Moayyed and Goodman (J. Chem. Ed. 77 1520-2 (2000)) invoke a variety of mechanisms which could be responsible for charging individual droplets.
Tip
Any experiment which relies on static electricity will work best in an atmosphere of low relative humidity. A thin stream of water can be produced by sealing the end of a plastic pipette into a plastic bottle.
Safety
Water on the floor is a slip hazard. Spillages should be mopped up as soon as possible.