PURPOSE: To demonstrate polarization of water molecules.
DESCRIPTION: An three foot long section 2x4 is carefully centered and balanced on a watch glass, so that it can rotate about the balance point. A charged rod by (either positive or negative) is held alongside the 2x4. A force is exerted on the 2x4 and it rotates toward the rod, so that you can pull the 2x4 around with the rod. Changing the charged rod to the opposite polarity rod creates the same force, and again the 2x4 can be pulled around by the rod. The charge of the rod polarizes the dipolar water molecules in the wood.
EQUIPMENT: A three foot long wooden 2x4 that is stored against the wall behind
the electricity and magnetism cabinets, charging materials from the electricity and
magnetism cabinets, a watch glass to use as low-friction pivot is stored in the glass
drawer in the chemical cabinet by the sink.