Turn your sink on so the water runs in a very thin stream. Try to get it at thin as a piece of spaghetti. The thinner the better, but it does need to be a constant stream, not dripping. Rub the balloon on the piece of wool/fur/hair. Do this at least 20-30 times. Bring the balloon close to the stream of water; without it touching the water. Observe what happens to the stream of water.
WHY? Why did the water behave the way it did when the balloon was brought close to it?