Water molecules are polar. This means that one end of the molecule is positively charged, while the other is negatively charged. Opposite charges attract. Water molecules on the faucet that are eventually pulled away from the others by gravity will themselves pull together and form round drops because the charged portions of molecule attract the oppositely charged portions of another.
Geo means Earth, and centric means "in the center". So a geocentric model of the solar system would mean the Earth were at the center of the solar system, with the Sun and planets revolving around the Earth.
