Mercury is the only metal that is a liquid at room temperature. Mercury's chemical symbol is Hg. The Hg comes from the Greek word hydrargyrum, which means liquid silver. Because of its silvery appearance and the way it moves, the metal was also called quicksilver. The chemical is named for the Roman god, Mercury, who was known for his speed and mobility. Students will learn about the sources of mercury and its effects on the environment; coal-burning...