Unlike many substances, water expands as it freezes. An ice cube takes up about 9% more volume than the water used to make it. If you pour a handful of salt into a full glass of water, the water level will actually go down rather than overflowing the glass. Similarly, if you mix half a liter of alcohol and half a liter of water, the total volume of the liquid will be less than one liter. There is about 1/2 lb or 250 g of salt (NaCl) in the average adult human body. A pure element takes many forms. For example, diamond and graphite both are forms of pure carbon. Many radioactive elements actually glow in the dark. The chemical name for water (H 2 O) is dihydrogen monoxide. The only letter not appearing on the periodic table is J. Lightning strikes produce O 3 , which is ozone, and strengthen the ozone layer of the atmosphere. The only two non-silvery metals are gold and copper . Although oxygen gas is co...