Lead oxide crystals, coloured scanning electron micrograph (SEM). Lead is a heavy, soft, ductile metal that, under normal conditions, does not react with water. However, when it comes into contact with moist air, its reactivity with water increases. A small lead oxide (PbO) layer forms at the surface of the metal, seen here as leaflike crystals. Magnification: x2085 when printed 10 centimetres tall.
