Cesium

Discovered by Gustov Kirchoff and Robert Bunsen of Germany in 1860, cesium is a very soft and ductile light grey metal. It's name comes from the Latin word "coesius", meaning sky blue. The name was chosen for the blue lines that run through the metal's spectrum. Cesium turns to a liquid in a warm room. Only a few metals do this- the others being gallium, francium, and mercury.

A cesium reaction to water

Cesium is extremely reactive, having the most alkaline of all elements. It causes explosions upon contact with water producing cesium hydroxide, which is a very strong base that has the ability to corrode glass.

A very interesting fact about cesium is that it is used in atomic clocks. Atomic clocks are extremely accurate. In fact, cesium was used in the clocks that record the official world time. Currently it neither gains nor loses a second in more than 60 million years.