An atomic clock is supposed to be one of the most accurate time-keeping devices in human history. Caesium is what powers an atomic clock as its atoms keep it exact. The atomic clock is the device used as the standard measure of time. A second in the atomic clock is defined as the amount of time taken by the caesium atom to vibrate 919,26,31,770 times between energy levels!
Caesium is a rare element. It is a silver-white, shiny metal with brilliant blue spectral lines. The element’s name comes from ‘caesius’, a Latin word meaning ‘sky blue’. It is the softest metal, with a consistency of wax at room temperature.
Caesium will melt in your hands! However, be very cautious! The element might explode in the air, as it is highly reactive to moisture. Since caesium reacts violently with water, it is treated as a hazardous material, and is often kept under a layer of kerosene or mineral oil, or in a vacuum. This prevents the metal from reacting and igniting in the air.
Caesium was the first element to be discovered with a spectroscope. It was discovered in 1860 by German chemists Robert Bunsen and Gustav Kirchhoff when they were analyzing the spectrum of mineral water. Apart from its use in atomic clocks, caesium is used in excavation of petroleum. The atomic number of caesium is 55, and the symbol is Cs.
Pictures credit: google
