Cs

Cesium

In 1860 German chemists Robert Bunsen and Gustav Kirchhoff were analyzing mineral water from a spring in Dürkheim using their newly invented spectroscope. As they examined the spectrum, they noticed two brilliant blue lines. They had found a new element, naming it “caesium” after the Latin word for “sky blue.” Bunsen evaporated down over 44,000 liters of mineral water to obtain just a few grams of cesium chloride. 

Cesium atomic clocks are among the most accurate timekeeping devices ever created, utilizing the precise oscillations of cesium atoms to define the second and maintain exceptionally stable time measurements.