ATOMIC CLOCK(1949)

THE RACE FOE THE PERFECT TIMEKEEPER BEGINS.

         Build by the British in 1955, this atomic clock depends on the vibration of Caesium exposed to radio waves                      
Most type of clocks rely on the oscillation of a solid body, be it a pendulum, balance wheel, or a quartz crystal, but each suffers from the effect of pressure, temperature and gravity . Atom however, vibrates a fixed number of times per second. Both the U.S. national bureau of standard and United Kingdom’s national physic laboratory tried to take advantage of these vibrations. Time measuring devices have also depended on the spin of the Earth, but these suffer from seasonal effect tidal friction.

Sometimes a clock updated by radio signal is called atomic clock which is used in ultraviolet region of electromagnetic spectrum of atoms, electron transition of microwave, optical. The atomic clock is works on the principle of atomic physic; it uses the microwave signal that electron in atoms emit when they change energy level. The accuracy of atomic clock depends on two factors namely temperature

In 1949, the American Build a quartz clock that was synchronized by the 24 GHz vibration of low pressure gaseous ammonium molecule. The British , under the leadership of physicist Louis Essen (1908-1997), used the oscillation of an electric circuit synchronized to the vibration of caesium atoms the first caesium clock begin build in 1955. The Caesium was kept in a tune able microwave cavity and the relied on the fact that there were 9,192,631,770 transitions between two hyperfine ground- state energy levels every second. This number defined the second, as opposed to the old definition of their being 86,400 second in one day. The good atomic clock accurate to one part in 1,014 and therefore would take about 3 million years to lose or gain a second

Four atomic clocks are used in each of the many satellite of the global positioning system and comparisons of electromagnetic wave travel times enable position on the earth to be measured precisely. The clocks are also used by geophysicist to monitor variation in the spin rate earth and the drifting of the continent.