MEASURING TIME

Thousands of years ago, when measured with a hint of the sun, hourglasses and water clocks. Around 2000 BC, people in Babylon, measuring time throughout the day by looking at the shadow of the sun. The shadow is shorter lunch time approached. A long shadow, a new day starts (morning), or will expire (afternoon). Around 1380 BC, water clocks and hourglasses are made in Egypt. Hours of water ever found in the tomb of Amenhotep I (1500 BC). The shape vessel with curved sides and the bottom of small holes for dripping water. Hourglass consists of two tubes (top and bottom) and contains dry sand. From the tube top, gently pouring sand into the bottom tube, through a small pipe that connects the two. Once all the sand has been spilled into the bottom tube, a span of one hour has passed. Hourglass then reversed so that the tubes are filled with sand on top, and pouring sand again. and so on. Late 1200s, mechanical clocks began to flourish in Europe. One of the oldest mechanical clock was made in France in 1360. Large size, made of iron, with a ballast weighing 220 kg. The author Henry de Vick on orders of King Charles V. Mid XIV century, many of the mechanical clock appeared in the tower of the city, in Italy. One of them made by Giovanni Dondi in 1364. Also mounted on Salisbury Cathedral, including the first generation of mechanical clock, built in 1386. Hours generally use this model as a mover and gear weight. Beginning in the 1500s, Peter Henlein, a locksmith from Numberg, Germany introduced the spring as a replacement ballast device driver hours. Clock size becomes smaller, no longer at the clock. spring was made from a bent steel circular. year 1656, Christian Huygens, mathematician, physicist and astronomer from the Netherlands, made the first pendulum clock. Huygens' work has an error of less than a minute a day. Early good accuracy, which can be achieved. Error was reduced to a mere 10 seconds a day, after the repair. Huygens pendulum clock's first new work created in 1673. Because the precision of movement and pendulum escapement mechanism (a kind of gear that does not keep the weight down more quickly), the velocity of time on the watch can be set constant. In 1680, also produced similar hours in Geneva, London and Paris. 1921, W.H. Shortt make a clock with two pendulums. Then came the quartz watch that works based on piezoelectric, electric power produced quartz crystal. Spearheaded by G. Alter Cady in 1922. The accuracy of the clock appear increasingly intensified since the atomic clock in 1949. 1969 the newly created atomic clocks with accuracy up to a billion seconds a day. Figures slipping of less than a second in 100,000 years. Regular and constant vibrating atoms, unbounded space and time. Vibrations of cesium atoms of hydrogen or today, for example, exactly the same as the atomic vibrations that a million years ago. So that in 1967 scientists worldwide agree, cesium atoms as units of time International. 9,192,631,770 times a second cycle of synchronized with cesium atomic radiation.