The word ‘clock’ comes from the French word “cloche” meaning bell. The Latin word for bell is glocio, and the German is glocke. The clock, one of the oldest human inventions, has witnessed usage of devices operating on several different physical processes over the millennia, culminating in the clocks of today.
Sun clocks : The Ancient Egyptians were the first ones to take timekeeping to a new level with the invention of the obelisk and later on to Sun Clocks which measured time with the help of shadows, but only during sunny days.
Water clocks : Later on, Egyptians used water clocks in around 1400BC. The principle was simple – fill a container with water and allow it to flow at a constant rate into another chamber that operated on some float mechanism moving a lever to show the hours.
Mechanical clocks : In 1656, the pendulum clock was invented by Christian Huygens based on the study of pendulum motion by Galileo Galilee, making clocks more accurate. He determined the mathematical formula that related pendulum length to time and had the first pendulum-driven clock made. In 1577, Jost Burgi invented the minute hand.
Quartz Clock : In 1927, Canadian-born telecom engineer, Warren Marrison, developed a very large, highly accurate Quartz Clock based on the regular vibrations of a quartz crystal in an electrical circuit building on earlier work in piezoelectricity. Then came along today’s Digital Clocks, which is available as hand watches, home clocks and as watches in cell phones and computers. The digital clocks work by lithium batteries.