India, Sept. 29 -- We check the time hundreds of times a day, but how many of us know what the numbers actually mean? Where did the time on the clock come from?

There is no one specific civilization or time period that is solely responsible for the time measurements that we use today. Our clocks and watches are the accumulation of ideas from Egyptians, Sumerians, Babylonians and Greek astronomers.

The secret behind our 24-hour day lies in the history of ancient Egypt. The Egyptians divided the day into 12 daylight hours and 12 hours of night, but their hours were not the same length as modern hours. Days were measured using a sundial and shadow clocks, while the night was measured using the appearance of constellations or decans.

It wa...