RED TAPE, WHITE LIES



Why are there 60 seconds in a minute, 60 minutes in an hour and 24 hours in a day? Who decided on these time divisions? THE DIVISION of the hour into 60 minutes and of the minute into 60 seconds comes from the Babylonians who used a sexagesimal (counting in 60s) system for mathematics and astronomy. They derived their number system from the Sumerians who were using it as early as 3500 BC. The use of 12 subdivisions for day and night, with 60 for hours and minutes, turns out to be much more useful than (say) 10 and 100 if you want to avoid having to use complicated notations for parts of a day. Twelve is divisible by two, three, four, six and 12 itself - whereas 10 has only three divisers - whole numbers that divide it a whole number of times. Sixty has 12 divisers and because 60 = 5 x 12 it combines the advantages of both 10 and 12. In fact both 12 and 60 share the property that they have more divisers than any number smaller than themselves. This doesn't, of course, explain how this system spread throughout the world. Phil Molyneux, London W2.



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