MadSci Network: Science History

Re: Why are there 60 minutes in an hour and 24 hours in a day ?

Date: Sun Mar 22 21:47:59 1998
Posted By: Nick Hoffman, Physics
Area of science: Science History
ID: 888498953.Sh


This all dates back to the Ancient Babylonians who liked to count in base 60. Ratios of 6, 12, 60, and 360 were seen by them as being 'round' numbers in the same way that we use base 10 and see 5, 10, 100 etc as useful numbers to divide things up into.

See: HistTopics/Babylonian_and_Egyptian.html

The Babylonians divided the sky into the 12 signs of the Zodiac, and a circle into 360 degrees. They divided the day and night each into 12 hours (although in many time systems the lengths of these varied between summer and winter! Babylon was rather nearer the equator than Liverpool, so they didn't get too confused with this). The hour was split into 60 minutes and a minute into 60 seconds.

All these numbers have survived for 4000 years, despite the fact that we have changed our numbering system to base 10! In England, when I was young, we still measured with feet, each divided into 12 inches. The Americans still do! [By the way, do you know where the mile comes from? It's Roman, not Babylonian!]

The year is nearly 360 days long and the Babylonians split it into 12 months. Other civilizations based their calendar on the moon and had 13 months. We still have problems with this today because Easter is based on the lunar calendar and migrates around the Julian calendar in a complex way. Chinese new year is still based on the Lunar calendar.

If you don't like base 60 time, try this webpage for a man who thinks we should go decimal!


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