The ruler was invented by different civilizations of different time periods. Discover the origin of the ruler with tips from a mathematics instructor in this free video on math history.

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The ruler was invented by different civilizations of different time periods. Discover the origin of the ruler with tips from a mathematics instructor in this free video on math history.

Part of the Video Series: History of Mathematics

Promoted By Zergnet

Hi I'm Steve Jones and I'm going to tell you who invented the ruler. Well which ruler is the question. First of all the ancients used all of the traditional things like spans and cubits that is the distance from this side of your thumb to that end of your finger. The length of the end of your fingers to the elbow, the length of your foot, the height of a man. These are all traditional rulers. But unfortunately they're not very accurate, because some people are two meters tall and some people are one meter fifty, some people have small hands, some people have big hands. So typically the French assembly decided in seventeen ninety one over two hundred years ago, they would define distance absolutely and they called it a meter. And it was one ten millionth of the distance from the pole to the equator on a line running through Paris. Now from seventeen ninety one that was a very difficult thing to measure, but they measured it. And in eighteen hundred and one it was made the compulsory measure for everything. So if you were a butcher and you wanted to give somebody a cubit, that is the length here of meat, sorry it had to be half a meter. This measure continued, it was a standard meter kept in a special place in Paris for two hundred years. But it wasn't very practical, so eventually they redefined it in terms of the wave length of light. But even that was then superseded by the present definition, which came in October nineteen eighty-three. Which is the distance traveled by light in vacuo when there's no air or anything else. In one divided by two nine nine seven nine two four five eight seconds. That's one two hundred and ninety nine million, seven hundred and ninety two thousand, four hundred and fifty eighth of a second. That's a long time.