Can you guess — what is 1 metre?

Take a strip of paper from the roll and tear off one metre — just using your sense of distance.

Then place it on the steel ruler and see how close you were.

How good is your sense of length?

What is one metre, really?

 

When the first metre was created in 1799, it was defined as one ten-millionth of the distance from the equator to the North Pole.

 

Later, metre prototypes made of platinum–iridium were produced and served as the international standards for more than a century.

 

Since 1983, the metre has no longer been tied to a physical object but has been defined using the speed of light in a vacuum: 1 metre is the distance light travels in 1/299,792,458 of a second.

 

Thanks to this definition, the metre can now be reproduced with high accuracy anywhere in the world — using only light and the measurement of time.