The Basics


What do some of the metric prefixes represent?

This kind of clock cannot be used at night of when the sun doesn’t shine. To remedy this problem, timing devices such as notched candles were created. Later, hourglasses and water clocks (clepsydra) became quite popular. The first recorded description of a water clock is from the sixth century B.C.E. In the third century B.C.E. Ctesibius of Alexandria, a Greek inventor, used gears that connected a water clock to a pointer and dial display similar to those in today’s clocks. But it wasn’t until 1656 when a pendulum was used with a mechanical clock that these clocks kept very accurate time.

Prefixes in the metric system are used to denote powers of ten. The value of the exponent next to the number ten represents the number of places the decimal should be moved to the right (if the number is positive), or to the left (if the number is negative). The following is a list of prefixes commonly used in the metric system:

Sundials are a very old way to tell time. While accurate, they are limited by the fact that they only work when the sun is shining.

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