# Metric measurements

It is nature that has given **light a velocity** and it is man who has given the unit of **velocity and time** , which is as per his yardstick. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the **North Pole** . In 1799, it was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of **wavelengths** of a certain emission line of krypton-86. In 1983, the current definition was adopted.

In the **International System of Units** (SI), the basic unit of length is the metre and is now defined in terms of the speed of light. A meter has been officially defined to be the distance traveled by light in a **vacuum** in 1/299,792,458 second. All other length and distance measurements in the metric system derive from the meter (eg. km= 1000m, 1m= 1000mm). The centimetre and the **kilometre** , derived from the metre, are also commonly used units.

## Conversion

The process of **changing** from one type of system to another. The process of **conversion** depends on the specific situation and the intended purpose. This may be governed by regulation, contract, technical specifications or other published **standards** . A conversion factor is used to change the units of a measured quantity **without changing** its value.

**Related Topics**

- Metre (m) to Centimetre (cm) Conversion
- Metre (m) to Millimetre (mm) Conversion
- Metre (m) to Inches (in) Conversion
- Metre (m) to Feet (ft) Conversion
- Metre (m) to Yard (yd) Conversion
- Metre (m) to Kilometre (km) Conversion
- Metre (m) to Miles (mi) Conversion
- Metre (m) to Nautical miles (nm) Conversion
- Centimeter (cm) to Meter (m) Conversion
- Centimeter (cm) to Millimeter (mm) Conversion
- Centimeter (cm) to Inches (in) Conversion
- Centimeter (cm) to Feet (ft) Conversion
- Centimeter (cm) to Yard (yd) Conversion
- Centimeter (cm) to Kilometer (km) Conversion
- Centimeter (cm) to Miles (mi) Conversion
- Centimeter (cm) to Nautical miles (nm) Conversion