Kilogram

The kilogram (kg) is the unit of mass (m). The name is derived from the Greek words kilo (κιλό), meaning "thousand", and gramma (γράμμα), known in the Late Antiquity as 1/24 part of a Roman uncia or about 1.14 gram.

The unit kilogram is defined by fixing Planck's constant to be:

h = 6.626,070,15·10^-34 J·s

where the meter and the second are defined in terms of speed of light and atomic clock.

History

The kilogram was defined by the French Academy of Sciences in 1795 as the mass of 1 liter of water.

Related units

• base units
• calorie
• centimeter
• electronvolt
• erg
• gram
• joule
• meter
• second
• watt