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Units
The seven fundamental metric units and the quantities they measure are:
- the kilogram [kg], which mesures weight.
- the metre [m], which measures length.
- the second [s], which measures time.
- the ampere [A], which measures current.
- the degree [$^\circ$] (Kelvin or Celcius), which measures temperature.
- the mole, which mesures number of atoms.
- the candela, which measures light intensity.
The metre is defined as the distance traveled by light in a given fraction of a second.
The metric energy unit known as the joule is defined as
The luminosity of light, or candela, is measured in terms of power, designated in watts, or joules per second.