"The Sl is not static but evolves to match the world's increasingly demanding requirements."
International Bureau of Weights and Measures
Scientists and engineers constantly need to measure distances, masses, times, temperatures, densities, velocities, electrical currents, and so on. All these quantities are then expressed as a number, and this means that units are absolutely vital.
The idea of implementing common bases for all the units began with the British Association for the Advancement of Science in 1874. They suggested the centimeter for length, the gram for weight, and the second for time, which was known as the C.G.S. sytem. Prefixes such as mega- and micro- could then be used to indicate decimal multiples and submultiples.
Unfortunately, this C.G.S. system was rather inconvenient in the field of magnetism and electricity. In 1889 the Conference Generaledes Poidset Mesures decided that the meter, kilogram, and second (m.k.s.) might be more appropriate. In 1946
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