Centimetre gram second system of units

The centimetre-gram-second system (CGS) is a system of physical units. It is always the same for mechanical units, but there are several variants of electric additions.

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The system goes back to a proposal made in 1832 by the German mathematician Carl Friedrich Gauss and was in 1874 extended by the British physicists James Clerk Maxwell and William Thomson with a set of electromagnetic units. The sizes (order of magnitude) of many CGS units turned out to be inconvenient for practical purposes, therefore the CGS system never gained wide general use outside the field of electrodynamics and was gradually superseded internationally starting in the 1880s but not to a significant extent until the mid-20th century by the more practical MKS (metre-kilogram-second) system, which led eventually to the modern SI standard units.

Related Topics:
1832 - Carl Friedrich Gauss - 1874 - James Clerk Maxwell - William Thomson - 1880s - SI

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CGS units are still occasionally encountered in older technical literature, especially in the United States in the fields of electrodynamics and astronomy. SI units were chosen such that electromagnetic equations concerning spheres contain 4?, those concerning coils contain 2? and those dealing with straight wires lack ? entirely, which was the most convenient choice for electrical-engineering applications. In those fields where formulas concerning spheres dominate (for example, astronomy), it has been argued that the CGS system can be notationally slightly more convenient.

Related Topics:
Electrodynamics - Astronomy

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Starting from the international adoption of the MKSA standard in the 1940s and the SI standard in the 1960s, the technical use of CGS units has gradually disappeared wordwide, in the United States more slowly than in the rest of the world. CGS units are today no longer accepted by the house styles of most scientific journals, textbook publishers and standards bodies.

Related Topics:
MKSA - SI - United States

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The units gram and centimetre remain useful within the SI, especially for instructional physics and chemistry experiments, where they match well the small scales of table-top setups. In these uses, they are occasionally referred to as the system of ?LAB? units. However, where derived units are needed, the SI ones are generally used and taught today instead of the CGS ones.

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