Centimeter-Gram-Second System

(redirected from cgs)
Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.

centimeter-gram-second system

[¦sent·ə‚mēd·ər ¦gram ′sek·ənd ‚sis·təm]
An absolute system of metric units in which the centimeter, gram mass, and the second are the basic units. Abbreviated cgs system.

Centimeter-Gram-Second System


(cgs system), the system of units of physical quantities that is based on the three fundamental units of the centimeter for length, the gram for mass, and the second for time.

In 1861 the British Association for the Advancement of Science appointed a committee on electrical standards, whose membership included such leading physicists of the day as W. Thomson (Lord Kelvin), J. Maxwell, and C. Wheatstone. The committee proposed that a system of units based on fundamental units of length, mass, and time be adopted for mechanics and electrodynamics. Ten years later, the association formed a new committee, which made a final choice of the centimeter, gram, and second as the fundamental units. The First International Congress of Electricians, which was held in Paris in 1881, also adopted the cgs system. Since then, the system has been widely used in scientific research. Since the introduction of the International System of Units (SI), the use of cgs units has been permitted alongside SI units in physics and astronomy.

With respect to mechanical measurements, the most important derived units in the cgs system are as follows: speed, cm/sec; acceleration, cm/sec2; force, dyne (dyn); pressure, dyn/cm2; work and energy, erg; power, erg/sec; dynamic viscosity, poise (P); and kinematic viscosity, stokes (St).

For electrodynamics, two cgs systems—the cgs electromagnetic system and the cgs electrostatic system—were originally adopted. The electromagnetic system is based on Coulomb’s law of the force between two point magnetic poles, and the electrostatic system on Coulomb’s law of the force between two point electric charges. In the cgs electromagnetic system, the permeability of empty space μ0 is dimensionless and is taken as 1. The permittivity of empty space ɛ0 = 1/c2 sec2/cm2, where c = (2.99792458 ± 0.000000012) X 1010 is the numerical value of the speed of light in cm/sec. The cgs electromagnetic system includes the following units: magnetic flux, maxwell (Mx); magnetic flux density, gauss (G); magnetic field strength, oersted (Oe); and magnetomotive force, gilbert (Gb). Special names have not been adopted for the electrical units in this system.

In the cgs electrostatic system, ɛ0 = 1, and μ0 = 1/c2 sec2/cm2. The electrical units of this system have not been given special names. Their sizes are in general inconvenient for measurements, and they are used primarily in theoretical work.

Elements of the electromagnetic and electrostatic cgs systems are mixed in the Gaussian system, which has become the most widely used system in the second half of the 20th century. In this system, μ0 = 1, and ɛ0 = 1. The magnetic units of this

Table 1. Relations between the most important cgs units and the corresponding SI units1
QuantitySI systemcgs electromagnetic systemcgs electrostatic systemGaussian system
1In table, c is the numerical value of the speed of light in cm/sec
Force.....................1 N10-5N10-5N10-5N
Work, energy ................1 J10-7J10-7J10-7J
Dynamic viscosity .............1 N.sec/m20.1 N.sec/m20.1 N.sec/m20.1 N.sec/m2
Kinematic viscosity ............1 m2/sec10-4m2/sec10-4 m2/sec10-4m2/sec
Current....................1A10A10/c A10/c A
Electric charge..........1C10C10/cC10/cC
Electric potential..............1V10-8V10-8c Vl0-8c V
Electric resistance.............10-9 Ω10-9C2Ω10-9C2Ω
Electric capacitance ...........1F109Fl09/c2 Fl09/c2 F
Magnetic field strength ..........1 A/m103/(4π) A/m103/(4πc) A/m103/(4π) A/m
Magnetic flux density ...........1T10-4T10-4cT10-4 T
Magnetic flux ................1 Wb10-8 Wb10-8c Wb10-8 W

system are identical to those of the cgs electromagnetic system, and the electrical units are identical to those of the cgs electrostatic system.

Table 1 shows the relations between the most important units of the three cgs systems and the corresponding SI units.


Burdun, G. D. Spravochnik po Mezhdunarodnoi sisteme edinits. Moscow, 1971.


References in periodicals archive ?
For additional information on the Deluxe-China Film partnership, ShowEast attendees can stop by booth #115 on the ShowEast exhibit floor, where the companies will be demonstrating the CGS format through Thursday.
Among the companies using CGS contact center and BPO services including help desk and tech support are Avon, Cuisinart, Dell, Fuji-Film, Honeywell, Intercontinental Hotels Group, and Sprint.
With five global locations, 2,500 customer service agents and support in 14 languages, CGS has the ability to reengineer, supplement, or completely manage customer support services for virtually any size company or government agency.
The LET focuses on CGS and Joint Service Workstation (JSWS) configuration, operation, maintenance, and repair.
Three World Financial Center is the perfect fit for CGS.
The CGS consists of a cellular concrete base for storage or ballast.
Only days before the trial did a Judge in Alexandria, Virginia, rule that CGS could not proceed with its claim for unjust enrichment.
In less than six months from contract award, JPSS CGS was ready to fully support the scheduled JAXA launch.
CGS offers end-to-end, technology-enabled business solutions and services including ERP, CRM, PLM, PSA, IT services, systems integration, application development, learning, ILT, staffing, IT help desk, BPO and outsourcing solutions.
The LET focuses on CGS and JSWS configuration, operation, maintenance, and repair.
CGS currently serves Medicare beneficiaries, health care providers and medical equipment suppliers in 33 states.
The teams honored in our 2008 'FAO Research Awards of Distinction' -- including CGS and AOL -- reflect this vision in action.