# Physics:Dyne

Short description: Unit of force
dyne
Unit systemCGS units
Unit ofForce
Symboldyn
Conversions
1 dyn in ...... is equal to ...
CGS base units   1 g⋅cm/s2
SI units   10−5 N
British Gravitational System   2.248089×10−6 lbf

The dyne (symbol: dyn; from grc δύναμις (dúnamis) 'power, force') is a derived unit of force specified in the centimetre–gram–second (CGS) system of units, a predecessor of the modern SI.

## History

The name dyne was first proposed as a CGS unit of force in 1873 by a Committee of the British Association for the Advancement of Science.[1]

## Definition

The dyne is defined as "the force required to accelerate a mass of one gram at a rate of one centimetre per second squared".[2] An equivalent definition of the dyne is "that force which, acting for one second, will produce a change of velocity of one centimetre per second in a mass of one gram".[3]

One dyne is equal to 10 micronewtons, 10−5 N or to 10 nsn (nanosthenes) in the old metre–tonne–second system of units.

1 dyn = 1 g⋅cm/s2 = 10−5 kg⋅m/s2 = 10−5 N
1 N = 1 kg⋅m/s2 = 105 g⋅cm/s2 = 105 dyn
v · d · e 1 N 1 dyn 1 kp 1 lbf newton(SI unit) dyne kilogram-force, kilopond pound-force poundal ≡ 1 kg⋅m/s2 = 105 dyn ≈ 0.10197 kp ≈ 0.22481 lbf ≈ 7.2330 pdl = 10−5 N ≡ 1 g⋅cm/s2 ≈ 1.0197 × 10−6 kp ≈ 2.2481 × 10−6 lbf ≈ 7.2330 × 10−5 pdl = 9.80665 N = 980665 dyn ≡ gn ⋅ (1 kg) ≈ 2.2046 lbf ≈ 70.932 pdl ≈ 4.448222 N ≈ 444822 dyn ≈ 0.45359 kp ≡ gn ⋅ (1 lb) ≈ 32.174 pdl ≈ 0.138255 N ≈ 13825 dyn ≈ 0.014098 kp ≈ 0.031081 lbf ≡ 1 lb⋅ft/s2 The value of gn as used in the official definition of the kilogram-force is used here for all gravitational units.

## Use

The dyne per centimetre is a unit traditionally used to measure surface tension. For example, the surface tension of distilled water is 71.99 dyn/cm at 25 °C (77 °F).[4] (In SI units this is 71.99×10−3 N/m or 71.99 mN/m.)

## References

1. Thomson, Sir Wl; Professor GC, Foster; Maxwell, Professor JC; Stoney, Mr GJ; Professor Flemming, Jenkin; Siemens, Dr; Bramwell, Mr FJ (September 1873). "First Report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units". in Everett, Professor. Forty-third Meeting of the British Association for the Advancement of Science. Bradford: Johna Murray. p. 224. Retrieved 8 April 2012.
2. Gyllenbok, Jan. "dyne". Encyclopaedia of Historical Metrology, Weights, and Measures, Volume 1. Birkhäuser. p. 90. ISBN 9783319575988. Retrieved 20 April 2018.
3. "Dyne". Dyne. Chicago: Compton. 1914.
4. Haynes, W.M., ed (2015). "Surface tension of common liquids". CRC Handbook of Chemistry and Physics (96nd ed.). CRC Press. p. 6-181. ISBN 9781482260977.