# Dyne

The **dyne** (symbol **dyn**, from Greek δύναμις, *dynamis*, meaning 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/s
^{2}= 10^{−5}kg⋅m/s^{2}= 10^{−5}N

- 1 N = 1 kg⋅m/s
^{2}= 10^{5}g⋅cm/s^{2}= 10^{5}dyn

newton (SI unit) | dyne | kilogram-force, kilopond | pound-force | poundal | |
---|---|---|---|---|---|

1 N | ≡ 1 kg⋅m/s^{2} |
= 10^{5} dyn |
≈ 0.10197 kp | ≈ 0.22481 lbf | ≈ 7.2330 pdl |

1 dyn | = 10^{−5} N |
≡ 1 g⋅cm/s^{2} |
≈ 1.0197 × 10^{−6} kp |
≈ 2.2481 × 10^{−6} lbf |
≈ 7.2330 × 10^{−5} pdl |

1 kp | = 9.80665 N | = 980665 dyn | ≡ g_{n} ⋅ (1 kg) |
≈ 2.2046 lbf | ≈ 70.932 pdl |

1 lbf | ≈ 4.448222 N | ≈ 444822 dyn | ≈ 0.45359 kp | ≡ g_{n} ⋅ (1 lb) |
≈ 32.174 pdl |

1 pdl | ≈ 0.138255 N | ≈ 13825 dyn | ≈ 0.014098 kp | ≈ 0.031081 lbf | ≡ 1 lb⋅ft/s^{2} |

The value of g_{n} 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

- Thomson, Sir Wl; Professor GC, Foster; Maxwell, Professor JC; Stoney, Mr GJ; Professor Flemming, Jenkin; Siemens, Dr; Bramwell, Mr FJ (September 1873). Everett, Professor (ed.).
*First Report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units*. Forty-third Meeting of the British Association for the Advancement of Science. Bradford: Johna Murray. p. 223. Retrieved 8 April 2012. - Gyllenbok, Jan. "dyne".
*Encyclopaedia of Historical Metrology, Weights, and Measures, Volume 1*. Birkhäuser. p. 90. ISBN 9783319575988. Retrieved 20 April 2018. - "Dyne".
*The New Student's Reference Work*. Chicago: Compton. 1914. - Haynes, W.M.; Lide, D. R.; Bruno, T.J., eds. (2015). "Surface tension of common liquids".
*CRC Handbook of Chemistry and Physics*(96nd ed.). CRC Press. p. 6-181. ISBN 9781482260977.