# Dyne

The **dyne** (symbol **dyn**, from Greek δύναμις, *dynamis*, meaning power, force) is a unit of force specified in the centimetre–gram–second system of units (CGS), a predecessor of the modern SI. One dyne is equal to 10^{−5}
N or to 10 nsn (nanosthenes) in the old metre–tonne–second system of units. Equivalently, the dyne is defined as "the force required to accelerate a mass of one gram at a rate of one centimetre per second squared":

- 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

The **dyne per centimetre** is the unit traditionally used to measure surface tension. For example, the surface tension of distilled water is 72 dyn/cm at 25 °C (77 °F);^{[1]} in SI units this is ×10^{−3} N/m or 72 mN/m. 72

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 lb_{F} |
≈ 7.2330 pdl |

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

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

1 lb_{F} |
≈ 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 lb_{F} |
≡ 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. |

## History

The names **dyne** and erg were first proposed as units of force and energy in 1861 by Joseph David Everett.^{[2]} The natural units listed in the same text (see Farad in this reference), are those of the metre-gram-second amu.

The names were reused in 1873 by a Committee of the British Association^{[3]} (of which Everett was reporter) that proposed using the centimetre-gram-second system for electrical and dynamical systems.

## References

- ↑
- ↑ Rossiter, William (1879).
*Dictionary of Scientific Terms*. London and Glasgow: William Collins, Sons, and Coy. p. 109. - ↑ Thomson, Sir W; 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.

Wikisource has the text of The New Student's Reference Work article .Dyne |