Dyne

For people with the name, see Dyne (name).

The dyne (symbol: dyn; from Ancient Greek 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.

dyne
Ohaus spring scale displaying force measurements in both newtons and dynes
General information
Unit system	CGS units
Unit of	force
Symbol	dyn
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

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

Units of force

v t e	newton	dyne	kilogram-force, kilopond	pound-force	poundal
1 N	≡ 1 kg⋅m/s2	= 105 dyn	≈ 0.10197 kp	≈ 0.22481 lbF	≈ 7.2330 pdl
1 dyn	= 10−5 N	≡ 1 g⋅cm/s2	≈ 1.0197×10−6 kp	≈ 2.2481×10−6 lbF	≈ 7.2330×10−5 pdl
1 kp	= 9.80665 N	= 980665 dyn	≡ gn × 1 kg	≈ 2.2046 lbF	≈ 70.932 pdl
1 lbF	≈ 4.448222 N	≈ 444822 dyn	≈ 0.45359 kp	≡ gn × 1 lb	≈ 32.174 pdl
1 pdl	≈ 0.138255 N	≈ 13825 dyn	≈ 0.014098 kp	≈ 0.031081 lbF	≡ 1 lb⋅ft/s2
The value of gn (9.80665 m/s2) 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.)

See also

• Centimetre–gram–second system of units
• Erg