Jurin's law

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Capillary rise or fall in a tube.

Jurin's law describes the rise and fall of a liquid within a thin capillary tube. Named after its discoverer James Jurin.

This law is expressed as:

 \qquad h = \frac{2\gamma \cos\theta}{r\rho g}

where

  • h is the liquid height ;
  • γ is the liquid surface tension ;
  • θ is the contact angle of the liquid on the tube wall ;
  • ρ is the liquid density ;
  • r is the tube radius ;
  • g is the gravitational acceleration.

This law is valid if the tube radius is smaller than the capillary length.

See also[edit]