The Lippman-Young equation states that the change in contact angle of a drop on a substrate is also proportional to one over this quantity.  
The Ohnesorge number divides the viscosity by the square root of the product of length, density, and this quantity; the Weber number is proportional to one over it.  The Lippman-Young equation states that the change in contact angle of a drop on a substrate is also proportional to one over this quantity.  Dipalmitoyl phosphatidylcholine and sodium dodecyl sulfate both reduce this quantity, which is a result of cohesive forces among molecules of liquid.  Often denoted with a lowercase gamma and expressed in newtons per meter, for 10 points, name this property of liquids which can be reduced by surfactants and allows small insects to walk on water.
The Ohnesorge number divides the viscosity by the square root of the product of length, density, and this quantity; the Weber number is proportional to one over it.  
{surface tension}