begin mathsize 36px style P subscript i n end subscript equals P subscript o u t end subscript space plus space fraction numerator 2 gamma over denominator r end fraction end style

Pin = Pressure Inside the Curved Surface ; Pout = Pressure Outside the Curved Surface ; γ = Surface Tension ; r = Radious of Curvature of the Curved Surface ; 

 

Pin

Pout

γ

r

 
In order to minimize the surface area of a liquid, a formation of a curved suface occur. When vapous is trapped into thin film, it is called a bubble. However a cavity is a vapour filled hole in a liquid. Thus the bubbles that occur in a liquid is a cavity, and a soap bubble is a bubble. Thus a cavity has one surface and a bubble has two (one on each side of the film). The pressure on the concave side of an interface, is always greater than the pressure on the convex side. This is expressed by the above equation, which is known as the Young-Laplace equation.

Generate Citation