|MLA Citation:||Bloomfield, Louis A. "Question 1002"|
How Everything Works 19 Jan 2018. 19 Jan 2018 <http://howeverythingworks.org/print1.php?QNum=1002>.
Because physical systems tend toward arrangements that minimize their overall potential energies, a liquid tends to minimize its surface area in order to minimize the number of high-energy molecules it has at its surface. This tendency to minimize surface area is the origin of surface tension in a liquid. The liquid behaves as though its surface were a taut elastic membrane. If you poke at a liquid, you can deform its surface but as soon as you stop pushing on it, it will spring back to its original flat or smoothly curved shape. That springiness is the result of surface tension.