Editing Surface tension (section)

===Breakup of streams into drops===
[[File:Dripping faucet 2.jpg|thumb|upright|Breakup of an elongated stream of water into droplets due to surface tension.]]

{{Main|Plateau–Rayleigh instability}}
In day-to-day life all of us observe that a stream of water emerging from a faucet will break up into droplets, no matter how smoothly the stream is emitted from the faucet. This is due to a phenomenon called the [[Plateau–Rayleigh instability]],<ref name="cwp"/> which is entirely a consequence of the effects of surface tension.

The explanation of this instability begins with the existence of tiny perturbations in the stream. These are always present, no matter how smooth the stream is. If the perturbations are resolved into [[Sine wave|sinusoidal]] components, we find that some components grow with time while others decay with time. Among those that grow with time, some grow at faster rates than others. Whether a component decays or grows, and how fast it grows is entirely a function of its wave number (a measure of how many peaks and troughs per centimeter) and the radii of the original cylindrical stream.