Suction cup

From Wikipedia, the free encyclopedia

A suction cup is a device, usually made of rubber or plastic, that sticks to smooth, nonporous surfaces. They are usually used to attach objects together with the use of suction.

Upon pressing the suction cup to a surface, the air pressure inside is drastically reduced. The relatively higher atmospheric pressure outside prevents the cup from lifting off the surface; friction does the rest of the work.

Suction cups are believed to have first been used in the 3rd century, B.C., and were made out of gourds. They were used to suction "bad blood" from internal organs to the surface. Hippocrates is believed to have invented this procedure. Suction cups are used on Nerf darts and can also be found on plungers. The U.S. Navy has used suction cups for several years to recover submarines sunk in enemy action.[1]

The modern suction cup was patented in 1882, and is based on the suction cup-like features on octopus arms. The patent has expired.

When calculating the amount of pressure that a suction cup has on an object: First, find the area of the suction cup using πr^2. Second, multiply the area by 14. (14 represents air pressure which is 14 pounds per square inch)