The Machine
The device consists of a gear known as a ratchet that rotates freely in one direction but is prevented from rotating in the opposite direction by a pawl. The ratchet is connected by an axle to a paddle wheel that is immersed in a fluid of molecules at temperature . The molecules constitute a heat bath in that they undergo random Brownian motion with a mean kinetic energy that is determined by the temperature. The device is imagined as being small enough that the impulse from a single molecular collision can turn the paddle. Although such collisions would tend to turn the rod in either direction with equal probability, the pawl allows the ratchet to rotate in one direction only. The net effect of many such random collisions should be sufficient for the ratchet to rotate continuously in that direction. The ratchet's motion then can be used to do work on other systems, for example lifting a weight (m) against gravity. The energy necessary to do this work apparently would come from the heat bath, without any heat gradient. Were such a machine to work successfully, its operation would violate the second law of thermodynamics, one form of which states: "It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work."
Read more about this topic: Brownian Ratchet
Famous quotes containing the word machine:
“I find it hard to believe that the machine would go into the creative artist’s hand even were that magic hand in true place. It has been too far exploited by industrialism and science at expense to art and true religion.”
—Frank Lloyd Wright (1869–1959)
“The chrysanthemums’ astringent fragrance comes
Each year to disguise the clanking mechanism
Of machine within machine within machine.”
—Wallace Stevens (1879–1955)