Feynman sprinkler

A Feynman Sprinkler, Feynman inverse sprinkler or most correctly reverse sprinkler began as a thought experiment in explaining the workings of the reverse of a typical rotary lawn sprinkler. This experiment is commonly associated with and named after Richard Feynman though he did not come up with the problem or ever publish a solution to it, only helped popularize it in "Surely You're Joking, Mr. Feynman!" and other writings of his. [Jenkins, Alejandro. "California Institute of Technology". May 3, 2004. [http://www.citebase.org/cgi-bin/fulltext?format=application/pdf&identifier=oai:arXiv.org:physics/0312087 An elementary treatment of the reverse sprinkler] . Retrieved April 5, 2006.] It appeared in "Science of Mechanics" by Ernst Mach, published in 1893.cite book | title=Don't you have time to think? | first=Richard | last=Feynman | editor=Michelle Feynman | publisher=Penguin Books | year=2005 | isbn=978-0-141-02113-3 | pages=211]

Explanation

The problem concerns what would happen if such a lawn sprinkler were submerged in water and water were sucked through it, flowing backwards. The possible outcomes are as follows:" the sprinkler will spin forward; the sprinkler will spin backward; the sprinkler will not spin at all". There has been much debate in the past century over the solution [Calvert, J. B. September 28, 2004. [http://www.du.edu/~jcalvert/tech/fluids/turbine.htm Turbines] . Retrieved April 5, 2006.] . Feynman once attempted the experiment, "which ended in a minor catastrophic explosion". In recent years, the experiment has been performed many times, with air as the medium of the sprinkler, demonstrating that the "reverse" sprinkler does spin in the steady state [ [http://www.fotuva.org/online/frameload.htm?/online/sprinkler.html Richard Feynman's Water Sprinkler Experiment] , Feynman Online] . The University of Maryland also did the experiment on a very low friction bearing underwater and found that the sprinkler did indeed turn very slowly as if being sucked forwards. [ [http://www.physics.umd.edu/lecdem/outreach/QOTW/arch4/q061.htm The Physics Question of the Week #61] , The University of Maryland Department of Physics] Although many experiments have been done, the scientific community still debates the validity of them because of the complex forces involved.

References

External links

* [http://web.mit.edu/Edgerton/www/FeynmanSprinkler.html The Edgerton Center Corridor Lab: Feynman Sprinkler]