of densities of water and mercury (at a given temperature). Note that as long as this condition is satisfied (pressure greater than zero), the flow at the output of the siphon is still only governed by the height difference between the source surface and the outlet. Volume of fluid in the apparatus is not relevant as long as the pressure head remains above zero in every section. Because pressure drops when velocity is increased, a static siphon (or manometer) can have a slightly higher height than a flowing siphon.
|This section requires expansion with: explanation of theory of operation. (December 2012)|
Experiments have shown that siphons can operate in a vacuum, via cohesion and tensile strength between molecules, provided that the liquids are pure and degassed and surfaces are very clean.
Oxford English Dictionary
The Oxford English Dictionary (OED) entry on siphon, published in 1911, states that a siphon works by atmospheric pressure. Stephen Hughes of Queensland University of Technology criticized this in a 2010 article which was widely reported in the media. The OED editors stated, "there is continuing debate among scientists as to which view is correct. ... We would expect to reflect this debate in the fully updated entry for siphon, due to be published later this year." Dr. Hughes continued to defend his view of the siphon in a late September post at the Oxford blog. The 2015 definition by the OED is:
A tube used to convey liquid upwards from a reservoir and then down to a lower level of its own accord. Once the liquid has been forced into the tube, typically by suction or immersion, flow continues unaided.
The Encyclopædia Britannica currently describes a siphon as:
Siphon, also spelled syphon, instrument, usually in the form of a tube bent to form two legs of unequal length, for conveying liquid over the edge of a vessel and delivering it at a lower level. Siphons may be of any size. The action depends upon the influence of gravity (not, as sometimes thought, on the difference in atmospheric pressure; a siphon will work in a vacuum) and upon the cohesive forces that prevent the columns of liquid in the legs of the siphon from breaking under their own weight. At sea level, water can be lifted a little more than 10 metres (33 feet) by a siphon. In civil engineering, pipelines called inverted siphons are used to carry sewage or stormwater under streams, highway cuts, or other depressions in the ground. In an inverted siphon the liquid completely fills the pipe and flows under pressure, as opposed to the open-channel gravity flow that occurs in most sanitary or storm sewers.
|Wikimedia Commons has media related to Siphons.|
- 1992 Guadalajara explosions for details of an accident where a plumbing method Trap (plumbing) also known as a inverted siphon was partially responsible for gas explosions.
- Communicating vessels
- Gravity feed
- Jiggle syphon
- Marot jar
- Minor, Ralph Smith (1914). "Would a Siphon Flow in a Vacuum! Experimental Answers" (PDF). School Science and Mathematics. 14,2 (2): 152–155. doi:10.1111/j.1949-8594.1914.tb16014.x.
- "Video Demonstration of Siphon in Vacuum".
- Nokes M C 1948 "Vacuum siphons" School Science Review 29 233
- Siphon Concepts
- http://www.youtube.com/watch?v=sz9eddGw8vg Siphoning water to 24 meters
- https://www.youtube.com/watch?v=6ukMId5fIi0 Bead Chain Siphon
- https://www.youtube.com/watch?v=FWybQPxKy1U CO2 Gas Siphon
- Dora P. Crouch (1993). "Water management in ancient Greek cities". Oxford University Press US. p. 119. ISBN 0-19-507280-4
- Banu Musa (authors), Donald Routledge Hill (translator) (1979). The book of ingenious devices (Kitāb al-ḥiyal). Springer. p. 21. ISBN 90-277-0833-9.
- (Calvert 2000, "Maximum height to which water can be raised by a suction pump")
- Richert, Alex; Binder, P.-M. (February 2011). "Siphons, Revisited" (PDF). The Physics Teacher 49 (2): 78. Bibcode:2011PhTea..49...78R. doi:10.1119/1.3543576, press release: Yanking the chain on siphon claims, University of Hawaiʻi at Hilo, 19 January 2011
- "The Great Siphon Definition Debate". Retrieved 20