Smokers may blow smoke rings from the mouth, intentionally or accidentally. Smoke rings may also be formed by sudden bursts of fire (such as lighting and immediately putting out a cigarette lighter), by shaking a smoke source (such as an incense stick) up and down, by firing certain types of artillery, or by the use of special devices, such as vortex ring toys. The head of a mushroom cloud is a large smoke ring.
A smoke ring is commonly formed when a puff of smoke is suddenly injected into clear air, especially through a narrow opening. The outer parts of the puff are slowed down by the still air (or by edges of the opening) relative to the central part, imparting it the characteristic poloidal flow pattern.
The smoke makes the ring visible, but does not significantly affect the flow. The same phenomenon occurs with any fluid, creating vortex rings which are invisible but otherwise entirely similar to smoke rings.
When blown in still air, a smoke ring usually travels roughly straight from the opening over a surprisingly large distance, maintaining its shape, until dispersed by turbulence or other interference.
Smoking and breathing
A smoker may create rings by taking smoke into his mouth and expelling it with a tongue flick, by closing the jaw, tapping the cheek, or producing a sudden burst of air with the lungs and throat. The smoker may also use any of those methods to blow into a cloud of smoke outside his mouth.
A trick often performed in conjunction with mouth-blown smoke rings is the French inhale.
It is also possible to create a vapour ring by using the same techniques on a cold day with only one's breath.
Under particular conditions, some volcanic vents can produce large visible smoke rings. Though a rare phenomenon, several volcanoes have been observed emitting massive vortex rings of steam and gas:
- Mount Etna, Italy (Sicily)
- Stromboli, Italy (Aeolian Islands)
- Eyjafjallajökull, Iceland
- Hekla, Iceland
- Tungurahua, Ecuador
- Pacaya, Guatemala
- Mount Redoubt, USA (Alaska)
- Mount Aso, Japan (Kyushu)
- Whakaari (White Island), New Zealand
- http://www.volcanodiscovery.com/photoglossary/smoke_ring.html Illustrated Volcano Glossary
- Etna hoops it up BBC News, 2003-03-31.
- Etna 2000 Stromboli Online, 2009-03-12.
- http://video.it.msn.com/watch/video/miracolo-etna-dal-cratere-anelli-di-fumo-perfetti/168go5fdp Smoke rings of Mount Etna video
- Iceland Volcano Blows Spectacular Smoke Ring: Big Pics Discovery News, 2010-05-10.
|This article needs additional citations for verification. (December 2011)|
- How to puff a smoke ring?
- Blowing a smoke ring (wikiHow)
- Smoke rings generated by eruptions of Etna volcano
- Smoke rings from Stromboli volcano
- Instructions on building a smoke ring cannon
- Smoke rings at US Army disposals in Iraq (see images on bottom)
- Thomson, Sir William (Lord Kelvin), On Vortex Atoms, Proceedings of the Royal Society of Edinburgh, Vol. VI, 1867, pp. 94–105.
- Silliman, Robert H., William Thomson: Smoke Rings and Nineteenth-Century Atomism, Isis, Vol. 54, No. 4. (Dec., 1963), pp. 461–474. JSTOR link
- Movie of a modern recreation of Tait's smoke ring experiment
- How to Blow Smoke Rings - Howiw