Thunder

From Wikipedia, the free encyclopedia

Template:Short description Template:Hatnote group Lua error in package.lua at line 80: module 'Module:If preview' not found. Thunder is the sound caused by lightning.[1][2][3] Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning produces rapid expansion of the air in the path of a lightning bolt.[4] In turn, this expansion of air creates a sonic shock wave, often referred to as a "thunderclap" or "peal of thunder". The scientific study of thunder is known as brontology and the irrational fear (phobia) of thunder is called brontophobia.

Etymology

The d in Modern English thunder (from earlier Old English Script error: No such module "Lang".) is epenthetic, and is now found as well in Modern Dutch Script error: No such module "Lang". (cf. Middle Dutch donre; also Old Norse Script error: No such module "Lang"., Old Frisian þuner, Old High German Script error: No such module "Lang"., all ultimately descended from Proto-Germanic Script error: No such module "Lang".). In Latin the term was Script error: No such module "Lang". "to thunder". The name of the Nordic god Thor comes from the Old Norse word for thunder.[5]

The shared Proto-Indo-European root is Template:Wikt-lang, also found in Gaulish Taranis.[6]

Cause

The cause of thunder has been the subject of centuries of speculation and scientific inquiry.[7] Early thinking was that it was made by deities. Throughout the centuries, folklore has offered various fanciful explanations for what causes thunder, such as gnomes playing ninepins. Some of these were tongue-in-cheek humorous stories to tell young children so as to soothe their fear of the noise. The ancient Greek philosophers attributed it to natural causes, such as wind striking clouds (Anaximander, Aristotle) and movement of air within clouds (Democritus).[8] The Roman philosopher Lucretius held it was from the sound of hail colliding within clouds.[8] By the mid-19th century, the accepted theory was that lightning produced a vacuum and that the collapse of that vacuum produced what is known as thunder.[7]


Scientists have agreed since the 20th century that thunder must begin with a shock wave in the air due to the sudden thermal expansion of the plasma in the lightning channel.[9][8] The temperature inside the lightning channel, measured by spectral analysis, varies during its 50 μs existence, rising sharply from an initial temperature of about 20,000 K (19,700 °C; 35,500 °F) to about 30,000 K (29,700 °C; 53,500 °F), then dropping away gradually to about 10,000 K (9,700 °C; 17,500 °F). The average is about 20,400 K (20,100 °C; 36,300 °F).[10] This heating causes a rapid outward expansion, impacting the surrounding cooler air at a speed faster than sound would otherwise travel. The resultant outward-moving pulse is a shock wave,[11] similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft. Near the source, the sound pressure level of thunder is usually 165 to 180 dB, but can exceed 200 dB in some cases.[12]

Experimental studies of simulated lightning have produced results largely consistent with this model, though there is continued debate about the precise physical mechanisms of the process.[13][9] Other causes have also been proposed, relying on electrodynamic effects of the enormous current acting on the plasma in the bolt of lightning.[14]

Consequences

The shock wave in thunder is sufficient to cause property damage[7] and injury, such as internal contusion, to individuals nearby.[15] Thunder can rupture the eardrums of people nearby, leading to permanently impaired hearing.[7] Even if not, it can lead to temporary deafness.[7]

Types

Vavrek et al. (n.d.) reported that the sounds of thunder fall into categories based on loudness, duration, and pitch.[7] Claps are loud sounds lasting 0.2 to 2 seconds and containing higher pitches. Peals are sounds changing in loudness and pitch. Rolls are irregular mixtures of loudness and pitches. Rumbles are less loud, last for longer (up to more than 30 seconds), and are of low pitch.[16]

Inversion thunder results when lightning strikes occur between the cloud and ground during a temperature inversion. The resulting thunder sounds have significantly greater acoustic energy than those produced from the same distance in non-inversion conditions. In a temperature inversion, the air near the ground is cooler than the air higher up. Inversions often happen when warm, moist air passes above a cold front. Within a temperature inversion, sound energy is prevented from dispersing vertically as it would in non-inversion conditions, and is thus concentrated in the near-ground layer.[17]

Cloud-to-ground lightning (CG) typically consists of two or more return strokes, from ground to cloud. Later return strokes have greater acoustic energy than the first.[18]

Perception

Lua error in package.lua at line 80: module 'Module:If preview' not found.

The most noticeable aspect of lightning and thunder is that the lightning is seen before the thunder is heard. This is a consequence of the speed of light being much greater than the speed of sound. The speed of sound in dry air is approximately 343 metres per second (1,130 ft/s) or 667 knots (1,235 km/h; 768 mph) at 293 K (20 °C; 68 °F).[19]

This translates to approximately three seconds per kilometre (4.8 s/mi); saying "one thousand and one... one thousand and two..." is a useful method of counting the seconds from the perception of a given lightning flash to the perception of its thunder (which can be used to gauge the proximity of lightning for the sake of safety). To estimate the distance from the lightning strike, divide the counted seconds by five for miles,[20] or three for kilometers.

A very bright flash of lightning and an almost simultaneous sharp "crack" of thunder, a thundercrack, therefore indicates that the lightning strike was very near.

Close-in lightning has been described first as a clicking or cloth-tearing sound, then a cannon shot sound or loud crack/snap, followed by continuous rumbling.[7] The early sounds are from the leader parts of lightning, then the near parts of the return stroke, then the distant parts of the return stroke.[7]

See also

References

Page Template:Reflist/styles.css has no content.

  1. ^ Page Module:Citation/CS1/styles.css has no content."Severe Weather 101: Lightning Basics". nssl.noaa.gov. Retrieved October 23, 2019.
  2. ^ Page Module:Citation/CS1/styles.css has no content."Thunder Facts". factsjustforkids.com. Retrieved October 23, 2019.
  3. ^ Page Module:Citation/CS1/styles.css has no content."The Sound of Thunder". weather.gov. Retrieved October 23, 2019.
  4. ^ Page Module:Citation/CS1/styles.css has no content."What Causes Lightning and Thunder?". NOAA. 2022.
  5. ^ Page Module:Citation/CS1/styles.css has no content."thunder". Oxford English Dictionary (2 ed.). Oxford, England: Oxford University Press. 1989.
  6. ^ Matasovic, Ranko. Etymological Dictionary of Proto Celtic. Leiden, The Netherlands: Brill. 2009. p. 384. Template:ISBN
  7. ^ a b c d e f g h Page Module:Citation/CS1/styles.css has no content.Vavrek, R. J.; Kithil, R.; Holle, R. L.; Allsopp, J.; Cooper, M. A. (17 July 2006) [4 April 2006]. "Section 6.1.8: The Science of Thunder". National Lightning Safety Institute. Archived from the original on 17 July 2006. Retrieved 11 June 2022.
  8. ^ a b c Page Module:Citation/CS1/styles.css has no content.Heidorn, Keith C. (1999). "Thunder: Voice of the heavens". Archived from the original on 1999-10-23.
  9. ^ a b Page Module:Citation/CS1/styles.css has no content.Rakov, Vladimir A.; Uman, Martin A. (2007). Lightning: Physics and Effects. Cambridge, England: Cambridge University Press. p. 378. ISBN 978-0-521-03541-5.,
  10. ^ Page Module:Citation/CS1/styles.css has no content.Cooray, Vernon (2003). The lightning flash. London: Institution of Electrical Engineers. pp. 163–164. ISBN 978-0-85296-780-5.
  11. ^ Page Module:Citation/CS1/styles.css has no content."Thunder". Encyclopædia Britannica. Archived from the original on 2008-06-07. Retrieved 2008-09-12.
  12. ^ Page Module:Citation/CS1/styles.css has no content."Ultimate Sound Pressure Level Decibel Table". Retrieved 2020-12-13.
  13. ^ Page Module:Citation/CS1/styles.css has no content.MacGorman, Donald R.; Rust, W. David (1998). The Electrical Nature of Storms. Oxford University Press. pp. 102–104. ISBN 978-0195073379. Archived from the original on 2014-06-28. Retrieved 2012-09-06.
  14. ^ Page Module:Citation/CS1/styles.css has no content.P Graneau (1989). "The cause of thunder". J. Phys. D: Appl. Phys. 22 (8): 1083–1094. Bibcode:1989JPhD...22.1083G. doi:10.1088/0022-3727/22/8/012. S2CID 250836715.
  15. ^ Page Module:Citation/CS1/styles.css has no content.Fish, Raymond M (2021). "Thermal and mechanical shock wave injury". In Nabours, Robert E (ed.). Electrical injuries: engineering, medical, and legal aspects. Tucson, AZ: Lawyers & Judges Publishing. p. 220. ISBN 978-1-930056-71-8.
  16. ^ Page Module:Citation/CS1/styles.css has no content."Thunder Facts". Fast Facts for Kids. 2022.
  17. ^ Page Module:Citation/CS1/styles.css has no content.Dean A. Pollet and Micheal M. Kordich (2013-04-08). "User's guide for the Sound Intensity Prediction System (SIPS) as installed at the Naval Explosive Ordnance Disposal Technology Division (Naveodtechdiv)" (PDF). Systems Department February 2000. dtic.mil. Archived from the original on April 8, 2013.
  18. ^ Page Module:Citation/CS1/styles.css has no content."Lightning Types". NOAA National Severe Storms Laboratory. 2022.
  19. ^ Page Module:Citation/CS1/styles.css has no content.Handbook of Chemistry and Physics, 72nd edition, special student edition. Boca Raton: The Chemical Rubber Co. 1991. p. 14.36. ISBN 978-0-8493-0486-6.
  20. ^ Page Module:Citation/CS1/styles.css has no content."Understanding Lightning: Thunder". National Weather Service. 2022.

Page Module:Side box/styles.css has no content.Page Template:Sister project/styles.css has no content.

Page Template:Plainlist/styles.css has no content.
Script error: No such module "Sister project logo".
Wikimedia Commons has media related to Thunder.Template:Preview warning

Page Module:Side box/styles.css has no content.Page Template:Sister project/styles.css has no content.

Page Template:Plainlist/styles.css has no content.
Script error: No such module "Sister project logo".
Wikiquote has quotations related to Thunder.

Page Module:Side box/styles.css has no content.Page Template:Sister project/styles.css has no content.

Page Template:Plainlist/styles.css has no content.
Script error: No such module "Sister project logo".
Wikibooks has a book on the topic of: Engineering Acoustics/Thunder acoustics

Lua error in package.lua at line 80: module 'Module:Authority control/config' not found.

Retrieved from "https://cosmopedia.co/index.php?title=Thunder&oldid=63174"