What is the diameter of human hair in CM?

A hair's breadth, or the width of human hair, is used as an informal unit of a very short length.[1] It connotes "a very small margin" or the narrowest degree in many contexts.[2][3][4][5][6][7]

Definitions[edit]

This measurement is not precise because human hair varies in diameter, ranging anywhere from 17 μm to 181 μm.[8] One nominal value often chosen is 75 μm,[5] but this – like other measures based upon such highly variable natural objects, including the barleycorn[9] – is subject to a fair degree of imprecision.[5][7]

Such measures can be found in many cultures. The English "hair's breadth"[6] has a direct analogue in the formal Burmese system of Long Measure. A "tshan khyee", the smallest unit in the system, is literally a "hair's breadth". 10 "tshan khyee" form a "hnan" (a Sesamum seed), 60 (6 hnan) form a mooyau (a species of grain), and 240 (4 mooyau) form an "atheet" (literally, a "finger's breadth").[10][11]

Some formal definitions even existed in English. In several systems of English Long Measure, a "hair's breadth" has a formal definition. Samuel Maunder's Treasury of Knowledge and Library of Reference, published in 1855, states that a "hair's breadth" is one 48th of an inch (and thus one 16th of a barleycorn).[12] John Lindley's An introduction to botany, published in 1839, and William Withering' An Arrangement of British Plants, published in 1818, states that a "hair's breadth" is one 12th of a line, which is one 144th of an inch or ~176 μm (a line itself being one 12th of an inch).[13][14]

Other body part measurements[edit]

Winning a competition, such as a horse race, "by a whisker" (a short beard hair) is a narrower margin of victory than winning "by a nose."[15][16] An even narrower anatomically-based margin might be described in the idiom "by the skin of my teeth," which is typically applied to a narrow escape from impending disaster. This is roughly analogous to the idiomatic phrase "as small as the hairs on a gnat's bollock."[17] German speakers similarly use “Muggeseggele,” literally “housefly’s scrotum,” as a small unit of measurement.[18]

See also[edit]

• Beard-second
• List of humorous units of measurement
• List of unusual units of measurement
• Indefinite and fictitious numbers

References[edit]

Notes[edit]

Citations[edit]

1. ^ "Hair's breadth (hare's breath)". Grammarist. Retrieved January 27, 2015.
2. ^ Hairs breadth. Oxford English Dictionary. Archived from the original on February 3, 2015. Retrieved January 28, 2015.
3. ^ "Hairs breadth". Macmillan English Dictionary. Retrieved January 27, 2015.
4. ^ "Hairs breadth". Cambridge Dictionary. Retrieved January 27, 2015.
5. ^ a b c Smith 2002, p. 253.
6. ^ a b Crook & Osmaston 1994, p. 133.
7. ^ a b Johnson 1842, pp. 1257.
8. ^ Ley, Brian (1999). Elert, Glenn (ed.). "Diameter of a human hair". The Physics Factbook. Retrieved 2018-12-08.
9. ^ Boaz, Tilloch & Taylor 1823, p. 267.
10. ^ Latter 1991, pp. 167.
11. ^ Carey 1814, p. 209.
12. ^ Maunder 1855, p. 12.
13. ^ Lindley 1839, p. 474.
14. ^ Withering 1818, p. 69.
15. ^ "Win by a nose". The American Heritage® Idioms Dictionary. Houghton Mifflin Company/Dictionary.com. 2002. Retrieved January 27, 2015.
16. ^ "By a nose". Free Dictionary. Retrieved December 30, 2016.
17. ^ "The meaning and origin of the expression: By the skin of your teeth". The phrase finder. Retrieved January 28, 2015.
18. ^ Sellner, Jan (9 March 2009). "Schönstes schwäbisches Wort: Großer Vorsprung für Schwabens kleinste Einheit". Stuttgarter Nachrichten (in German). Archived from the original on 27 September 2013. Retrieved 13 August 2013.

Sources[edit]

• Boaz, James; Tilloch, Alexander, Editor; Taylor, Richard, Editor (1823-03-21). "On a fixed Unit of Measure". Philosophical Magazine. Vol. 61. London: Richard Taylor. p. 267.
• Carey, Felix (1814). "Of Weights &c.". A grammar of the Burman language. Mission Press/Internet Archive. p. 209.
• Crook, John; Osmaston, Henry (1994). "Weights and Measures". Himalayan Buddhist Villages. Delhi: Shri Jainendra Press. p. 133. ISBN 978-0862923860.
• Dalzell, Tom; Victor, Terry, eds. (2013). The New Partridge Dictionary of Slang and Unconventional English. Routledge, Taylor & Francis Group. p. 1843. ISBN 9781317372523.
• Dickson, Paul (1994). War Slang: Fighting Words and Phrases of Americans from the Civil War to the Gulf War. Ann Arbor: University of Michigan Press. p. 286. ISBN 0-671-75022-4.
• Dickson, Paul (April 11, 2011). War Slang: American Fighting Words & Phrases Since the Civil War. p. 286. ISBN 9780486477503.
• Dorson, Richard Mercer (1986). Handbook of American Folklore. Bloomington, Indiana: Indiana University Press. p. 123. ISBN 0-253-20373-2.
• Hales, John (2005). Shooting Polaris a personal survey in the American West. Columbia, Missouri: University of Missouri Press. p. 45. ISBN 0-8262-1616-1.
• Jillette, Pen (2004). Sock: A Novel. p. 114. ISBN 1429961317.
• Johnson, Cuthbert William (1842). "Weights and Measures". The farmer's encyclopædia, and dictionary of rural affairs. London: Longman, Orme, Brown, Green, & Longmans/Internet Archive. p. 1257.
• Johnson, Sterling (1995). English as a Second f*cking Language. New York: Saint Martin's Press, St. Martin's Griffin. ISBN 978-0-312-14329-9.
• Latter, Thomas (1991). "Measures". A Grammar of the Language of Burmah (republished ed.). Asian Educational Services. p. 167. ISBN 9788120606937.
• Lindley, John (1839). "Glossology". An introduction to botany (3rd ed.). London: Longman, Orme, Brown, Green, & Longmans. p. 474.
• Maunder, Samuel (1855). "Measures of Length". Treasury of Knowledge and Library of Reference. New York: J. W. Bell. p. 12.\
• McYoung, Mark Animal (1991). Fists, Wits and a Wicked Right:Surviving on the Wild Side of the Street. Boulder, Colorado: Paladin Press. p. 25.
• Michaelis, David (1983). The best of friends: profiles of extraordinary friendships (Print). New York: Morrow. p. 231. ISBN 0-688-01558-1.
• Morton, Mark S. (2003). The lover's tongue a merry romp through the language of love and sex (Print). Toronto Ontario: Insomniac Press. p. 134. ISBN 1-894663-51-9.
• Partridge, Eric; Dalzell, Tom; Victor, Terry (2008). The Concise New Partridge Dictionary of Slang and Unconventional English (Print). London New York: Routledge. pp. 535, 1596 & 1601. ISBN 0-415-21259-6.
• Raudaskoski, Heikki (January 1997). 'The Feathery Rilke Mustaches and Porky Pig Tattoo on Stomach': High and Low Pressures in Gravity's Rainbow. Postmodern Culture. Vol. 7. Retrieved January 20, 2015.
• Smith, Graham T. (2002). Industrial metrology. Springer. pp. 253. ISBN 9781852335076.
• Spelvin, Georgina (2008). The Devil Made Me Do It (Print). Los Angeles, California: Lulu.com, Little Red Hen Books. p. 110. ISBN 0-615-19907-0.
• Withering, William (1818). "Botanical Terms". An Arrangement of British Plants. Vol. 1 (6th ed.). London: Longman & Co., Robert Scholey, et al. p. 69.

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