Capitalizing Unit Abbreviations
Date: 09/15/2003 at 12:11:38 From: Ricky Subject: Metric Measurement Why do we use a lowercase m to abbreviate meters, but an uppercase L to abbreviate liters? Actually, I've always seen both used either way. Which is right? Or are they both right?
Date: 09/15/2003 at 15:22:54 From: Doctor Peterson Subject: Re: Metric Measurement Hi, Ricky. The m is always lower case, but the L may be either. See this page: http://www.unc.edu/~rowlett/units/dictL.html liter or litre (L or l) the common metric unit of volume. ... Both the lower case letter l and the upper case L are accepted as symbols for the liter, but the U.S. Department of Commerce specifies that L be used, at least by businesses, to avoid confusion with the numeral 1. The unit is spelled liter in the U.S. and litre in Britain; there are many other spellings in various languages (see Spelling of Metric Units). This page gives the general rule: http://ts.nist.gov/ts/htdocs/200/202/metrsty3.htm Capitals Units: The names of all units start with a lower case letter except, of course, at the beginning of the sentence. There is one exception: in "degree Celsius" (symbol °C) the unit "degree" is lower case but the modifier "Celsius" is capitalized. Thus, body temperature is written as 37 degrees Celsius. Symbols: Unit symbols are written in lower case letters except for liter and those units derived from the name of a person (m for meter, but W for watt, Pa for pascal, etc.). Prefixes: Symbols of prefixes that mean a million or more are capitalized and those less than a million are lower case (M for mega (millions), m for milli (thousandths)). There is some variation in preference between countries: http://lamar.colostate.edu/~hillger/correct.htm The symbol for liter (or litre) may be either a capital el (L) or a lowercase el (l); both are correct. In the U.S., Canada, and Australia, the capital el (L) is preferred, but most other nations use the lowercase el (l). This gives a nice explanation for Liter: http://www.metricamerica.com/symbols.htm Please Note: Where symbols are used convention has it that they are always lower case letters except where the Base Unit is named after a person like Celsius (°C), Pascal (P) or Newton (N). Then the symbol is noted by a CAPITAL LETTER. So what's with a capital letter "L" for liter? Is that a capital "L" for the unit of measure named after a person? No.... You see, when decimal dimensions were described long before the typewriter you would have to write the script "l". But as technology came along it became apparent that typewriters were not equipped with the script "l" so attempts were made to use the lower case "l" (el). Then it became further confusing to write "1l" (lower case "el") as the "1" and "l" (el) looked too similar as did the capital "I" (eye). So the capital "L" was chosen as the symbol for the derived base unit "liter". If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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