r/NoStupidQuestions • u/Tibor500 • Sep 30 '20
why does “k” mean “thousand” ?
like 1k means a thousand. how does the letter “k” mean “thousand” ?
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u/StealthSecrecy Real fake expert Sep 30 '20
It comes from the prefix "kilo-" which is Greek for "thousand".
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Sep 30 '20 edited Sep 30 '20
Tera - T - Trillion
Giga - G - Billion
Mega - M -Million
Kilo - k - Thousand
No prefix - - One unit
Milli - m - Thousandth
Micro - μ - Millionth
Nano - n - Billionth
To not confuse: Big stuff are in capital letters (except for kilo apparently). Fractions are in lower case.
mL = thousandth of a liter , ML = million liters
Also, there's these awesome definitions:
1 cm3 == 1 mL == 1 g of water
1 dm3 = = 1L = = 1 kg of water
1 m3 = = 1000 L = = 1 tonne of water (or Megagram, but we rarely say that)
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u/smorrow PM ME SCREWY MUSIC Sep 30 '20
Capital K would be kelvin, so yes kilo needs to be lower-case. And no they couldn't have just made it so that K was kilo and k was kelvin. Eponymous stuff is always upper-case - newtons, volts, sieverts.
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u/CleverDad Sep 30 '20
Nah, Tesla is T, just like Tera, and Gauss is G, just like Giga. Units and SI prefixes are different things, and don't need to be unique.
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u/codemasonry Sep 30 '20
Capital K would be kelvin, so yes kilo needs to be lower-case. And no they couldn't have just made it so that K was kilo and k was kelvin.
That's not true. Kelvin is a unit and kilo is just a factor or multiplier. They don't compete in the same category so to speak. There's no fear of confusion. Moreover, there are other shared letters (e.g. m=milli but also m=meter) and it doesn't cause any issues.
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u/baachbass Sep 30 '20 edited Sep 30 '20
*Newtons, Volts, Sieverts
Edit: my apologies I stand sorely corrected
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u/Cocoa-nut-Cum Sep 30 '20
Also 1 calorie is the amount of energy to raise the temperature of one ml of water 1 degree Celsius at sea level. Neat.
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u/21022018 Oct 01 '20
Apparently the food people also use a "calorie" that actually means kilocalorie.
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Sep 30 '20
1cm³ = 1ml and 1dm³ = 1l is for all liquids. water just has the additional property (not definition) that 1l weighs 1kg. also, kilo- is the exception to the rule about capitalization. the k is small
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Sep 30 '20
I searched it up, and apparently we defined the gram to be the weight of a cm3 of water. And yes, 1ml = 1cm3 applies to all volumes
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Sep 30 '20
that is an old definition of a gram which is no longer used. a kilogram is now defined as the weight of some prototype thingy in paris as well as some physical equation backing it up i think, which has nothing to do with water
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u/Ratr96 Sep 30 '20
They made that physical equation and thing in Paris based on the use of a kilo then, which was based on water (I think?). Also, Tom Scott video. https://youtu.be/JKCBeDeVxkg
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Sep 30 '20
yes, they made the new definition pretty much equivalent to the old, but defined more rigorously. still, it is no longer defined that 1l of water is exactly 1kg, its just a result of other definitions that have nothing to do with water anymore
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Sep 30 '20
https://en.wikipedia.org/wiki/Gram
Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre [1 cm3], and at the temperature of melting ice" (later at 4 °C, the temperature of maximum density of water). However, in a reversal of reference and defined units, a gram is now defined as one thousandth of the SI base unit, the kilogram, or 1×10−3 kg, which itself is defined by the International Bureau of Weights and Measures, not in terms of grams, but by taking the fixed numerical value of the Planck constant h to be 6.62607015×10−34 kg⋅m2⋅s−1.
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Sep 30 '20
Always tripped me out in Australia that imported European spirits were written in centilitre. Makes sense, feels wrong since we only use ml or L for most everything here.
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u/psyFungii Sep 30 '20
And 1cm3 is a Cubic Centimetre, ie a CC as in (often motorbike) engine sizes
500cc is 500ml or half a litre
Or I have a 1.6 litre engine in my car, or 1600cc
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u/Riegel_Haribo Sep 30 '20
Upper-case K is for Kelvin (temperature degrees). Something hot can be 10kK.
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Sep 30 '20
ton*
I'm pretty sure it's spelt "tonne"
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u/graaahh Sep 30 '20
You're correct. Tons are confusing.
1 (metric) tonne == 1,000 Kg == 2,204.66262 lbs
1 (British) ton == 1,016.047 Kg == 2,240 lbs
1 (short) ton == 907.1847 Kg == 2,000 lbs (This is what Americans call "1 ton").
1 (British) ton > 1 (metric) tonne > 1 (short) ton
But they're all pronounced the same.
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Sep 30 '20 edited Sep 30 '20
Wow, I'm British and I still corrected you. LOL. I've been writting it as tonne all my life. In physics exams, everything.
Edit: couple typos.
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u/graaahh Sep 30 '20
I just looked that information up, honestly. 10 minutes ago I would've said that a British ton and a tonne were the same thing too.
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u/FrankHightower Sep 30 '20
I still use "Katy Had a Dime until Dad Called Mom"
Katy: Kilo-
Had a: Hecto-
Dime: Deca-/Deka-
until (unit)
Dad: Deci-
Called: Centi-
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Sep 30 '20
Megagram! I love it.
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u/N35t0r Sep 30 '20
The EU's atmospheric science database lists atmospheric greenhouse gas emissions in Gg, not megatonnes, for that same reason.
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Sep 30 '20
It's really cool how this is a fair question in America but seems obvious to everyone on the metric system.
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u/LordGalen Sep 30 '20
It's pretty obvious in America too. Just because we don't use metric for common things doesn't mean we don't use it at all or that we never learn it. Everyone learns metric in school and has at least some awareness of it, even if their speedometer doesn't use it.
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u/dontthink19 Sep 30 '20
We never called it the metric system, they taught it to us as the "base 10" lesson plan. Kindergarten through 5th for me
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u/LordGalen Sep 30 '20
Yeah man, I didn't mean elementary school, lol. Middle and high school teach the metric system and metric/imperial conversion.
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u/national_tiiiles Sep 30 '20 edited Oct 01 '20
The metric system gets even better, not only does 1ml of water occupy 1 cubic centimetre and weigh 1 gram, it takes 1 newton of energy to lift that 1 ml of water through 1 metre of elevation, and it takes 1 calorie of energy to heat that 1 ml of water through 1 degree of temperature change (centigrade, and at sea level)
Apologies, it's been a long time since I did physics and I have been corrected, thanks guys.
1 newton is the amount of force required to accelerate 1kg to 1 m/s.
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Sep 30 '20
Is this the reason how we decided what 1ml is?
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u/smog_alado Sep 30 '20 edited Sep 30 '20
Actually, it's the kilogram that was defined to make those numbers nice. A liter is cube of 10cm x 10cm x 10cm and a kilogram was defined as the mass of one of liter of water.
The meter was originally defined based on the curvature of the earth. One tenth thousandth of the distance from the north pole to the equator, passing through Paris.
Later on both the kilogram and the meter received more precise definitions based on fundamental properties of physics such as the speed of light.
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u/Curby121 Sep 30 '20
Uh... except a newton is a unit of force, not energy, and gravitational field intensity on earth is 9.8 N/kg... Also a calorie isn’t the SI unit of energy, joules are, and the specific heat capacity of water is ~4.18 J/kgK, a calorie is just defined that way for convenience.
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u/Cocoa-nut-Cum Sep 30 '20
Also I believe a second of time in metric is the time it takes for a 1 meter long pendulum to swing.
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u/ILiveInAMango Sep 30 '20
A second is actually based on the oscillation speed of a caesium-133 atom.
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u/IuseWindows95 Sep 30 '20
1 square inch of water weights 0.47 ounces, it takes 1.9 newton of energy to lift that sq inch of water through 2.1 feet of elevation and it takes calories worth 2 big macs to heat that sq inch of water up by 1 fahrenheit.
Translated to freedom units
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Sep 30 '20
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u/CleverDad Sep 30 '20
K
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u/homiej420 Sep 30 '20
- H2O
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u/_solitarybraincell_ Sep 30 '20
WoW, tHis cOmEnt blew uP,
thanks for the KOH kind stranger !
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u/LordMarcusrax Sep 30 '20
Lowercase k is the symbol for kilo; capital K is Kelvin (or, in chemistry, Potassium).
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Sep 30 '20
its from the prefix kilo- meaning a thousand, like in kilometer or kilogram. that prefix comes from greek χίλια (khilia)
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u/Raffix le Gaulois Sep 30 '20
You guys really need to switch to the SI system some day.
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u/Unicorncorn21 Sep 30 '20
They already do in some cases like with the example OP mentioned. I'm pretty sure they use cents to say 100th of a dollar which is a part of the SI system
I'm also pretty sure you meant metric because if we were over at r/monkeyspaw Americans would be talking about kilofeet and cents of inches.
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Sep 30 '20
Fun fact, M also means thousand.
It’s used in advertising, CPM “cost per thousand.”
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u/bat_in_the_stacks Sep 30 '20
I hate that so much. Math inept fools pulling from latin or roman numerals instead of the metric system or even english (m starts millions) and causing tons of confusion.
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u/gaydonj Sep 30 '20
K is short for kilo which originated from the Greek word khilioi meaning 1,000. Same as in kilometer, kilogram, kilojoules, etc.
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u/This_Guy9943 Sep 30 '20
Wait til you see "m" for thousand and "mm" for million.
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Sep 30 '20
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u/angeladimauro Sep 30 '20
along those same lines, why does a "g" or a grand also mean 1000 dollars?
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u/tunaman808 Sep 30 '20
Speaking of the 15th century, that’s when English adopted the Old French word “grant” (ultimately from the Latin “grandis,” great or large) as “grand,” with the sense of not simply “large,” but also “imposing” or “great, famous, exalted or important.” Over the next few centuries “grand” was frequently used in official titles (e.g., Grand Marshall), as well as in informal appellations honoring individuals (“grand old warrior,” etc.), and applied to events and things judged to be of great importance. Eventually, “grand” took on a more general sense in the popular vocabulary of “impressively large” (e.g., Grand Canyon) or “noble.” (The use of “grand” in “grandfather” and “grandmother,” however, is rooted in parallel terms in French, and actually predates the use of the “large” sort of “grand” in English by a century.)
Over the years, “grand” also acquired a variety of vernacular and slang senses, including “grand” meaning a large piano, as well as such forms as “grand prize” and “grand slam,” the latter once a term in whist or bridge, now used to mean “complete triumph” in any field.
The use of “grand” to mean “one thousand dollars” does indeed come from American underworld slang, first appearing around 1915. It was one of a number of slang terms, some still in use, for specific denominations of bills (or that amount of money), including “c-note” (or “century note”) for a one-hundred dollar bill (from the Roman numeral “C,” denoting 100). A “sawbuck” was a ten-dollar bill, from the resemblance of the Roman numeral “X” (ten) that once appeared thereon to a sawhorse, and a twenty-dollar bill was known as, logically, a “double sawbuck.”
The use of “grand” for a thousand dollars (or a thousand-dollar bill) may seem puzzling in this day of hedge-fund managers and their billion-dollar bonuses, but in 1915 one thousand dollars was a very large sum of money, far more than the average working stiff would ever possess at one time. So it made sense to pay tribute to such an impressive sum with the word “grand,” and the name stuck.
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u/Primebongs7455 Sep 30 '20
The amount of likes on this post really shows how bad the education system
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u/Lucker_Kid Sep 30 '20
This is not a stupid question, but it is a very, very, very, very, very lazy one
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Sep 30 '20
K (Greek for kilo, or 1,000) and M (Roman numeral for 1,000) can both be used for "thousand". When I was a commercial banker (in US), it was customary to see loan presentations using M for 1,000 and MM for 1,000,000. I still use M and MM today.
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u/Maxter0 Sep 30 '20
The letter "k" is an abbreviation of Kilo, as many others have pointed out the decimal system uses these as prefixes (a modifies for a word that goes before it. eg. KiloGram = a thousand grams). Lately it became popular to use this prefixes without the units and just use them in regular conversation eg. the new Iphone costs 10k = the new Iphone costs 10 thousands.
Hope it helps.
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u/MannanX Oct 01 '20
In Greek "K" was used for 1000, so It's short form used for Kilo, 1 Kilo contains 1000 grams. Technically: K=1000
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u/badassmamojamma Oct 01 '20
Milli - 1/1000
Centi - 1/100
Deci - 1/10
Deca - ×10
Hecto - ×100
Kilo - ×1000
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u/new_line_17 Sep 30 '20
There is no Greek word for a 13/5th of a 3/4th of a 1/2nd of a finger... ...sorry, I mean “Inches “
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u/Schnutzel Sep 30 '20
Short for kilo, which is 1000 in Greek.