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Kilo naming confusion

  1. Oct 12, 2011 #1
    Hi guys,

    Got a question on the naming of the kilo unit.

    Lets say ive got a battery at 1 kWh capacity, the k is lower case. However MWh, mega is capitalised, so is GWh, TWh.

    Now on the other end of the scale i can understand it is lower case, mWh, μWh, nWh. And for the large end of the scale, the symbols are upper case, except for kilo.

    So why is it not KW instead of kW?
  2. jcsd
  3. Oct 12, 2011 #2
    I don't know for sure, it could be one of various reasons, including natural evolution.

    It could be that kilo pre-dates the standardization of the entire set of prefixes by many years of usage and they did not want to change 'k' when they put together the entire set.

    By the way, kilo is not the only lower case prefix on the 'larger' side of the scale, there is also 'h' hecto (x100) and 'da' deca (x10).

    And a kelvin is already upper case k, 'K'. Notice that a kelvin is not even a degree, it is just a kelvin; as opposed to farenheit and celsius, which are degrees.

    I think the whole point is to minimize confusion so that when you see a unit symbol you should be able to tell exactly what it is with minimal or no problem.

    I don't know if you know this, but regarding upper and lower case, there is something else you may want to know/be-aware-of...units named after the names of scientists also start with upper case:

    ...to list a few

    and when you write such units, they need to be written out in lower case, after all, they refer to the unit and not the scientist him/her-self. For example, 25W is written out 25 watts, not 25 Watts

    Hope this helps.
  4. Oct 12, 2011 #3


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    Staff: Mentor

    As gsal mentions, "K" is used for Kelvin.

    Also, in computer science, K=1024, which is not to be confused with k=1000.
  5. Oct 12, 2011 #4
    Interesting, thanks guys.

    However I don't see it common that one would use kilo with kelvin, 10 kK?
  6. Oct 14, 2011 #5
    Once you get to kiloKelvins, I think you're better off using eV.

  7. Oct 14, 2011 #6


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    Gold Member

    That's a nasty stutter you have there, but the observation is neat. :biggrin:
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