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Universal Mountain/Sea Thermometer

  1. Nov 17, 2005 #1
    Taking the definition we have in Europe (I don't know the US version of it) of temperature (we use Celsius Degree here most of the time) : 0° is defined as the triple point of water, and 100° the boiling point. Then I suppose it is usual to make a linear approx (dilatation is linear in first approx)..but then this should give altitude dependent thermometer ??
     
  2. jcsd
  3. Nov 18, 2005 #2

    Danger

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    I'm not quite sure that I understand your question. The 0 and 100 degrees C. are established at standard pressure. While water will boil at less than 100* at high altitude, the thermometer won't change to show it as 100*. (Damn, I wish this PC had a degree sign. :grumpy: )
     
  4. Nov 18, 2005 #3

    FredGarvin

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    alt+0176 Danger...


    °°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°
     
  5. Nov 18, 2005 #4

    Danger

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    Now I'm even more baffled, Fred. I tried what you said, and as soon as I entered alt017 PF closed and kicked me back to IE. Never even had a chance to hit 6. :confused:
     
  6. Nov 18, 2005 #5

    FredGarvin

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    You have to use the numbers on the number key pad, not the ones near the QWERTY. I If I try to do it on my laptop, it does the same thing.
     
  7. Nov 18, 2005 #6
    high temperature adversely affect PC working. But does pressure affect?
     
  8. Nov 18, 2005 #7

    Danger

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    Thanks, Fred. I'm still not used to stupid PC's, and the NumLock on this one wasn't engaged. Macs don't have keypads. °°° :smile:
     
  9. Nov 18, 2005 #8
    Yes, I think there is a lack in this defintion, we don't say the amount of impurities (ions, or isotopes of water), which makes verxy precise building of thermometer not easy...By the way, does somebody know where the convention T=25°C and P=1025hPa comes from...or it other convention in other countries (in fact i don't even know the European one)....
     
  10. Nov 19, 2005 #9

    Bystander

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    Can't tell you what this week's IUPAC-IUPAP conventions are, but the b.p. got scrapped long time ago.
    The Kelvin scale is defined by absolute zero and the triple point of water. The Kelvin is 1/273.16 of the temperature difference between the triple point of "Vienna Water" (?), don't quote me on "Vienna," and absolute zero. Takes care of the composition question, and of pressure. b.p. of water at one atmosphere is 99.xyz oC, and 0 oC is still 273.15 K.
    Help any?
     
  11. Nov 20, 2005 #10
    (Yes, this is exactly the point, there is 1/100 per scaling unit difference between K and °C...??) But technically speaking, how to do calibrate a thermometer at 0K ?
     
  12. Nov 20, 2005 #11

    Mk

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    Of course if you were on a MACINTOSH computer you would just press option+k. K for Kelvin.
     
  13. Nov 21, 2005 #12

    Danger

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    Mk, you goof... it's Option-0 on my G3. :tongue:
    I also got one by accident once with a Command-Option-? combo.
     
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