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Science Forum

  1. Subscriber ysterbaard
    AAPS forever
    25 Jan '10 21:25
    When the weather report say: " the humidity is 70% today, but tomorrow it should be 50%" Does it mean the 50% of the air is made up by water molecules? Or is it entirely something else? this might be a dumb question and no I haven't wiki'd it yet.
  2. Standard member wolfgang59
    Infidel
    26 Jan '10 08:34
    Originally posted by ysterbaard
    When the weather report say: " the humidity is 70% today, but tomorrow it should be 50%" Does it mean the 50% of the air is made up by water molecules? Or is it entirely something else? this might be a dumb question and no I haven't wiki'd it yet.
    by that reasoning 100% humidity would be water!!
  3. Subscriber ysterbaard
    AAPS forever
    26 Jan '10 08:52
    Yes. That's why I want to know what is the meaning of the term "50% humidity" and how is it calculated. And what happens at 100%. Obviously it cannot be that at 100% humidity air turns into water. Except if you go by wheight. Where a drop of water weighs as much as a whole lot of air. So if at 100% humidity a raindrop falls out of the sky. Still I would like a proper answer.
  4. 26 Jan '10 11:04
    http://en.wikipedia.org/wiki/Humidity#Relative_humidity

    I think that means it's the percentage of the maximum level of humidity that the air could sustain at that temperature.
  5. 26 Jan '10 12:18
    Originally posted by mtthw
    http://en.wikipedia.org/wiki/Humidity#Relative_humidity

    I think that means it's the percentage of the maximum level of humidity that the air could sustain at that temperature.
    Yes. At 100% humidity, it starts to rain. The actual amount of water air can hold is temperature and pressure dependent; that's why sunny weather tends to coincide with high pressure.
  6. Standard member sonhouse
    Fast and Curious
    26 Jan '10 23:07
    Originally posted by KazetNagorra
    Yes. At 100% humidity, it starts to rain. The actual amount of water air can hold is temperature and pressure dependent; that's why sunny weather tends to coincide with high pressure.
    So the part of rain that actually contains the water would be a lot more than 100% humid wouldn't it?
  7. Standard member ua41
    Sharp Edge
    27 Jan '10 03:13
    Originally posted by sonhouse
    So the part of rain that actually contains the water would be a lot more than 100% humid wouldn't it?
    I think it's improper to say water is humid
  8. Standard member sonhouse
    Fast and Curious
    27 Jan '10 05:33
    Originally posted by ua41
    I think it's improper to say water is humid
    On the other hand, it's certainly not dry
  9. 27 Jan '10 07:30
    Originally posted by sonhouse
    So the part of rain that actually contains the water would be a lot more than 100% humid wouldn't it?
    Your're just pulling my leg, but of course "humidity" references specifically a water vapour in air, not a dispersion of actual water droplets in air.