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Homework Help: Would the water remain in lquid form?

  1. Jul 16, 2013 #1
    Lets say Earths atmospheric pressure was reduced to 0.10 bar which is 10% Earths atmospheric pressure. The boiling point at this pressure is 113 degrees F. Due to the atmosphere being thinner there is a greater temperature difference with higher highs and lower lows in a 24 hour period.
    Lets say in a large area over the pacific ocean the air temperature in the day time reaches 130 degrees F and the temperature in the night time reaches 60 degrees F. This temperature difference is over a 24 hour period over a body of water. Would the oceans reach boiling point given the atmosphere is reaching above the boiling point for the given atmospheric pressure or will it remain a constant liquid because of the lower temperature?
    Last edited: Jul 16, 2013
  2. jcsd
  3. Jul 16, 2013 #2
    You can't get such a large temperature difference above the ocean. At daytime the sun will shine into the water, and it will have to heat a layer some tens of meters thick. Evaporation will limit the temperature rise also. Even with the sun directly overhead and all energy going into evaporation., you can only evaporate 1.6 mm/hour. ( 1kw/m^2 sunshine and 2.26 MJ/kg to evaporate water)

    rapid cooling at night over a warm ocean will surely produce clouds or fog.
  4. Jul 16, 2013 #3
    Even with an atmosphere 10% as thick as Earths the temperature difference wont be as big? I always thought that there would be bigger highs and lows with a thinner atmosphere.
  5. Jul 16, 2013 #4
    But to get the air above the ocean to heat up, you've got to heat up the ocean first, and the heat capacity of the ocean hasn't changed.
  6. Jul 16, 2013 #5
    Would a change in atmospheric pressure change the latent heat of vaporization of the water?
  7. Jul 17, 2013 #6
    So basically the ocean would remain liquid even with an atmosphere this thin? Interesting and i also forgot that there is alot of water to heat up.
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