Boiling water with ice
diode.zone
This is a vapor pressure experiment, the jar was sealed while the water was boiling on a hot plate, so the steam displaced all the air out of the jar. After sealing, the jar was quickly removed from the heat and let cool. now, there is only water and water vapor in the jar (give or take, there is some hair and dust in the water, and probably some remaining dissolved gases). The pressure inside is always equal to the vapor pressure of the water, which depends on temperature. At room temperature, it's almost a vacuum inside, and as the temperature increases, so does the pressure. At 100C, the pressure inside is one atmosphere, which is the same condition under which the jar was sealed. Whenever there is a heat transfer from the bulk water to the lid (condensing the vapor), the water boils, no matter the absolute temperature. In this case, the water was luke warm, and I could hold the jar while it boiled inside. Another interesting property is how easily the water cavitates. simply moving the jar around or tapping lightly on the top causes the water to separate from the walls of the jar, and it makes a clapping sound.

This is a jar full of only water (liquid and vapor). It boils at any temperature when you apply something cold enough to the top, like ice.

cross-posted from: https://lemmy.sdf.org/post/2697716

I put water in a jar and sealed it while it was boiling, and now it boils at any temperature. Super fun demo to try.

  • blindsight@beehaw.org
    8·
    1 year ago

    I’ve read the video description several times, and I still don’t understand. This bit in particular:

    Whenever there is a heat transfer from the bulk water to the lid (condensing the vapor), the water boils, no matter the absolute temperature.

    Is the idea that water condenses at a lower energy state, so when cold is applied, the water vapor turns to liquid? If so, what does that have to do with the water boiling?

    I don’t understand.

  • FlintenUschi@feddit.de
    3·
    1 year ago

    Now I wonder if the pressure inside is low enough that you could reach the water’s triple point If you cool it down to 0,01°C

    • sixfold@lemmy.sdf.orgOPEnglish
      4·
      1 year ago

      Yes definitely. The pressure will drop along the vapor pressure curve all the way to the triple point, gently boiling all the way if you remove the heat from the vapor and not directly from the water.

      • FlintenUschi@feddit.de
        2·
        1 year ago

        Thank you for the answer. I’m tempted to try it, but I’m guessing this is not something you can easily do at home.

        • sixfold@lemmy.sdf.orgOPEnglish
          1·
          1 year ago

          Do it! it is easy to do at home! Just wear some gloves and safety glasses, those jars can easily shatter during the heating process if you use too hot of a heat source. I recommend a glass top electric stove, or put some kind of metal plate between your jar and the burner to help spread out the heat. Once you seal the jar, take it off the heat right away, so it doesn’t build pressure. I boiled mine for a few minutes before sealing to try and get some of the devolved gasses out, and lightly set the lid on top to help the steam push out all the air.

  • CanadaPlus@lemmy.sdf.org
    1·
    1 year ago

    Hmm. I wonder if you could make a higher-quality vacuum this way by adding a getter. You’d think it would still be safe-ish with reactive metals because bulk liquid water never needs to be anywhere near the chamber (air will remove heat too, just somewhat slower).