Can water evaporate at room temperature?

I poured water into a cup and drew a line at where I first initially poured it. It’s been 3 days and the water has gone down about 2-3cm below the line. I have not exposed the water in the cup to sunlight, nor has anyone or anything touched the cup. It is isolated by itself and the water is going down. Any theories as to why this may be? I thought water evaporated at 212°, not at room temperature. Thanks in advance!

12 Answers

  • Anonymous
    1 year ago


    0°C is the “triple point” of water, because it can exist as a frozen solid at 0°C, a liquid at 0°C and as a gas at 0°C.

  • 1 year ago

    Yes, water evaporates at any temperature. That is how clothes dry and puddles dry up after a rain. Water boils at 212 degrees.

    At any temperature, a few water molecules occasionally gain enough kinetic energy to escape into the air.

  • 1 year ago

    As long as the relative humidity of the air is less than 100%, water will evaporate.

    This includes ICE.

    Take a look at the ice cube tray in your freezer and you will see that, over time, the ice cubes become smaller due to evaporation.

    When water gets to the boiling point it changes state from a liquid to a gas (steam.)

  • Tom S
    Lv 7
    1 year ago

    Of course, unless the relative humidity is 100%

  • 1 year ago

    Good answers here. Water will evaporate at room temperature based on temperature, humidity and air circulation. But no one has mentioned surface area which will also be a factor.

  • 1 year ago

    The humidity in the room. And everyone’s room temperature varies. Specify what temperature.

    • Yes. Evaporation is where water molecules break off and float into the air. The hotter the water is the faster it evaporates as the molucules are jiggling about faster. Air movement dries much faster - even over ice - freeze drying. Low humidity too - More room in the air. Condensation the reverse.

  • 1 year ago

    Heck, even ice "evaporates" although the word is sublimate. volatile substances lose contents to the gas phase fairly quickly without ever achieving the boiling temperature. The rate of loss to the gas phase varies with temperature, of course.

    When you sweat, does the sweat evaporate? it sure doesn't ever boil.

  • 1 year ago

    Of course. Why do clothes dry when on a clothesline outside even when the temperature is LOWER than room temperature.

    Even ice evaporates slowly. ( sublimation ).

    Now the rate of evaporation is dependent upon the temperature and the humidity.

    Because I live in a dry climate if I put a wet dish on the table it tends to dry in a few minutes. On its own.

    Outside with a bit of breeze they publish the rate of evaporation each day. Typically 5mm or more each day in summer. But under 1mm per day in winter.

  • Vaman
    Lv 7
    1 year ago

    You draw a Maxwellian distribution, which looks like inverted V. The pointed place where the maximum of the water temperature resides. Y axis is the number of water molecules and x axis you can call it energy. For evaporation you need certain energy. Draw a vertical line at that point on the x axis. All water molecules beyond will evaporate. But there can not be vacuum. More molecule move into that region and they get evaporated. This is continuous. Ofcourse evaporation rate depend on the back ground temperature and humid. In the absence of these two, one explain with the picture given above. Even oil evaporates but slowly because of Maxwellian distribution of oil molecules.

  • Yes. If water didn't evaporate at room temperature, nothing would ever dry.

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