Why does a lot of water vapour come suddenly after the heat source of boiling water is removed?












62














I have noticed this several times. When I am boiling water, a few seconds before its boiling point, vapours are formed as usual. But if I turn the gas off before boiling, the moment it turns off, I see a lot of vapours being formed all of a sudden from the hot water for a second or two. Can anyone tell me why this happens?










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  • 14




    Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
    – alex_d
    Dec 21 at 12:42


















62














I have noticed this several times. When I am boiling water, a few seconds before its boiling point, vapours are formed as usual. But if I turn the gas off before boiling, the moment it turns off, I see a lot of vapours being formed all of a sudden from the hot water for a second or two. Can anyone tell me why this happens?










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  • 14




    Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
    – alex_d
    Dec 21 at 12:42
















62












62








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8





I have noticed this several times. When I am boiling water, a few seconds before its boiling point, vapours are formed as usual. But if I turn the gas off before boiling, the moment it turns off, I see a lot of vapours being formed all of a sudden from the hot water for a second or two. Can anyone tell me why this happens?










share|cite|improve this question









New contributor




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I have noticed this several times. When I am boiling water, a few seconds before its boiling point, vapours are formed as usual. But if I turn the gas off before boiling, the moment it turns off, I see a lot of vapours being formed all of a sudden from the hot water for a second or two. Can anyone tell me why this happens?







thermodynamics everyday-life water heat-conduction






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edited Dec 23 at 0:18









psitae

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asked Dec 21 at 7:34









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  • 14




    Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
    – alex_d
    Dec 21 at 12:42
















  • 14




    Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
    – alex_d
    Dec 21 at 12:42










14




14




Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
– alex_d
Dec 21 at 12:42






Possible duplicate of Why is there more steam after a pot of water *stops* boiling?, although the answers here are better.
– alex_d
Dec 21 at 12:42












3 Answers
3






active

oldest

votes


















148














What you are seeing is not actually vapor - vapor is invisible. The mist seen above boiling water, commonly but inaccurately called vapor, is actually made of tiny droplets of liquid water, formed when the vapor cools down and condenses.



While the stove is on, the constant influx of vapor from the boiling water keeps the air above it hot, so condensation is minimal and there is little visible mist. When the gas is turned off, boiling stops, the air above the water cools down, and the vapor it contains suddenly condenses, creating a large plume of mist.






share|cite|improve this answer



















  • 11




    Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
    – user1717828
    Dec 21 at 16:22






  • 5




    ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
    – elliot svensson
    Dec 21 at 20:53






  • 1




    That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
    – user217702
    Dec 22 at 6:09










  • @user217702 If you consider this to be the right answer you should mark it as such.
    – Aaron Stevens
    2 days ago



















28














Without seeing your experiment we can only speculate, but my guess is that this is due to the convection currents generated by the combustion of the gas.



When the gas is burning there is a large volume of hot carbon dioxide and water vapour generated by the combustion, and this flows upwards and around the pan. This has two effects. Firstly it keeps the temperatures high around and above the pan, so it hinders condensation of the water vapour. Secondly the flow rapidly carries away and condensed water droplets that do form. As soon as you turn off the gas these two effects cease so there is more rapid formation of condensed water droplets.



You might be interested in reading Amount of Steam Generated using Gas burner and Induction cooker as I think this is related to your question.






share|cite|improve this answer



















  • 1




    I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
    – W W
    Dec 22 at 14:31





















7














Hotter steam has a diffraction index closer to air than steam which is cooler. As the steam cools the droplets get larger, increasing the diffraction making it appear like there is more, when in fact there is less.



Put another way, hot steam scatters light less than cool steam.






share|cite|improve this answer








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    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    148














    What you are seeing is not actually vapor - vapor is invisible. The mist seen above boiling water, commonly but inaccurately called vapor, is actually made of tiny droplets of liquid water, formed when the vapor cools down and condenses.



    While the stove is on, the constant influx of vapor from the boiling water keeps the air above it hot, so condensation is minimal and there is little visible mist. When the gas is turned off, boiling stops, the air above the water cools down, and the vapor it contains suddenly condenses, creating a large plume of mist.






    share|cite|improve this answer



















    • 11




      Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
      – user1717828
      Dec 21 at 16:22






    • 5




      ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
      – elliot svensson
      Dec 21 at 20:53






    • 1




      That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
      – user217702
      Dec 22 at 6:09










    • @user217702 If you consider this to be the right answer you should mark it as such.
      – Aaron Stevens
      2 days ago
















    148














    What you are seeing is not actually vapor - vapor is invisible. The mist seen above boiling water, commonly but inaccurately called vapor, is actually made of tiny droplets of liquid water, formed when the vapor cools down and condenses.



    While the stove is on, the constant influx of vapor from the boiling water keeps the air above it hot, so condensation is minimal and there is little visible mist. When the gas is turned off, boiling stops, the air above the water cools down, and the vapor it contains suddenly condenses, creating a large plume of mist.






    share|cite|improve this answer



















    • 11




      Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
      – user1717828
      Dec 21 at 16:22






    • 5




      ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
      – elliot svensson
      Dec 21 at 20:53






    • 1




      That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
      – user217702
      Dec 22 at 6:09










    • @user217702 If you consider this to be the right answer you should mark it as such.
      – Aaron Stevens
      2 days ago














    148












    148








    148






    What you are seeing is not actually vapor - vapor is invisible. The mist seen above boiling water, commonly but inaccurately called vapor, is actually made of tiny droplets of liquid water, formed when the vapor cools down and condenses.



    While the stove is on, the constant influx of vapor from the boiling water keeps the air above it hot, so condensation is minimal and there is little visible mist. When the gas is turned off, boiling stops, the air above the water cools down, and the vapor it contains suddenly condenses, creating a large plume of mist.






    share|cite|improve this answer














    What you are seeing is not actually vapor - vapor is invisible. The mist seen above boiling water, commonly but inaccurately called vapor, is actually made of tiny droplets of liquid water, formed when the vapor cools down and condenses.



    While the stove is on, the constant influx of vapor from the boiling water keeps the air above it hot, so condensation is minimal and there is little visible mist. When the gas is turned off, boiling stops, the air above the water cools down, and the vapor it contains suddenly condenses, creating a large plume of mist.







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Dec 21 at 10:59

























    answered Dec 21 at 9:53









    Aetol

    1,161116




    1,161116








    • 11




      Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
      – user1717828
      Dec 21 at 16:22






    • 5




      ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
      – elliot svensson
      Dec 21 at 20:53






    • 1




      That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
      – user217702
      Dec 22 at 6:09










    • @user217702 If you consider this to be the right answer you should mark it as such.
      – Aaron Stevens
      2 days ago














    • 11




      Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
      – user1717828
      Dec 21 at 16:22






    • 5




      ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
      – elliot svensson
      Dec 21 at 20:53






    • 1




      That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
      – user217702
      Dec 22 at 6:09










    • @user217702 If you consider this to be the right answer you should mark it as such.
      – Aaron Stevens
      2 days ago








    11




    11




    Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
    – user1717828
    Dec 21 at 16:22




    Great answer. I didn't even know what OP was talking about until you explained it. Kudos!
    – user1717828
    Dec 21 at 16:22




    5




    5




    ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
    – elliot svensson
    Dec 21 at 20:53




    ...and the hot combustion gases from the burner are also hiding the water vapor until the stove is off.
    – elliot svensson
    Dec 21 at 20:53




    1




    1




    That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
    – user217702
    Dec 22 at 6:09




    That's a great explanation. This also cleared my misconceptions about vapour. Thanks!
    – user217702
    Dec 22 at 6:09












    @user217702 If you consider this to be the right answer you should mark it as such.
    – Aaron Stevens
    2 days ago




    @user217702 If you consider this to be the right answer you should mark it as such.
    – Aaron Stevens
    2 days ago











    28














    Without seeing your experiment we can only speculate, but my guess is that this is due to the convection currents generated by the combustion of the gas.



    When the gas is burning there is a large volume of hot carbon dioxide and water vapour generated by the combustion, and this flows upwards and around the pan. This has two effects. Firstly it keeps the temperatures high around and above the pan, so it hinders condensation of the water vapour. Secondly the flow rapidly carries away and condensed water droplets that do form. As soon as you turn off the gas these two effects cease so there is more rapid formation of condensed water droplets.



    You might be interested in reading Amount of Steam Generated using Gas burner and Induction cooker as I think this is related to your question.






    share|cite|improve this answer



















    • 1




      I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
      – W W
      Dec 22 at 14:31


















    28














    Without seeing your experiment we can only speculate, but my guess is that this is due to the convection currents generated by the combustion of the gas.



    When the gas is burning there is a large volume of hot carbon dioxide and water vapour generated by the combustion, and this flows upwards and around the pan. This has two effects. Firstly it keeps the temperatures high around and above the pan, so it hinders condensation of the water vapour. Secondly the flow rapidly carries away and condensed water droplets that do form. As soon as you turn off the gas these two effects cease so there is more rapid formation of condensed water droplets.



    You might be interested in reading Amount of Steam Generated using Gas burner and Induction cooker as I think this is related to your question.






    share|cite|improve this answer



















    • 1




      I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
      – W W
      Dec 22 at 14:31
















    28












    28








    28






    Without seeing your experiment we can only speculate, but my guess is that this is due to the convection currents generated by the combustion of the gas.



    When the gas is burning there is a large volume of hot carbon dioxide and water vapour generated by the combustion, and this flows upwards and around the pan. This has two effects. Firstly it keeps the temperatures high around and above the pan, so it hinders condensation of the water vapour. Secondly the flow rapidly carries away and condensed water droplets that do form. As soon as you turn off the gas these two effects cease so there is more rapid formation of condensed water droplets.



    You might be interested in reading Amount of Steam Generated using Gas burner and Induction cooker as I think this is related to your question.






    share|cite|improve this answer














    Without seeing your experiment we can only speculate, but my guess is that this is due to the convection currents generated by the combustion of the gas.



    When the gas is burning there is a large volume of hot carbon dioxide and water vapour generated by the combustion, and this flows upwards and around the pan. This has two effects. Firstly it keeps the temperatures high around and above the pan, so it hinders condensation of the water vapour. Secondly the flow rapidly carries away and condensed water droplets that do form. As soon as you turn off the gas these two effects cease so there is more rapid formation of condensed water droplets.



    You might be interested in reading Amount of Steam Generated using Gas burner and Induction cooker as I think this is related to your question.







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Dec 21 at 8:51

























    answered Dec 21 at 8:24









    John Rennie

    270k42532781




    270k42532781








    • 1




      I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
      – W W
      Dec 22 at 14:31
















    • 1




      I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
      – W W
      Dec 22 at 14:31










    1




    1




    I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
    – W W
    Dec 22 at 14:31






    I've also observed the described phenomenon on my stove which is electric and thus doesn't have an combusting gasses. This seems to imply that there is at least something else at play.
    – W W
    Dec 22 at 14:31













    7














    Hotter steam has a diffraction index closer to air than steam which is cooler. As the steam cools the droplets get larger, increasing the diffraction making it appear like there is more, when in fact there is less.



    Put another way, hot steam scatters light less than cool steam.






    share|cite|improve this answer








    New contributor




    Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.























      7














      Hotter steam has a diffraction index closer to air than steam which is cooler. As the steam cools the droplets get larger, increasing the diffraction making it appear like there is more, when in fact there is less.



      Put another way, hot steam scatters light less than cool steam.






      share|cite|improve this answer








      New contributor




      Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.





















        7












        7








        7






        Hotter steam has a diffraction index closer to air than steam which is cooler. As the steam cools the droplets get larger, increasing the diffraction making it appear like there is more, when in fact there is less.



        Put another way, hot steam scatters light less than cool steam.






        share|cite|improve this answer








        New contributor




        Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        Hotter steam has a diffraction index closer to air than steam which is cooler. As the steam cools the droplets get larger, increasing the diffraction making it appear like there is more, when in fact there is less.



        Put another way, hot steam scatters light less than cool steam.







        share|cite|improve this answer








        New contributor




        Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        share|cite|improve this answer



        share|cite|improve this answer






        New contributor




        Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        answered Dec 21 at 17:13









        Anthony Bachler

        711




        711




        New contributor




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        New contributor





        Anthony Bachler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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