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Does stirring water help bring it to boil faster?

  1. Aug 8, 2012 #1
    Is it faster to leave the pot alone until it boils or to stir it every few minutes to increase convection?

    This is for a very large pot of over 50 litres using a 50 000 BTU commercial gaz burner at full power.
     
  2. jcsd
  3. Aug 8, 2012 #2

    sophiecentaur

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    You would expect faster heat transfer from flame to water when the temperature difference is high. So stirring the water (forced convection) will keep water with lower temperature in contact with the walls of the pan and should ensure more heat goes into the water and less is wasted into the surrounding air.
     
  4. Aug 8, 2012 #3

    cjl

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    My guess is that natural convection will mix it reasonably well in the first place, so there won't be much of a difference. You could always try it as an experiment (all you need is a stopwatch), and let us know the results...
     
  5. Aug 9, 2012 #4
    And weren't Joule's experiments done by stirring a fluid? Ideally the heat generated by stirring the pot would be added to the heat from the element, I know it would be very small, but that would also shorten the time to boiling.
     
  6. Aug 9, 2012 #5
    The stirring element might take some of the heat from the water. Waves caused by the stirring might also increase heat loss...and ultimately, you probably have to take the cover off to stir it.

    I say just let it be.
     
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