Ask A Scientist Physics Archive

name         Helen P.
status       student
age          14

Question -   Please can you tell me whether convection only 
travels in currents (caused by changes in density)?  If so how are 
draughts (through windows and doors) caused by convection?
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Convection is the transfer of heat from an object to a
fluid, or vise versa.  The fluid could be air, water,
etc.  The fluid has to be moving though.

The difference between convection and conduction is
like if you have a hot brick, and you either let it
cool in your hands (conduction), or you toss it away
(convection).

Hope I did not confuse you more.

-Wil Lam
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