On a hot hot summer day I like to go to local supper market to buy a tub of my favourite ice cream that bring home in shopping bag. It is hot hot outside the bag, and it is frozen cold ice cream inside the bag.
Now, according to the first law of thermodynamics, heat always flows from a reservoir (an object at high temperature) to a sink (a object at low temperature) when both are placed in contact with each other. The mode of heat transfer this way is called conduction of heat energy.
The question is - if heat flows from hot outside the bag – the big giant reservoir at about 35 degrees – to the cold ice cream inside the bag - a sink for heat below zero degree. Then why the bag, in the path of the heat flow, should get cold?
2006-08-07
03:01:42
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12 answers
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asked by
Shahid
7
in
Physics