Question

If there are two identical pots of water next to one another and you bring both of them to boiling but remove one from the heating device but keep one of them on the device but reduce the temperature to 60 degrees C which pot of water will reach 60 C first? Thank you for your help!

Answer 1

Let's say Pot 1 is the one which has been brought to boiling and then removed.

Let's say Pot 2 is the one which has been brought to boiling and then temperature is set to 60 degrees C.

So, initially temperatures in both the pots are 100 degrees C.

One important thing to understand is that water in any of the two pots starts cooling by radiating heat out and by interacting with the surrounding materials(conduction) and air(by convection).

And when the temperature of heating device is set as 60 degrees, it means that the temperature of heating tubes of device is 60degrees. So within a few minutes, temperature of heating tubes of Pot 2 is 60 degrees and of Pot 1 is greater than room temperature but quite less than 60 degrees and keeps decreasing .

And we know that the dissipation of heat depends on temperature difference between water and the surrounding medium. In Pot 1, temperature difference between water and heating tubes is quite more than that of water and heating tubes in Pot 2. Dissipation of heat to air is same in both Pots because temperature of air is same every where.

Therefore, in Pot 1 heat dissipation through heating tubes is more than that of in Pot 2. So, Pot 1 cools more quickly to 60 degrees.