Science Buddies: "Ask an Expert"

if we keep one room(A) in extream hot condition n another room(B) with cool temperature n another room(C) between the two joining the two rooms(A) and (B) .... then will a current of air produce between them in that middle room(C) ? ... n if yes then nearly how much? n what are the conditions to produce it?

Hi Sohankumarbehera - Wind or breeze is notmally created by pressure differences, not just temperature differences. Although there woulf be some air movement between the rooms, it would be very slight and probably not measureable. This air movement would be similar to in a house with rooms at different temperatures. I hope this helps.

but creating a temperature difference will creat the pressure difference too .... n my aim is also the same thing only... i.e creating pressure difference through temperature difference ...

Hi Sohankumarbehera,

I agree with the above - the difference will be very small and difficult to measure.

I have asked another expert to have a look at your question, so maybe we will get another idea on how to test it.

Tonya

Sohankumarbehera, you said "but creating a temperature difference will creat the pressure difference too .... n my aim is also the same thing only... i.e creating pressure difference through temperature difference ..." You are half right. The pressure of a gas is proportional to its temperature times its density. In the case you are interested in, the difference in temperature between the two rooms is compensated by a difference in the density of the air in the two rooms. If the airway connecting the two rooms is large enough the difference in density will cause the cooler (and denser) air to flow very gently down and under the hotter (and less dense) air in the other room. This is the principal behind gravity-fed central heating as an example. On a much larger scale it is what goes on meteorologically in a warm front -- a large mass of warm air slides over a denser mass of cooler air.

Once the temperature in the two rooms has become stratified with the warm air above and the cold air below it becomes difficult to get rid of the (often unwanted) temperature gradient; in houses one must often resort to fans to get the air masses to mix.

For more on this topic, look up "ideal gas law" on Wikipedia.

I hope that clarifies things.