Here is some “basic physics” for you. Hot air rises. Heat doesn’t rise. It radiates in all directions.
“Here is some “basic physics” for you. Hot air rises. Heat doesn’t rise. It radiates in all directions.”
Yes, heat from a specific source does radiate in all directions. It also moves from a warmer area to a cooler area.
The earth radiates heat out into space, where it is eventually dissipated by cool air. That heat is, indeed, “hot air.” (It’s one of the reasons it is colder on top of a mountain than it is on the desert below.)
And, as you know, heat is transferred via radiation (transfer of heat from a warm object to a cooler object); conduction (transfer of heat between connected or touching objects); and convection (transfer of heat by circulation of liquid or gas).
So, the thread is about heat in homes; specifically, how Southerners dealt with their natural environment (especially before man-made electricity).
The sun beats down on the roof of the house, and the heat from the sun radiates onto the roof (warmer to cooler transfer); that heat conducts through the roof and radiates to the attic floor and conducts again from the attic floor to the ceiling below; that heat radiates to cooler surfaces in the house, where it moves via convection (the medium being a gas; i.e., air).
Thus, that heat necessarily means hot air. And hot air is just air that has been heated.
And since heated air is less dense than colder air, it necessarily must rise.
Whew!