Why is it that when you breath out, with your mouth wide open, the air is hot. But when you blow out with your lips making a whistle shape, the air is cooler?
I try to control my breathing so that I am making the same exact breath for each way. Same depth and same intensity of exhale. It always turns out as different temps.
I have some theories:
The wide-open-mouth breath has moisture coming straight out while the semi-closed-mouth causes the mouth lining to soak up moisture (and the heat in the moisture) or,
the wide-open-mouth breath does not linger in the mouth long enough to cool down.
These are some cute little theories, but I would love to know the actual technical reason!