I’m thinking that no, it doesn’t. Which begs the question of why we do it? Is it a psychological thing?
Yes, it does. By blowing over it, you evaporate some of its water, which cools it down. See also https://en.wikipedia.org/wiki/Enthalpy_of_vaporization
Thank you.
I think I saw a show 20 or so years ago that tried to debunk this and obviously either they messed up, or I wasn’t paying attention.
(The show was called Brainiac).
Air cooled engines quite literally stay cool by being blown on.
You can test your hypothesis of “no, it doesn’t” pretty easily. Feel free to report back with results and method used.
Methods:
- Make a cup of Hot Chocolate
- Get two spoons, put them in your hot chocolate to warm up to remove the variable of heat transferring into the spoon.
- Take one spoon out, fill it up, blow on it for a few seconds, then put it in your mouth.
- Take the second one out, leave it out for the same amount of time you would have if you had blown on it, then put it in your mouth.
Report on temperature difference. If you had an instant-read thermometer you could even be more certain of the results.
It does. Heat conduction is faster when the temperature difference is large. Air soaks up a lot of heat, so still air is a poor heat conductor. If you’re blowing it around, you’re increasing the amount of fresh, colder air that can interact with the food.
One spoonful and a couple of breaths is small enough stuff to have a relatively small effect and a lot of error margin, though.
Convection says yes.
Yes, it does
It doesn’t beg the question, Mr Tyson. Stick to boxing.
Besides evaporation, blowing on something which is very hot will bring it closer to room (or breath) temperature by removing the air right next to it which has been heated up already and is ‘protecting’ the hot item a bit from direct exposure to the room air. When you blow that hot air away the hot item then touches the room air and heats that up, which cools it down.
The same applies to cold things, you can melt ice cream for example much faster by blowing on it even if you use a fan instead of hot breath.
It works well enough for CPUs and graphics cards.
