How much of a difference does it make whether you blow on your soup to cool it down while in your dining room versus if you open the outside door in the winter and blow on it that way?
This would help settle the argument I'm having with my wife every time she does this. I'm not good enough at physics/math to calculate the answer myself.
- You have 300 ml of hot soup, heated to 90 degrees celsius
- the air temperature in your dining room is 25 degrees celsius
- the outside temperature is 5 degrees celsius
- your body temperature is 36.5 degrees celsius
- the temperature of your exhaled breath, while you are in the dining room, is about 35°C and 95% humid
- I'm guessing that when you open the window you are breathing in the air that is half influenced by the room temperature, and half by the outside cold (let's say 15 degrees celsius)
- the temperature of your exhaled breath, while you are blowing out of an open window, is unknown to me, but can be calculated
- you open the window and blow on your soup for 40 seconds
How much sense does your action make? :)