Q: How are we able to change...

Q: How are we able to change the temperature of our breath? We blow warm air to thaw out cold hands, but cool air to soothe a burn.

A: The temperature of your breath is the same in both cases. But if you have been outside in winter, your hands are colder than your breath, so it feels warm. A burned finger, in contrast, is warmer than your breath, so the air feels cool.