Now that I think about it, hotness can be a problem. We are constantly being hit by sun radiations that store a lot of energy. A rock can warm up until it melts down, but living organisms may have some problems with that kind of melting. Maybe it is because I don’t get along very well with hot stuff, from food to seasons, but we need a mechanism to cool down.
When you have, say a hot soup, it can be really hard to cool it down. Infact the only thing you can do – if you don’t want to put it in the fridge or to put inside the soup some ice cubes – is to blow on it. Or maybe you can put the soup out of the window, then the wind will blow for you.
Why blowing on something cool it down? I never thought about that, but it seems that many people think blowing on a cup of coffee cools it down because your breath is colder than the coffee and so blowing will eventually cool the coffee down. But, even if that can help, this is not actually the real reason. Coffee like the soup or pretty much every other food have a lot of water inside them or on the surface. The temperature of the object itself is enough to evaporate part of this water, and that’s why you see the little smoky lines going up from your coffee. Blowing on the cup, because your breath is probably drier than the coffee, helps the water to evaporate. Why this helps the coffee to get colder? Because evaporation, from the point of view of physics is an endothermic process, it is to say that it requires heat to occur. If you promote evaporation through other ways, like blowing on it, the evaporation process will steal the heat from the coffee and cool it down. You don’t believe me? Have you ever tried to blow on a coffee really close to the cup while wearing glasses? I can assure you they will be all foggy due to condensation of the water evaporated from the coffee!
Ok, this is interesting but how do we cool down? Try to think. How can a living organism get colder? If you have to invent a living organism who need to cool down, how do you do?
Many method we adopt to cool stuff require in contrast a section that actually warms up. Like the modern fridge. And to build up a process that take away heat is quite energy demanding because it’s normally not promoted by thermodinamic laws. So if our body wanted to invest on this way it should spend a great amount of energy in building this machinery. But evolution has promoted instead a smarter, more elegant and cheaper process.
What happens when a body warms up? It looses water. Well, why not using this collateral effect to our advantage? That’s what we really do. That’s absolutely genious! We simply take some water, which probably will be lost anyway, and put it on our skin sweating and let it evaporate! Amazing! The water evaporating through the sun heat or thanks to the wind will steal heat from our surface leaving it a little colder. That’s why when we get out from a pool and get dry simply standing without a towel, we get freaking cold!
Try to think the simplicity of this process, its smartness and cheapness. Sweating can be gross but it’s amazingly efficient! Simply exploiting the source of heat (the sun) we can cool down! The sun should warms us up but we, sweating, cool down! Some animals don’t sweat but loose heat through their mouth. Dogs for example stay with their tongue always out to loose heat.
Now that summer is getting closer we’ll sweat a lot. When you’ll sweat think about how amazing your body is; and meanwhile let me tell you a story.