Why Sweating Cools You Down

Thinking about sweat on a molecular level

[krytek]

Wow I've never seen that good of an explanation with so much depth.
Sal's getting better all the time. Favorited.

[BibleBeltPearlist]

This also explains why water boils at a certain temperature because you can't add any more energy to the water because it is cooled by the water molecules that are evaporating. More energy more evaporation, no raising of temperature of the water.

[bukaifrancisco]

Khanacademy is one of the best educational videos. Thanks a lot!!! Please keep posting.

[uberasra]

which is why you don't wear shorts because its hot, you're just making yourself hotter.

[matt]

That's basically what I said, but a little simpler than what I said. But that's why I wouldn't be a good teacher. I tend to explain things in the less-than-simplest way of viewing it.

[speaktone]

Evapouration results in cooling, cooling is a result of evapouration, heat from the body and air movement. Thats always been my logic, thanks for the extension into the science. Where you say about heat, its all relative to the point from which you measure, there is not hot or cold in such definate terms, more a variation of level of heat, we try to oppose to understand like left hand and right hand but in reality they're more the same than different yet still opposite as functions of the centre

[matt]

Yes but only the highest kinetic energy evaporates because getting rid of it has the greatest effect. If you are familiar with economics then you could apply the the concept of Marginal Benefit/Profit and Diminishing Returns to this situation.

[teaandcrochet]

I totally understand now :) Thanks for taking the time to make these!

[MunkiZee]

As you may know, salt changes the freezing and boiling temperature of water. In molecular terms, it affects how much energy each individual molecule needs to break bonds and change state. In this example the state change is evaporation (boiling), going from liquid sweat to vapour. I'd like to see a video on how homeostatic process is affected by the temperature gradient

[bobsagget]

That's a fair explanation but you can simply think of it as cells being made up of many molecules (water being one of them of course) which means cells are of course much bigger. (much, much larger than a single H2O)

[FireOwlBeleiver]

Hmm I was strangely thinking of how this precisely worked yesterday evening after running. Thanks!

[MaxwellSDSU]

When your body gets hot, you sweat.
When the water portion of sweat evaporates, it takes some of your heat with it.
Multiply this process across thousands of sweat particles evaporating, and eventually your body begins to cool off.

Hopefully that's an understandable, less technical definition of the concept.

[sapoirier]

Yes, he said that, but it's not that simple. The act of evaporating is endothermic so the energy that each molecule takes with it is not equal to the energy that it had a moment before it left. It doesn't just leave, leaving a lower average. It actually steals energy from its surroundings (i.e. you) cooling you down. You can try it yourself by taking room temperature rubbing alcohol and putting it on your arm, it's volatile so it will evaporate quickly and cool you down.

[MunkiZee]

So to give a straight answer to your question (lol) the salt in your sweat actually makes for less effective heat distrubtion. If you compare pools of sweat on skin to puddles of water on the pavement you'll have an idea of the kind of evaporation rates involved, and puddles get more breeze. I'd say the main benefit of the salt being there in sweat is that it's no longer inside the body

[Basram]

@SabaskaTheNoob water can evaporate without having reached boiling point. the boiling point of water just states where the general heat capacity is so high to cause the water to boil. compare your statement to a pot of water suddenly evaporating when reaching 100 degrees

[nailo]

this is the type of explanations i love to learn. is there a way to find lectures that take this method of explanation

[sapoirier]

But you didn't mention that when it evaporates, the act of the phase change steals energy from its surroundings to cool you down. It's is the phase change that cools you, not as simple as you explained.

[alxjones]

Not everything can be explained in molecules, some things require a deeper look into the world of atoms, or even the particles withing them, namely protons, neutrons, and electrons. Also, no one knows how gravity works on the quantum level, so you're not alone.

[Dribbles]

Interesting, I'll look it up as I'm not sure what exactly it carries but I know your correct.

[foresthanke]

Not every molecule reaches 100 degrees, if they did your sweat would all evaporate instantly, it's just a molecule here and there that reach the temp they need to and break free