Water. Part 2/2 : How does sweating cool us down?

Water, again, is responsible for evaporative cooling. 

Water molecules are bonded to each other by hydrogen bonds. Lots and lots of hydrogen bonds are difficult to break. Water requires a high amount of energy to break these bonds. As a result, it is relatively difficult to evaporate water into a gas. If you want to get into the physics of it: this is known as a high latent heat of vaporisation. Although that can be annoying when it takes longer than a minute to bowl the kettle, water’s properties allow animals to maintain a regular body temperature. 

States of Matter. Photo Credit: Dreamstime

As our bodies begin to heat up, we want to cool down fast. We don’t want to get too hot because then the enzymes in our bodies begin to denature (stop working). When enzymes denature our bodies can’t complete reactions fast enough so we can’t digestive our food or build proteins to make us grow. Both are essential and are 2 of the 8 criteria for being classified as a living thing. 

Our own bodies know this and they respond in the form of thermoregulation, which includes perspiration (sweating). 

Sweat alone does not create a cooling effect. The evaporation of sweat leads to a cooling sensation. Therefore, the property of water itself is what makes sweating effective.

As we sweat, water is evaporating off of our skin and taking all of the heat energy with it; cooling the body down. Water takes the heat energy with it because water requires a high level of energy to evaporate (it takes in heat to turn into vapour).

Photo Credit: Jess Herr on Google Sites

This may seem like an obvious regulation system but it is something that I only learnt recently. As I said in my “Meet Jiya” post I am continuously learning as a student.

This made be think about how much water has to offer to every living thing on Earth and why we are so dependant on it to survive.

My next glass of water will be 100 times more refreshing.

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