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when steam hits your skin, a lot of energy will be released as it condenses into a liquid, undergoing a phase change (because your skin temperature is a lot cooler in temperature), this energy release causes a much worse burn than if the same amount of boiling water were to hit your skin where it would decrease in temperature (to your skins temperature) but would not have to go through a phase change.
In order for to convert water into steam, it has to absorb a lot of energy to change phases. From my understanding, when steam gets into contact with your hand, which is relatively cooler, it starts to condense. This means that all that energy that was required to change the liquid into a vapor in the first place is reversed, and is released onto your hand.
So the burn was worse due to more energy being exerted on the skin? But, how does that energy manifest if it does not cause an increase in temperature? In other words, what happens to that excess energy? What is it doing if it isn't heating the steam?
I don't know if I can explain this that well but think of it in terms of that graph Lavelle had on his presentation. It takes about 41 kJ for vapor to become a liquid at 100 degrees Celsius, but it's still at 100 degrees so it has to use even more energy to go to a lower temperature. Meanwhile, it doesn't take nearly as much energy for the liquid to cool from 100 degrees. Basically, the energy is being used to reform the bonds between the molecules to go into the liquid state, which takes longer than when liquid at 100 degrees is already in the liquid state (I think).
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