Why does steam cause severe burns?

[Olivia D 3B]

At the end of lecture, Dr. Lavelle asked the question, "Why does steam cause severe burns?" I understand that the answer has to do with the heating curve for water, but I was wondering if someone could provide me with a more solid and conceptual answer to this question.

Thank you:)

[Anna Wilborn-1L]

When steam is at 100 C, it has an enthalpy of 40.7 KJ per mole while when liquid is at 100 C, it has enthalpy of 7.5 KJ per mole. The higher enthalpy gives vapor the ability to cause more severe burns because as the vapor touches the skin, it releases 40.7 KJ per mole of heat to become a liquid and then will release part of the 7.5 KJ per mole of heat until at the skin's temperature which is more than the part of the 7.5 KJ per mole of heat the liquid will release until at the skin's temperature.

[Devon Shao 1E]

Hi :)

Steam causes more severe burns than water at the same temperature (100 degrees celsius) because steam has a higher enthalpy, or higher total heat content. This is because in order for a liquid to vaporize into a gas, heat is added and temperature does not change. Thus, even if steam and hot liquid are both at 100 degrees celsius, steam has a much higher total heat content, which makes it much more harmful for skin.

I hope this made sense, its an explanation that is missing a bit of complexity in the exact numbers and reasoning, but hopefully the simplicity and coherency makes up for it.

[Rose Arcallana 2B]

Hello, so basically overall the transformation of heat as steam goes as follows: steam -> phase change from steam to liquid (40.7 kJ) -> liquid temp cooled to human temperature (~ 6 kJ). This results in a roughly 46 kJ/mole heat transfer onto the human skin, which is very high energy to be transferred. In comparison to an already liquid 100 C water that will not need to go through a phase change, only ~ 6 kJ heat transfer. Hope it helps!

[Michelle Li 2B]

Hi! Steam causes severe burns because it has to go through an additional phase change when it touches your skin, since it goes from gas to liquid. This phase change releases energy in addition to the energy released by cooling the liquid water down to your body's temperature. Therefore, this would be a greater release of heat onto your skin than for liquid water, which doesn't have to go through the phase change.

[RobinFong_2B]

At the end of lecture, Dr. Lavelle asked the question, "Why does steam cause severe burns?" I understand that the answer has to do with the heating curve for water, but I was wondering if someone could provide me with a more solid and conceptual answer to this question.

Thank you:)

Steam, the gaseous state of water, requires a lot of energy in order to change states from liquid to gas. That energy is given off as heat and can thus severely burn someone if they come into contact with steam.

[Omer_Abdelrahim_1B]

In order to move from a liquid to a gas state, water has to absorb much more energy to form it's gas form vs the liquid form. I also think that's why the steam engine worked, because of the pressure related to the amount of work and energy in the engine.