Why does steam cause burns? [ENDORSED]

[paulina_higashi_1G]

Can someone explain the reasoning again for why stream causes severe burns?

[Shannon Shams Disc 3I]

Steam causes more severe burns than boiling water because when steam hits someone's skin, it will condensate and turn back into water. This is an extremely exothermic process, and will release a lot of heat/energy, which causes the more severe burn despite steam and boiling water being the same temperature

[Henley Roy- 1D]

Hi,
Steam is a gaseous substance. When it comes into contact with the skin it cools (releasing heat), and it also undergoes a phase change, condensing to a liquid. Since the physical change from a gas to a liquid is an exothermic process, it releases additional energy in the form of heat when changing states. This causes steam burns to be more severe than liquid water burns, as the steam is not only cooling to release heat, but also changing states to release heat, causing a higher overall net release of heat than water.

[adam_simshauser_1l]

Another way to rationalize it is by accounting for the energy of a phase change. There is technically more energy, and therefore heat when dealing with gas than hot water.

[Richard Chiu 1I]

Steam cause burns because it undergoes rapid phase change when it comes in contact with your skin. This is because your skin will cool the steam from a gaseous form into a liquid form, which releases a large amount of energy. A great way to view this is to see a phase change chart for water and compare the energy required for a hot liquid to cool versus a hot gas to cool.

[Christopher Lai 2I]

As others have stated, when steam condenses to water large amounts of heat are transferred from the gas to your skin during the phase change (latent heat of condensation). I also wanted to add that steam causes more severe burns than boiling water because it has additional energy from the latent heat of vaporization. It can be counterintuitive that steam can cause more severe burns than boiling water but understanding the phase changes helps to show why!

[Jessica_Lin_1J]

If you also look back on Professor Lavelle's 1/23/23 lecture on BruinLearn>UCLA Media Reserves, there is a very helpful diagram depicting the energy supplied for water's phase changes. If we specifically compare the heat supplied for the region indicating "Solid Melting" and "Vaporizing," we see that 40.7 kJ.mol-1 is required to transition form liquid to vapor. However, transitioning from solid to liquid only requires 6.01 kJ.mol-1. Essentially, vapor cooling down releases more energy at 100C than liquid does at 100C, causing more energy to be taken up, for example, by the skin.

[Sophie Vansomphone 1J]

Steam causes more severe burns because it contains the heat of boiling water and the heat of condensation making it contain more heat than water even at the same temperature.

[James Pham 1A]

Steam causes burns due to the high amount of enthalpy released as it cools down, condensates, and cools down to body temperature once it hits the body.

[Karissa_Lee_1A]

Steam causes more severe burns because the amount of work to turn water to vapor is greater than the work to boil water.

[Keanu Ngo 3B]

There is more energy released when steam goes under a phase change than hot water. Therefore, it releases more energy on the skin.

[Eli Weiss-Hung 2C]

Steam and water at 100 degrees Celsius are the same temperature, but steam carries a lot more energy. When steam hits someone's skin it cools significantly, causing the steam to condense back into water. This is a very exothermic reaction, as water is much lower in energy than steam, so a lot of energy is given off as heat. This heat given off during condensation is what causes the severe burns.

[Gabriela Alfaro]

Since the steam is at higher temperature than your skin, once in contact, the temperature of the steam will decrease via an exothermic process as the heat goes to your skin and the gas becomes liquid.

[Nishanth Vemuri 2L]

When steam condenses once in contact with skin, or when the gas turns into water, the reaction is very exothermic, meaning it releases a lot of heat. This is because the amount of energy put into a system of making a solid turn into a gas is very high, so when reversed, the same amount of energy is released. This energy is heat, and is given off right on the skin.

[405750027]

When steam is contacted with your skin it is much higher temperature but will decrease through an exothermic process doing so the heat from the steam will go through a phase change where the gas will turn to a liquid.

[parisnortega1]

The steam penetrates through the skin pores onto the lower skin layer, the dermis. Only there does the steam condense, thereby releasing its thermal energy directly onto the sensitive dermis -- and thus directly triggers second-degree burns

[Graciela Ayala 2I]

I think one of the most helpful things for this to stick with me was to look back at the diagram Dr. Lavelle used in his lecture the day that question came up, along with the values that went along with it so you can see both the physical and numerical reasoning for how big of a jump it is in overall enthalpy.

[Audric Banuelos 1A]

Steam causes more severe burns than just boiling water because when steam hits the skin, it turns back into liquid while also releasing extra energy, making it an exothermic reaction. Since it turns back into boiling water while also releasing extra heat, it will cause the burn to be even worse.