Steam

[Andrew Yoon 3L]

I'm still a bit confused on why steam causes more severe burns compared to water at 100°C. Is it because the energy that released when it touches someone's hand is still going to be the same temperature when it is a gas, compared to when it is a water, which would temperature would decrease as more energy is released?

[705340227]

The steam burns more than the water because more energy is released from the steam than the water. He went through the math in lecture but the energy released when steam touches your skin is much more than water. This is caused by the phase change from gas to liquid releasing energy as well as the heat.

[Amanda Chang 2B]

Steam causes more severe burns because steam holds more heat energy at 100 degrees Celsius than water at the same temperature since the phase change from liquid to vapor requires a large amount of energy.

[Mackenzie Van Val 3E]

The steam causes more severe burns because of the large amount of energy it takes to turn liquid water into steam. If you think about the steam as condensing when it hits your skin, then the steam must release all the energy it took to phase change into vapor, and therefore it releases a lot of heat energy onto your skin. In contrast, boiling water will decrease in temperature, but it does not have to release the energy of that phase change, so the burns are less severe.

[Chinyere Okeke 2J]

Steam burns are more severe than water burns because steam releases more energy when it makes contact with the skin. The steam changes from vapor into a liquid when it touches the skin, which releases a lot of heat (energy), and then it releases more energy in order to become the same temperature as the skin (it is in contact with).

This goes back to a concept in thermodynamics which is if two systems are in contact their temperatures will reach a final temp in between the initial temp of both systems. So when the steam makes contact with the skin it will transfer heat to the skin until they both reach a thermal equilibrium.

[Edwin Liang 1I]

Steam burns are more severe because the energy used to break the hydrogen bonds is an endothermic reaction. When it touches your skin, it becomes a liquid, which is an exothermic reaction, so all the energy used to break the hydrogen bonds are released in heat.

[Austin Aldujaili 2D]

Since steam is at a different phase of matter than liquid water, once it touches your skin, it will release all energy it holds until it becomes liquid water (this is an exothermic reaction). From the energy diagram he showed us in lecture, you can see how it takes a lot of energy given off for steam to have a phase change back into liquid water. This energy is released very quickly when steam touches your skin and that is what causes the severe burns.

[sophia kosturos 2B]

steam causes more severe burns than water because of the very large enthalpy of vaporization value. Since more heat is required in vapor formation than in liquid formation, a greater amount of heat is released upon coming into contact with a cooler surface (skin) because the phase changes from vapor to liquid instead of just releasing heat from a liquid form.

[James_Hankee_1C]

Steam causes severe burns because as water is heated from a liquid to a gas, the heat is being absorbed into the bonds and breaks bonds. The heat is stored within and when you touch the steam, all this stored energy gets transferred to your skin and causes a severe burn

[Ian_Lee_1E]

It basically goes like this.

when vapor meets our skin, which is around 36 degrees Celsius, the vapor, due to thermodynamic equilibrium, cools down to a liquid state with temperature of 36 degrees celsius.

In order for this to happen, the vapor first needs to condense to a liquid.

If we see the chart, in order to the vapor to completely transform into a liquid, it needs to release all the "liquid vaporizing" energy to our skin + the amount of energy that changed the temperature of water to 100 degrees from 36 degrees celsius.

That energy is far greater than just a liquid in 100 degrees celsius.

[Ayesha Aslam-Mir 3C]

I wanted to further this question; looking at the phase change diagram, we see that heat is continuously supplied during the "liquid vaporization" stage while the temperature remains the same, meaning that when the steam contacts the skin and begins to condense, not only is it at 100 degrees celsius, but it will release all that energy that it took to vaporize the liquid in the first place in order to move phases (from vapor to liquid). steam go brrrr heat release

[Earl Garrovillo 2L]

It's because steam is a gaseous state. If you remember the phase diagram Lavelle showed, there's a significant amount of energy needed to convert water into steam. When steam hits your skin, it condenses back to water and all that energy released from changing from a gas back into a liquid is released on your skin. So although they're the same temperature, that extra energy from the phase change of gas to liquid causes more severe damage than just the hot water at the same temperature.

[Valerie Doan 3I]

Basically, water has a higher enthalpy of vaporization (in this case condensation) due to hydrogen bonds. When these bonds re-form, they release heat, causing severe burns.

[AJForte-2C]

Steam burns more, because there is more energy in the steam compared to water at the same temperature. This is because water has a high enthalpy of vaporization.

[Abhinav Behl 3G]

The reason why steam causes more severe burns when it comes into contact with your hand than water is that there is a larger amount of energy being released from the steam onto your hand. Both are at the same temperature, but steam has a larger amount of energy because it undergoes the phase change of vaporization, which requires heat to be added to the system. Therefore, steam contains much more energy than water, which results in more heat coming into contact with your hand.

[Sondia Luong 1C]

Steam burns more because as it cools down to the same temperature of your skin, it releases more energy compared to when water spills on you.

[Brandon McClelland3L]

The short answer is that it's because steam has more energy. This is because although the temperature isn't different between water and steam, the heat of vaporization to turn water into steam is a lot.

[Mina Tadros 3L]

Steam burns at 100 degrees Celcius are more severe than water burns at 100 degrees Celcius because you have to consider the amount of energy required for the phase change. Thus, when steam begins to condense when it touches a colder surface, you have to add the energy released from the phase change to the energy released when the temperature is lowered.

[Neel Sharma 3F]

Steam burns worse than water at 100 degrees celsius because the heat of vaporization that the steam is releasing when it makes contact with the skin is far greater than the enthalpy change water makes when it makes contact with the skin. A heating/phase change diagram shows this relationship very well. Hope this helps!

[Jack_Pearce_2H]

The enthalpy of vaporization is higher than that of fusion, so more energy is released when steam goes to water than when water loses heat and stays in the same phase. Also, steam first has to lose heat if it is above 100 C and then phase change, again transferring more heat and causing larger burns.

[arisawaters2D]

Steam causes more severe burns because steam holds more heat energy at 100 degrees Celsius than water at the same temperature since the phase change from liquid to vapor requires a large amount of energy.

thank you! this makes a lot of sense

[Sejal Parsi 3K]

Water has a higher enthalpy of vaporization because of its hydrogen bonds, so when these bonds re-form, they release heat, creating the burns.

[Geethika Janga 1L]

Steam causes more severe burns to the skin than water because when it contains more energy than water at 100C due to the phase change form liquid to vapor. When it touches your skin, it releases that energy, essentially going from vapor back to liquid form and that expels a lot of heat energy.

[Jaden Kwon 3C]

I think it's because the enthalpy of vaporization/condensation is high which means that even if steam and water are the same temperature, more energy is released and transferred to your skin with steam than with water because the steam has to overcome that high enthalpy of vaporization/condensation in addition to cooling down.

[Gicelle Rubin 1E]

The steam causes more severe burns because of the large amount of energy it takes to turn liquid water into steam. If you think about the steam as condensing when it hits your skin, then the steam must release all the energy it took to phase change into vapor, and therefore it releases a lot of heat energy onto your skin. In contrast, boiling water will decrease in temperature, but it does not have to release the energy of that phase change, so the burns are less severe.

Thanks, it makes sense! :)

[Katie Le 3K]

The steam would burn at 100 C compared to water at 100 C because steam has more energy than water at 100C. That energy transfer from the steam to hand releases heat.

[Andrew Yoon 3L]

Thank you everyone for responding! I understand it now! :)

[rhettfarmer-3H]

I think the best way to think of the reason steam causes more damage is by looking at the heat change of water graph. Hence, when we look at it the phase change to L to G is way higher in temp and energy than S to L. Therefore, when steam hits you more energy is used to lower the temp back down the curve. Whereas, the liquid is less. Hence, it hurts more.

[rhettfarmer-3H]

I think the best way to think of this is with the graph of water. So, looking at the curve you see that energy is on the y axis. So S to L is the first state of mater change. THen L to gas. Each takes more and more energy. S to L takes less energy than L to G because the molecular of a solid is compact and gas is very free. hence, when steam hits you it holds more energy and therefore more thermal energy than liquid.

[Neel Sharma 3F]

Steam burns more than water at 100 C as when it makes contact with your skin it has to cool off. When looking at the phase change diagram, we see that it releases a lot more heat (around 40 kJ) as opposed to water when cooling. This extra heat makes the burn far more painful. Hope this helps!

[kentbui1d]

The steam first has to give off the enthalpy of vaporization before it can start to cool down to the temperature of your skin (transferring heat while it is cooling down).

[Katelynn Shaheen 2C]

Steam holds and releases more heat energy than the liquid form of water and therefore, causes more severe burns.

[Griffin G]

Steam will do more damage because there is more energy in the steam than in liquid water of the same temperature.

[Lindsey Walter 3E]

Steam causes more burns at the same temperature as water because steam will hold more energy than water at that temperature.