Question

if temperature is constant during vapourisation then how does steam cause better burns in comparison of water at 100 c.

Answer 1

• Whenever any hot fluid (water or steam) comes in contact with any part of our skin, then it loses its heat energy to that part of skin. The more is the heat energy lost by the fluid, more is the burning effect caused by it.
• The boiling point of water is 100^oC. At this temperature, water will begin to change from liquid state to gas state. . In order for this change to take place, additional energy is required. This additional energy which converts water at 100^oC to steam is known as latent energy of vaporisation. During the conversion process, temperature does not increase. Therefore, both liquid water and steam exist at 100 ^oC. While they both would exist at the same temperature, the steam particles i.e water vapours would have a lot more heat energy than liquid water at 100 ^oC because water vapours have absorbed extra energy in the form of latent heat of vapourisation.
• When boiling water comes in contact with the skin then burning is caused due to release of all heat energy by boiling water.
• When steam comes in contact with skin then first it loses its extra latent heat to the skin and gets condensed to liquid water at 100 ^oC which is boliling water. Then this boiling water will release all its heat energy to the skin.

Since steam has released more heat energy therefore it causes more burning in comparison to boiling water.