Question

What is the amount of heat input to your skin when it receives the heat released (a) by of steam initially at , when it is cooled to skin temperature ()? (b) By of water initially at , when it is cooled to ? (c) What does this tell you about the relative severity of burns from steam versus burns from hot water?

Short answer

1. 
   
2. 
   
3. Steam burns more than boiling water

Step-by-step solution

Equation of heat flow

The equation of heat flow for a body of mass , specific heat capacity and for a temperature change of is .

Calculate the heat released for vapour to liquid transition

Given that , and .

Cooling the steam by the skin to means that there is a phase change from vapour to liquid. The heat transfer to the skin will be

So, the skin will gain a heat of .

Calculate the heat released from water only

Given that , and .

There is no phase change in the water so the heat transfer to the skin will be employed by

The heat gained by skin from water will be .

Compare the heat energies

From the above results, it is obtained that the heat release from the steam is higher than that released by the boiling water. So, the steam burns more than water.