Asked by: Ray Pinkerton

The first variable is dependent on the type of material you wish to melt, and is called the heat of fusion 'L'. For ice, L is = 335 kJ/kg.

The next variable is the mass 'm' of the material you wish to melt measured in kg.

The last variable is the effect 'p' at which heat is transferred to the material, measured in watt (W).

Now lets try an example. If I wish to determine how much time 't' it will take to melt two kilos of ice on a stow at 1000 W, i will have to use the following expression:

t = Lï¿½m / p

t = 335000 J/kg ï¿½ 2 kg / 1000 W

t = 670 seconds = 11.2 minutes.

This example is, of course, 100% theoretical and does probably not apply to reality.

Answered by:
Lars Krebs, Student, Aalborg Technical Collage, Denmark

'For the sake of persons of ... different types, scientific truth should be presented in different forms, and should be regarded as equally scientific, whether it appears in the robust form and the vivid coloring of a physical illustration, or in the tenuity and paleness of a symbolic expression.'**James Clerk Maxwell**

(*1831-1879*)