Latent heat of fusion of ice

Latent heat of fusion (L) is the heat per unit mass required to convert a solid into a liquid at it melting point.

Formula L = Q/m

L is measured in J/g or J/kg

This video describes a simple experiment that allows to estimate the latent heat of fusion of ice.

Ice close to its melting point of 0 degrees Celsius is mixed with water at room temperature. (This is often done to cool drinks). By measuring the final temperature of the mixture, the latent heat L can be calculated.

The calculations are based on the assumption that the heat lost by the water in the cup is gained by ice which first melts and then the resulting water at 0 degrees Celsius warms up until it reaches thermal equilibrium with the water which was initially in the cup. In reality, the ice takes in heat not only from the existing water but also from the surroundings (the room temperature was around 23 degrees C). Also, it is possible that the ice was at a couple of degrees below zero. All in all, this method is not extremely accurate and it is based on some optimistic assumptions but, nevertheless, it provides the correct order of magnitude for the latent heat.

The accepted value of the latent heat of fusion of ice is 334 J/g or 3.34 x 10^5 J/kg