Fusion is the melting of ice and vaporization is the boiling of water.
In this lab there are two different experiments. The first is the affect on the temperature of a cup of water when fusion of ice occurs in it. Using a razor blade cut off about a quarter inch off of the tops of the other two cups, the cut cups should be able to fit inside the labled cups when turned upside down. Poke a hole in each of the cut cups big enough so that the thermometers can fit through them. Measure the weight of one set of cups then fill the bottom cup labled B about half way with water and reweigh recording both weights.