The freezing, then thawing, of three common refrigerator items—ice, butter, and cheese—will help solidify your understanding of partial melting.
Step 1. Mix cubes of ice, butter, and cheese together with a little water, and put this mixture in the freezer. Once this mixture has frozen, it will be your “rock.”
Step 2. Put this “rock” in a bowl in the refrigerator overnight, and then examine the contents of the bowl the next day.
(a) In this mixture: What melts? What doesn’t melt? How is the melt different from the original “rock”? Now let’s think about the partial melting of real rocks:
(b) What melts? What doesn’t melt? How is the melt different from the original rock? Now let’s consider the cooling and solidification of the melt:
(c) How are the first-formed igneous rocks different from the rock that originally melted?