The volume of water is simple to calculate -- just pour it into a measuring cup. The volume of ice is a little trickier. When water freezes, it condenses and as it becomes ice its density lessens. If you are lucky enough to have a block of ice with perfectly straight edges, you can calculate its volume by multiplying its three dimensions together. For other forms of ice, the volume can be calculated through its weight and the known density of ice.

Weigh a bowl on the kitchen scale and write down the weight. For example, the bowl weighs 5 g.

Place the ice in the bowl. Subtract the weight of the bowl from the total weight to calculate the weight of the ice. For this example, the total weight is 8 g. Subtract 5 from 8 to get 3. The ice weighs 3 g.

Divide the weight by the density of ice. Ice has a density of 0.92 g/mL, so 3 grams divided by 0.92 grams per milliliter equals 3.26 mL. The volume of 3 grams of ice is 3.26 mL.