If you have the
number of milliliters, you can find grams by multiplying milliliters by the
density of the material. For example, if you had a rock with a volume
of 10 mL and a density of 5.5 g/mL, the mass will be 55 grams.
Because water has a density of 1.0 g/mL, the number of grams of water is
the same as the number of milliliters.