rephrase please

The density of objects is defined as the ratio of the object's mass to its volume. Density is a characteristic property of the kind of mass but is not a unique characteristic. That is, more than two kinds of matter may have the same density and in the cases of solutions, mixtures, alloys, etc, common densities occur often.

The purpose of this exercise is to determine the density of several different types of metals by making mass and volume measurements. The physics laboratory makes extensive use of large number of different types of apparatus each requiring a thorough knowledge of how the equipment operates and what its capabilities and limitations are. In this exercise, measurements will be made of length, mass, and time and the results used to determine the density of several different objects.