Final answer:
Density is a crucial physical property that can help identify the composition of an object. Each substance has a characteristic density, which allows differentiation between substances such as gold, iron, and aluminum. When objects are made of multiple materials, additional information besides average density is needed for accurate identification.
Step-by-step explanation:
The density of an object can often be used as a hint in identifying the substance from which it is made. Density is defined as the mass of an object divided by its volume and has units typically expressed as grams per cubic centimeter (g/cm3) or kilograms per cubic meter (kg/m3). Since each substance has a characteristic density, knowing the density of an object can help to pinpoint what material it is composed of.
For example, the density of gold is significantly different from that of iron, which in turn is different from aluminum. Thus, if an object's density is approximately 19.3 g/cm3, one could infer that the object is made of gold. However, when an object is composed of more than one material, additional information is necessary to identify the various substances it contains.
Density is particularly important not only in identifying materials but also in determining how objects will behave in a fluid. An object will float if its density is less than the density of the fluid, and it will sink if its density is greater. Additionally, dimensional analysis can be employed using an object's density to solve for an unknown mass or volume.