Density of Solids:
The density of a solid is measured in terms of number of kilograms contained in a cubic meter. That is, density is equivalent to mass divided by the volume. The kilogram per meter cubed (kg/m3 or kg . m-3) is the measure of density in the International System (SI). It is an instead awkward unit in most real-life circumstances. Visualize trying to determine the density of sandstone by taking a cubical chunk of the stuff measuring 1 m on an edge and placing it on a laboratory scale! You'd require a construction crane to lift the boulder, and it would shatter the scale.
Since of the impracticality of measuring density directly in standard international units, centimeter-gram-second (cgs) unit is at times used rather. This is the number of grams contained in 1 cubic centimeter (cm3) of the material in question. Theoretically, it is known as the gram per centimeter cubed (g/cm3 or g . cm-3). To convert from grams per centimeter cubed to kilograms per meter cubed, multiply by 1,000. In opposition, multiply by 0.001.
You certainly can think of solids which are tremendously dense, like lead. Iron is quite dense also. Aluminum is not so dense. Rocks are less dense than most of the common metals. Glass is around the same density as silicate rock, from which it is made. The wood and most plastics are not very dense.
PROBLEM:
A sample of solid matter has a mass of 0.543 kg and a volume of 45.3 cm3. Compute the density in grams per centimeter cubed?
SOLUTION:
This trouble is a little tricky as two dissimilar systems of units are used, the SI for volume and cgs for the mass. To obtain a meaningful answer, we should be consistent with our units. The problem needs that we state the answer in the cgs system; therefore we convert kilograms into grams. This means that we have to multiply the mass figure by 1,000, that tells us that the sample mass is 543 g. Establishing the density in grams per centimeter cubed is now an easy arithmetic problem: Divide the mass by the volume. When d is density, m is mass, and v is volume then,
d = m/v
In this situation,
d = 543/45.3 = 12.0 g/cm3
This outcome is rounded to three significant figures.