Those who have ever read a chemistry or physical science book have probably come across the term density at some point. Density refers to the concentration of something in a particular area. As far as science is concerned, density is the term used to describe the measure of mass per unit of volume. Different substances vary in density and the differences in density determine how the substances interact with one another.

Review the simple mathematical formula for calculating the density of a substance, which is density = mass over volume or d=m/v. To use this formula, you will have to know the mass and the volume of the substance. The mass refers to the gravitational pull on the substance and how much matter it contains. The volume refers to the amount of three-dimensional space the substance occupies.

Calculate the volume of the substance by measuring the length, width and height. The formula looks like this: Volume = L (length) x W (width) x H (height).

Determine if the object or substance is irregularly shaped. If so, determine the volume by finding out how much water is displaced when the object is dropped into a beaker of water.

Calculate the density once you know the volume and mass of the substance or object. Density is equal to the mass of the substance divided by its volume: D (density) = M (mass) / V (volume).

Remember that a substance or object with a higher density has a higher measure of mass per unit of volume. A substance with a density that is greater than 1 gram/centimeter cubed will sink in water because it is denser. A substance with a density below 1 gram/centimeter cubed will float because it is less dense than water whose density is approximately 1 gram/centimeter cubed.