Various techniques have been devised to permit the analysis of the structure and function of microorganisms. Some techniques are qualitative in their intent. That is, they provide a "yes or no" answer. Other techniques are quantitative in their intent. These techniques provide numerical information about a sample.

Assessing the growth of a bacterial sample provides examples of both types of analysis techniques. An example of a qualitative technique would be the growth of a bacterial sample on a solid growth medium, in order to solely assess whether the bacteria in the sample are living or dead. An example of a quantitative technique is the use of that solid growth media to calculate the actual number of living bacteria in a sample.

Microscopic observation of microorganisms can reveal a wealth of qualitative information. The observation of a suspension of...