The About.com chemistry section identifies hundreds of different kinds of scientists. For example, an actinologist is a person who studies the effect of light on chemicals, while an actinobiologist studies the effects of radiation on living things. Bacteriology is the study of bacteria, and climatology is the study of climate and its effects. Almost every letter of the alphabet is associated with at least one area of scientific study.
According to Dictionary.com, a science is defined as a branch of knowledge pertaining to scientific investigation, or the study of a body of scientific facts. Science is based on truths, which are systematically arranged: These scientific facts explain the operation of general laws.
A definition for a branch of science is somewhat more broad: It is the systematic order of physical or material elements, which are explained through scientific observations and experimentation. In other words, a branch of science represents physical phenomenon that can be seen, measured and observed in a systematic way.
As human knowledge of the Universe becomes more extensive and complex, the number of areas of scientific inquiry expands. As of 2014, Phrontistery identifies 633 separate areas of study that it refers to as scientific. These areas range from well-known sciences, such as biology and astronomy, to many that are quite obscure. Almost all of these scientific areas of study end in "-ology," meaning a branch of knowledge or subject of study.