Physics is interested in expressing the real world in mathematical terms. The first step in this process is to understand the difference between a scalar and a vector. These two categories can be distinguished from one another by their distinct definitions: Scalars are quantities that are fully described by a magnitude (or numerical value) alone. Vectors are quantities that are fully described by both a magnitude and a direction.

Scalars are quantities that are fully described by a magnitude (or numerical value) alone. Example: Temperature Note: Temperature has no direction. It is not 57oC up, or 25oF to the left!