Define a scalar quantity as a quantity with magnitude only.

A scalar quantity is defined as a physical quantity that has only magnitude, meaning it can be described by a numerical value alone without any reference to direction. Examples of scalar quantities include mass, temperature, and energy. These quantities can be added, subtracted, or averaged without concern for direction, as they do not possess any directional component. Understanding the distinction between scalar and vector quantities is crucial in physics, as it helps in accurately describing and analyzing physical phenomena.