Introduction to Scalers

Physical quantities such as time, mass, and distance have magnitude, but no direction. Such quantities are called scalar quantities.

They are expressed as a numerical value followed by a physical unit. For example, the mass of an apple is 100 g. 

Scalars are different from vectors as vectors have both magnitude and direction.

For example, the mass of an object depends on the amount of matter in a substance and is a scalar quantity.  In contrast, its weight, which is the force exerted due to the Earth’s gravity, is a vector quantity.

Similarly, distance is a scalar quantity, while displacement, which is the change in the position of an object, is a vector quantity.

Scalars are denoted with italicized letters.

Scalars can be negative such as the charge of an electron or the reading of a thermometer scale.

Here, the minus sign represents the point on a scale or nature of the entity.

For Celsius and Fahrenheit thermometers, scales read zero at different points. Hence, the negative temperature also reads at different scale readings.