Quantity and Measurement

Measurement is the act of measuring something to find the quantity. By Measurement, we can determine the quantity of anything by comparing it to some other pre-defined standards.

For example, if you want to find how much is the mass of a solid steel ball, you can find it by comparing the steel ball by using a common balance and a pre-calibrated mass object. Refer below images.

To express measured quantity, you need two things. 1) a number and 2) a unit. Without the quantity expressed in number and a unit, measurement has no meaning.

For example; you want to measure the length of your mattress

You can measure the length of your Mattress by using a measuring tape. A common measuring tape has two sides. One side is marked in inches and other side in centimeters.

Consider the measured length is 203.5 centimeters. Here, 203.5 is the measured quantity in number and centimeters is the unit of measurement. If by mistake, instead of centimeters you write the unit as inches (or without a unit), the entire process of measurement will become useless.