Measurements

Measurement is a basic skill which forms an essential part of day to day activities. Measurement is defines as a counting of the number of times a chosen scale is used.

The result of measurement of a physical quantity is expressed in terms of a value. The value of the physical quantity is equal to the product of the number of times the standard is used for the measurement and the quantity (the standard) defined for making the measurement. This defined or standard quantity (the scale used) is called a unit.

Value of physical quantity = numerical quantity x unit

A unit is a measure, device or a scale in terms of which we make physical measurement. The value of a physical quantity consists of two parts - a numerical quantity and a unit and is equal to their product.

Thus, it is necessary to state the numerical quantity as well as the unit while expressing the result of a measurement.

Characteristics of a Unit

A unit should be relevant for the quantity being measured. For example, distance cannot be measured in terms of kilogram. For example, it is not convenient to express the distance between two cities in inches.

Further, the unit used should be convenient also. In addition to being relevant and convenient a unit should also be well defined i.e. it should be well understood by other people. For example, you may express the distance between my house and a nearby shop as 200 steps. In order to make some sense, you need to define the step - whether it is my step or an adult and child. Is it while walking slowly or while running fast?

To be useful, a unit must be:

1. relevant
2. convenient
3. well defined

In today’s world, an accurate measurement is a necessary.