Measurement

Unit 1

Measurement

Learning Objectives

After studying this unit, students will be able

* To identify fundamental and derived physical quantities.

* To identify fundamental and derived units.

* To obtain units for certain derived quantities.

* To measure the area and volume of some regular shaped and irregular shaped objects.

* To convert the volume of objects from cubic metre to litre and vice versa.

* To calculate the density of solids and liquids.

* To define Astronomical unit and light year.

Introduction:

How are the various articles and materials shown in the picture measured?

In day to day life, we measure many things such as the weight of fruits, vegetables, food grains, volume of liquids, temperature of the body, speed of the vehicles etc., Quantites such as mass, weight, distance, temperature, volume are called physical quantities.

A value and a unit are used to express the magnitude of a physical quantity. For example Suresh walks 2 kilometre everyday. In this example ‘2’ is the value and ‘kilometre’ is the unit used to express the magnitude of distance which is a physical quantity.