Measurements

Unit1

Measurements

Learning Objectives

* Able to understand the need for measurement in our life.

* Able to define length, mass, time and volume.

* Able to evaluate the values of some physical quantities in terms of their units and sub units.

* Able to identify zero error and parallax error.

* Able to measure the volume of solids and liquids.

* Able to construct their own measuring tools (models)

Few Questions to start with:

* Your cousin asks you what your height is. How will you measure and inform him?

• I measure my height using meter scale. And inform my height in cm. 

* Your friends decide to play kabbadi. How will you measure and draw the border lines?

• I measure and draw the border lines by feet.

* Your father gives you a bag and asks you to get potatoes. How will you ask the shopkeeper? A bag full of potatoes or how will you ask? 

• I ask the shopkeeper in kilogram.

* Your mom daily gets milk from the milk man. How much does she get? A cup of milk or two tumblers of milk or how?

• My mom daily gets milk from the milkman by liters.

* How long will it take to reach your school from your house?

• To reach my school from my house it will take 30 minutes

* How does the shopkeeper measure kerosene while selling it?

• The shopkeeper measures kerosene by liter while selling it.

Introduction

We have already heard about the words like weight, kilogram, litres, millilitres, kilometre, length, distance etc. In this chapter let’s have a deeper look at length, weight, volume and time and the necessity to measure them. To do the tasks given above we need to know about measurement. The comparison of unknown quantities with some known quantities is known as measurement. Measurement of a quantity has two parts: a number and its unit.

What are the measuring tools that you know?

Which of these tools will you use to do the tasks listed above and the similar ones?

Measuring Tools