Page 122 - Science Class 6 Times Publication

Chapter
Chapter

11 AIR

Estimated periods: 6
OBJECTIVES

At the end of the lesson, the students will be able to :
Ü de ne air as the mixture of gases;

Ü tell and explain physical and chemical properties of air;
Ü explain about the main gases of the air and their importance.

MIND OPENERS
Ü Can you see air? How can you say that there is air around us?
Ü What are the components of air?
Ü What are physical properties of air?

Ü Why is air important?

Introduction

Our earth is surrounded by air. We cannot see the air but we can
feel its movement. The movement of leaves of plants, ying away of

clothes due to wind, etc show the presence of air.
Air is very important for living things. It contains various gases
which are essential for living things. These gases occupy following
percentage of total volume of air.
Gas Percentage by volume
Nitrogen 78.1%

Oxygen 20.9%
Carbon dioxide 0.03%
Inert gases 0.95%
Other gases 0.02%

Composition of air remains almost the same in all places. But it
differs in some places. The amount of carbon dioxide and water
vapour differs from place to place.

Times' Crucial Science and Environment 118 Book 6