4. The Composition Of Air

5. AIR IS MIXTURE OF GASES AIR Water vapour Other Gases Hydrogen Oxygen Carbon dioxide Nitrogen

7. Property No.1

8. Experiment:1  Take two balloons of the same size.Blow them up to the same size.Tie them horizontally on a staw as shown below.

9.  Now burst one of them by pricking it with a needle.  What do you see ?  You will see that this end of straw goes up.

10. Property No.2

11. Take a bucket filled with water.Push a narrow mouth bottle in to the water.

12. . You will see bubbles of water escaping from the bottle and water entering in to bottle. These bubbles are air which escape from the bottle while water entering in bottle

13. Property No.3 Air occupies space

14. Fix a candle in a basin and half filled water Light the candle. Experiment No. 2

15. immerse a cylinder over the candle

17. .  What do you see?  W Water level rises up one fifth of volume of cylinder TThis shows that propotion of oxygen in air is about one fifth.

21. Breathing

22. Aquatic animals too need Oxygen

23. Plants too need carbondioxide of air for breathing.

24. Reviewing The Lesson There is an envelope of air surrounding the earth called atmosphere. Properties of Air: 1. Air is colourless. 2. Air has mass. 3. Air occupies space. Uses of Air: 1. Breathing (humanbeing,animals,plants) 2.Burning. Other uses of Air: Sailboat, windmill, Cycle tube, football,

25. Burning Oxygen is necessary for the burning of all sbstances like wood,coal, paper,etc.No substances can burn in the absence of oxygen.

27. OXYGEN A sailboat acquire the motion of the wind and moves speedily on water.

28. A windmill can be used to draw water from the well and to generate electricity.

29. Mountaineer carry oxygen cylinder while climbing on high altitude of mountains.

31. Cycle tube filled with enough air therefore it is easy to ride the bicycle.

32. A foot ball Filled with air Can move Easily.