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Air Around Us .pptx
- 2. 1.YOU HAVE LEARNT THAT ALL LIVING THINGS NEED AIR. BUT CAN WE SEE AIR? 2.HOW DO WE KNOW THAT AIR IS PRESENT ALL AROUND US?
- 3. THE CLOTHES HANGING ON THE CLOTHES-LINE SWAY
- 4. FLUTTERING OF PAGES OF BOOKS
- 6. WIND YOU MIGHT HAVE SEEN TREES BEND WHEN WIND BLOWS. WHAT IS WIND ? MOVING AIR IS CALLED WIND.
- 7. AIR IS PRESENT ALL AROUND US ACTIVITY 1. 1.DIP THE OPEN MOUTH OF THE BOTTLE INTO THE BUCKET OR TOUGH FILLED WITH WATER. 2.NOW TILT THE BOTTLE SLIGHTLY. 3. AND OBSERVE WHAT HAPPEN. Q.CAN YOU SEE BUBBLES COMING OUT OF THE BOTTLE. Yes Q. CAN YOU GUESS WHAT WAS IN THE BOTTLE. ‘AIR’ WHAT WE HAVE LEARNT ? AIR OCCUPIES SPACE. AIR IS PRESENT ALL AROUND US AIR HAS NO COLOUR. AIR IS TRANSPARENT.
- 8. ATMOSPHERE Our earth is surrounded by a thin layer which extents up to many kilometers above the surface of the earth called atmosphere. ATMOSPHERE
- 9. Q why do mountaineers carry oxygen cylinder with them when they climb high mountains ? As we move higher in the atmosphere, the air gets thinner and thinner that is why there is less air in higher mountains that’s why the mountaineers carry oxygen cylinder when they climb high mountains.
- 10. WHAT IS AIR MADE UP OF ? Untill eighteen century, people thought that air was just one substance. So , what is air actually made up of ? Air is made up of many gases. They are -Water vapour -Oxygen -Nitrogen -Carbon dioxide - Dust and smoke
- 11. OXYGEN Activity-2 1. Fix two candles on the table 2. Light the candles. 3. Cover one of the candle with an inverted glass tumbler or bell jar. 4. Observe both the candle carefully. Q why the candle covered with glass tumbler or bell jar got extinguished ? - The candle got extinguished because the component of air which supports burning inside the tumbler or bell jar is limited that’s why it got extinguished .. Q what is the name of that component of air ? - oxygen
- 12. NITROGEN -Nitrogen is the major component of air. -Unlike oxygen, it does not support burning -Its takes up nearly 78 % of the air.
- 13. CARBON DIOXIDE -CARBONDIOXIDE MAKED UP A SMALL COMPONENT OF THE AIR AROUND US. -PLANTS AND ANIMALS CONSUME OXYGEN FOR RESPIRATION AND PRODUCE CARBON DIOXIDE. -PLANT AND ANIMAS MATTER ALSO CONSUMES OXYGEN ON BURNING AND PRODUCES MAINLY CARBON DIOXIDE AND FEW OTHER GASES.
- 14. WATER VAPOUR Q. From where the water droplets on the outer surface of the glass tumbler comes from? When the water vapour present in air comes in contact with the cooled outer surface of the glass tumbler the water vapour condenses and drops of water appear on the outer surface of glass tumbler. Therefore water vapour is present in air. WATER DROPLETS
- 15. DUST AND SMOKE -The burning of matter produces smoke also. -Smoke contains a few gases and fine dust particles and is also harmful. Q why we see long chimneys in factories ? The long chimneys in factories take away the harmful smoke from our noses.
- 16. Exercise I 1.Which gas in the atmosphere is essential for respiration? Nitrogen oxygen carbon dioxide argon 2. Air in motion is called? atmosphere oxygen wind nitrogen 3.The layer of air around the earth is ? Atmosphere hydrosphere lithosphere space 2 1 4 3 2 1 4 3 2 1 4 3