CHAPTER 15 AIRCLASS VI

AIR IS PRESENT EVERY WHERE AROUND US.

• MOVING AIR IS CALLED WIND.

• ACTIVITY:• An empty bottle is inverted and dipped under

water. • Water does not enter inside bottle because the

space inside the bottle is filled with air.• On tilting, air goes out of the bottle.Now water

enters the bottle. • AIR OCCUPIES SPACE

PROPERTIES OF AIR• AIR HAS NO COLOUR. IT IS TRANSPARENT.• THE ENVELOPE OF AIR AROUND EARTH IS

CALLED ATMOSPHERE.

ATMOSPHERE

• As we go higher and higher, above the suface of earth, the thickness of air becomes less .

• At the top of high mountains, oxygen is less.

• Mountaineers carry oxygen cylinders with them.

• AIR IS A MIXTURE OF GASES.

COMPOSITION OF AIR - * NITROGEN -78% * OXYGEN -21% * CARBONDIOXIDE - 0.04% * WATER VAPOUR * DUST &SMOKE

OTHER S

WATER VAPOURWATER VAPOUR IN AIR IS AN IMPORTANT PART

OF WATER CYCLE

OXYGEN

• HELPS IN BURNING • ESSENTIAL FOR BREATHING

• ACTIVITY:• TAKE WATER IN A CONTAINER

AND HEAT IT.

WE OBSERVE TINY BUBBLES ON THE SURFACE OF VESSEL , AFTER SOME TIME.

THESE BUBBLES COME FROM AIR DISSOLVED IN WATER.

• OXYGEN DISSOLVED IN WATER IS USED BY AQUATIC ORGANISMS

• OXYGEN PRESENT IN AIR IN BETWEEN SOIL PARTICLES IS USED BY SOIL ORGANISMS.

• EARTHWORMS COME OUT OF THEIR BURROWS DURING RAIN .

WATER occupis all spce in between the soil particles ,replacing air.Eatrh worms find it difficult to breath.

AIR IS ESSENTIAL FOR BURNINGACTIVITY:

NITROGEN

• NITROGEN DOES NOT SUPPORT BURNING.• IT IS AN IMPORTANT PLANT NUTRIENT.

CARBONDIOXIDE

• RELEASED IN THE ATMOSPHERE DURING RESPIRATION ,BURNING, DECOMPOSITION etc.

CARBONDIOXIDE• USED BY PLANTS FOR PHOTOSYNTHESIS.

CARBONDIOXIDE• IT CAN EXTINGUISH FIRE.

DUST

• DUST PARTICLES ARE PRESENT IN AIR.

• Hairs present in nasal cavity prevent the dust particles from entering into the respiratory system.

SMOKE

• RELEASED BY VEHICLES, FACTORIES, KITCHEN BURNING OF OTHER MATERIALS.• CONTAIN HARMFUL GASES LIKE , OXIDES OF

NITROGEN, SULPHUR, CARBON etc.

• LONG CHIMNEYS OF FACTORIES TAKES THIS SMOKE AWAY FROM US BUT BRING IT CLOSER TO THE BIRDS.

OXYGEN CYCLE

PHOTOSYNTHESISRESPIRATION

[OXYGEN][CARBONDIOXIDE]

USES of AIR

FILL IN THE BLANKS• 1.AIR IS A ----------------------OF GASES.• 2.THE ENVELOPE OF AIR AROUND EARTH IS--------------.• 3.THE MAJOR CONTENT OF AIR IS -----------------GAS.• 4. --------------------GAS IS ESSENTIAL FOR BURNING.• 5. THE GAS USED FOR PHOTOSYNTHESIS IS -----------------.• 6.EARTH WORM BREATH AIR PRESENT IN ------------• 7.FISHES BREATH OXYGEN PRESENT IN --------------.• 8.---------------------------GAS CAN EXTINGUISH FIRE.

MIXTURE ATMOSPHERE

NITROGENOXYGEN

CARBONDIOXIDE

SOIL

WATERCARBONDIOXIDE

SAY TRUE OR FALSE• 1.MOVING AIR IS CALLED WIND.• 2.AIR DOES NOT NEED SPCE TO OCCUPY.• 3.CARBONDIOXIDE SUPPORTS BURNING . 4. EARTHWORMS BREATHE AIR PRESENT IN SOIL.

• 5. PLANTS AND ANIMALS DEPEND ON EACH

OTHER FOR EXCHANGE OF OXYGEN AND CARBONDIOXIDE FROM AIR.

6.HAIRS INSIDE THE NASALCAVITY FILTER CARBONDIOXIDE PRESENT IN AIR.

TRUEFALSE

FALSE

FALSE

TRUE

TRUE