Class-6, air around us. composition of air.

1. “ An open mind is like an open window. It lets the fresh air in.”

2. • Do ever wondered what happens
while we breathe?
• Can you tell what happens when
we turn on fan, cooler or AC
during summer? Why we need
them?
• What do you think actually air is?
• What can be the compositions of
air?
• What do you think would happen
if there is no air present?
• Have you ever played with firki or
kite?

3. Air Around Us
Abinash Naik
B.Sc, B.Ed CBZ
51

4. What is air?
• Air is the invisible mixture of gases that
forms a blanket which surrounds the
Earth can be called as the Earth’s
atmosphere.
• And atmosphere is the envelop of gases
that surrounds a planet(such as Earth).
• Around in Earth’s atmosphere can be
found everywhere.
• Although we can’t see air, we can feel
it.

5. Different Layers of Earth Atmosphere
• Troposphere: Earth’s troposphere extends from Earth’s surface to, on average, about 12
kilometers (7.5 miles) in height, with its height lower at Earth’s poles and
higher at the equator.
• Stratosphere: Located between approximately 12 and 50 kilometers (7.5 and 31 miles)
above Earth’s surface, the stratosphere is perhaps best known as home to
Earth’s ozone layer, which protects us from the Sun’s harmful ultraviolet
radiation.
• Mesosphere: Located between about 50 and 80 kilometers (31 and 50 miles) above Earth’s
surface, the mesosphere gets progressively colder with altitude.
• Thermosphere: The layer of very rare air above the mesosphere is called the
thermosphere. Many satellite actually orbit Earth within the thermosphere.
• Exosphere: Although some experts consider the thermosphere to be the uppermost layer of
our atmosphere, others consider the exosphere to be the “final frontier” of
Earth’s gaseous envelope. Air in exosphere is very thin.

6. What is air made up of?
• Until early eighteenth century people thought that air was just one substance. Through
experimentation it was proved it is not just one substance.
• Actually air is a mixture of many gases.
• WATER VAPOUR: When water gets heated gets converted into water vapour and when water
vapour comes in contact cool surfaces it gets converted into water. Water vapour is essential for
water cycle.
• OXYGEN & NITROGENT: We know that air contains about 21% of Oxygen and about 78% of
Nitrogen in it. Oxygen is the key element that is essential to sustain life where Nitrogen used in
fertilizers. Oxygen supports burning where as Nitrogen doesn’t.
• Carbon dioxide and other gases: Carbon dioxide is the gas that is released when organic matter
such as wood is burned. These gases are mostly harmful and may cause suffocation when inhaled
too much.
• DUST AND SMOKE: When we burn something we see some black fumes comes out, those are
nothing but smoke. Some are harmful in nature and are release by factories in large amounts.
Dust are also the cause many allergies and cause many lung diseases. We often use masks to
protect ourselves from dust.