Page 3 - 3-Lesson Notes-Composition of air, Nitrogen, oxygen and Carbon dioxide

Activity: - To show the presence of air in the soil.

Materials required – Soil, jar, and water.

Procedure- Take dry lumps of soil in a jar. Add water to it.

Observation-We will see some bubbles come out from the soil surface.

Inference-This experiment proves that soil contains air.

Carbon Dioxide-
❖ Carbon dioxide is present in a very small amount in the atmosphere. The atmosphere
contains about 0.03% of carbon dioxide. Plants take in carbon dioxide present in the
air and release oxygen into the atmosphere. Plants use CO2 to synthesize food by the
process of photosynthesis.
❖ Carbon dioxide is also responsible for trapping the sun’s heat and is responsible for
the greenhouse effect.
❖ It can be liquified. It can also be solidified at low temperatures to form dry ice. It is
called dry ice because it converts into vapours without melting. It is used as a
refrigerant.
❖ It is moderately soluble in water, hence it is used for carbonation of soft drinks.
❖ It is used to manufacture urea.
❖ It does not support combustion, hence is also used as a fire extinguisher.
❖ On burning, plant and animal matter consume oxygen and mainly release CO2 in the
atmosphere along with a few other gases.

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