Page 123 - Science Class 6 Times Publication

Nitrogen occupies 78.1% of the total volume of air. In the same way,
oxygen occupies 20.9% of the total volume. Carbon dioxide occupies
0.03% of the total volume of Air. Except these gases, there are
other gases like inert gases, water vapour, sulphur dioxide, carbon

monoxide etc. Gases like helium, argon, neon, krypton, etc do not
take part in chemical reaction. These gases are called inert gases.

Oxgen

It is one of the most important gases present in the air. It occupies
20.8% of the total volume of air. It is life gas for living things because
living things cannot survive without oxygen. All living things use

oxygen for breathing. Oxygen is used for burning of rewood, petrol,
diesel, coal, etc to produce heat energy. Oxygen is used to carry out

various types of chemical reactions. Oxygen in cylinder is used for
the treatment of serious types of patients. Mountaineers take oxygen
cylinder to breathe in higher altitude.

Activity 11.1

To prove that air contains water vapour

Materials required: A candle, a plate, big vessel, bell jar, etc.

Procedure

1. Take a candle and x it on a small plate.
2. Keep a plate over water kept in a bigger vessel.

3. Burn the candle and cover it with a bell jar and cover its
mouth. What happens?

Times' Crucial Science and Environment 119 Book 6