Test: Air Around Us

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases

The blowing wind makes the windmill to rotate.

The energy in which wind is used to generate electricity is known as wind energy. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power is then used for various purposes. Wind energy is a free and renewable resource. It is a clean and non-polluting source of energy.

Air is a mixture of a number of gases like Nitrogen, Oxygen and Carbon dioxide etc.

A weather cock shows the direction in which wind is blowing.

Mountaineers carry Oxygen cylinder with them, while climbing mountains because air pressure is low at higher altitude.

The nose and mouth of traffic police at the crossing is covered with masks due to the presence of high pollutants in air.

The presence of air around can be proved by feeling it when it moves.

The active part of air is Oxygen that help in combustion and respiration.

Gases used in welding and cutting processes include: shielding gases such as carbon dioxide, argon, helium, etc. fuel gases such as acetylene, propane, butane, etc. oxygen, used with fuel gases and also in small amounts in some shielding gas mixtures.

The burning of fossil fuels - like coal, oil and natural gas - releases gases into the air, mainly carbon dioxide, sulfur dioxide, methane and nitrous oxide.