At a glance - Air

• Earth is surrounded by a blanket of air called the atmosphere.

• Atmosphere has different layers.

• Air is a mixture of nitrogen, oxygen, carbon dioxide,water vapour and other gases such as argon, neon, helium,etc.

• Air exerts pressure known as atmospheric pressure.

• Air rushes from a high pressure area to a low pressure area.

• A barometer is an instrument used to measure atmospheric pressure.

• A space without air is called a vacuum.

• Land and sea breezes are caused due to the difference in air pressure.

• When air expands, it rises up.When air contracts, it comes down.