Volcanic eruptions released gases from within the Earth that collected in the atmosphere over millions of years to form the air we breathe. As the young planet cooled, thick clouds developed and heavy rains formed the oceans, which absorbed much of the carbon dioxide. Tiny ocean plants then began producing oxygen through photosynthesis, enriching the atmosphere with the nitrogen and oxygen that now dominate air and support life.

1. Air around us
Air is all around us. It is a mixture of invisible gases, mainly nitrogen and oxygen.
People, animals and plants need these gases to live. So if there was no air, there would be
no life on earth.
How did the atmosphere form?
The air around the earth is called the atmosphere. It was formed a long time ago when the
planet was very young. Back then, there were many volcanoes. The volcanoes erupted,
sending out think of steam and other gases that had been trapped inside earth. The stream
turned into violent storm clouds that rained down on earth to form the oceans. The gases
collected just above the planet. Over millions of years they have changed into the air we
breathe today.
How air was made?
• Volcanoes erupted, sending gases out of earth. They formed a chick blanket of
carbon dioxide, nitrogen and water vapor around the hot planet.
• As earth cooled, think clouds developed. Many years of rain formed the oceans.
The seas absorbed most of the carbon dioxide. The atmosphere was now mainly
nitrogen gas.
• Tiny plants called algae developed in the oceans. They used carbon dioxide and
sunlight to make food. They gave off oxygen, which collected in the atmosphere.
Thus, air was formed. It is rich in nitrogen and oxygen. It has small amounts of
other gases, like carbon dioxide, besides dust and water vapor.
• Iceland, located on a hotbed of underground volcanic activity, uses the
geothermal energy to heat 90% of its buildings.
• September 2002 India is the world’s fifth largest generator of wind and solar
power.