Air refers to the Earth‘s atmosphere.
Water vapor in the air is sometimes visible as clouds. Water enters the atmosphere through the water cycle. The water cycle also brings molecules in the air into oceans, lakes, and rivers.
The air is different as you move higher and higher into the atmosphere. The air gets “thinner” as elevation climbs because there are fewer air molecules up there. Mountain climbers often have to use canisters of oxygen as they climb above 3,800 meters (12,500 feet) because there is not enough oxygen in the atmosphere for most people to breathe. High mountains such as Mount Everest (8,848 meters or 29,035 feet), in Nepal and China, are littered with empty oxygen canisters that climbers discard when they are used up.
Air is the clear gas in which living things live and breathe.
Air is a mixture of about 78% of nitrogen, 21% of oxygen, 0.9% of argon, 0.04% of carbon dioxide, and very small amounts of other gases.
The third layer of air is called the mesosphere. This layer can be found over 52 kilometres (32 miles) above the earths’ surface. The upper part of the mesosphere is called the mesopause. Within the mesosphere, temperatures are decreasing once more. Mesosphere temperatures are around -90 °C (-130 °F).
The weight of air creates atmospheric pressure.
Animals live and need to breathe the oxygen in the air. In breathing, the lungs put oxygen into the blood, and send back carbon dioxide to the air. Plants need the carbon dioxide in the air to live. They give off the oxygen that we breathe. Without it we die of asphyxia.
There is no air in outer space.
Air is not only located on earth, it is also located around the earth in an air layer called the atmosphere. The atmosphere can be divided up in separate layers depending on temperature and height. These lines are not clearly separated by straight borders – they gradually overflow one another.
It is a mixture of many gases and tiny dust particles.
The first layer of air, which is located closest to the earth is called the troposphere. This layer is 11 kilometres (7 miles) in height. When moving up in the troposphere temperatures fall 6 or 7 degrees per kilometre.
It has an indefinite shape and volume. It has mass and weight, because it is matter.
The second layer of air above the troposphere is called stratosphere. Temperatures stop decreasing in the lower part of this layer. The temperature is around -55 °C (-67 °F) here.
Air is one of the four classical elements along with water, earth and fire in ancient Greek philosophy and in Western alchemy.
Air can be found everywhere on earth exept where there is water. Air is even located in the surface layer of the earth – in the soil.