Earth's Atmosphere

Key Stage 3

Meaning

Earth's Atmosphere is a mixture of gases covering the surface of the Earth.

About the Earth's Atmosphere


A Pie Chart showing the percentage of different gass in the Earth's Atmosphere.

The Earth's Atmosphere is essential to the survival of many living creatures on the planet.

The Earth's Atmosphere has not always had the same proportions of gases. 3.9 billion years ago there was no Oxygen in the atmosphere. In the last 200 years humans have caused the Carbon Dioxide in the Earth's Atmosphere to double.

Key Stage 4

Meaning

Earth's Atmosphere is a mixture of gases covering the surface of the Earth.

About the Earth's Atmosphere

The Earth's Atmosphere is around 79% Nitrogen, 20% Oxygen 1% Argon and 0.04% Carbon Dioxide. However, these percentages vary depending on the humidity as Water Vapour can make up some of the Earth's Atmosphere.

The Earth's Atmosphere insulates the Earth keeping the surface at a higher average temperature than if it did not have an atmosphere.

The Earth's Atmosphere protects organisms on the surface from harmful cosmic rays and solar wind.

Formation of the Earth's Atmosphere

The Earth's Atmosphere formed 3.9 billion years ago.

Scientists believe the Earth's Atmosphere was formed from gases released from Volcanoes on the early Earth.

Gas from the early Earth has been trapped in small bubbles in volcanic rock showing it be mostly Carbon Dioxide, Methane and Nitrogen. Some evidence also suggests there may have been high quantities of ammonia.

If there had been any Oxygen in the early atmosphere it would have reacted with the Methane to produce Carbon Dioxide and Water or any reactive metals to produce metal oxides.

Evolution of the Earth's Atmosphere

Once organisms evolved which could get energy from sunlight via photosynthesis the Carbon Dioxide in the atmosphere decreased and Oxygen began to increase.

Carbon Dioxide was also removed from the atmosphere when it dissolved in the ocean and was used by some sea organisms to form hard Calcium Carbonate shells.

Extra Information

Equilibrium of the Earth's Atmosphere

The amount of different gases in the atmosphere have remained roughly the same for the last 3 million years due to a balance of processes which either add gases to the atmosphere or remove it, including the carbon cycle and the nitrogen cycle (higher tier).

Carbon Dioxide is constantly produced by volcanoes, combustion and respiration, but it is removed from the atmosphere by photosynthesis and dissolving in the ocean.

Oxygen is constantly produced by photosynthesis but removed by combustion and respiration.

Human effects on the Atmosphere

The equilibrium of gases has been affected by combustion and other industrial processes caused by humans.

Before the industrial revolution the amount of Carbon Dioxide in the atmosphere was 0.02%. Since then, due to the combustion of fossil fuels it has increased to 0.04% which scientists believe is causing the average global temperature to increase.