What are the main components of the Earth's atmosphere?

The main components of the Earth's atmosphere are nitrogen, oxygen, argon, carbon dioxide, and trace gases.

The Earth's atmosphere is a complex mixture of gases that surrounds the planet, extending from the surface to more than 100 kilometres above. The most abundant gas in the atmosphere is nitrogen, making up about 78% of the total volume. Nitrogen is a crucial element for life as it is a key component of amino acids and proteins, which are the building blocks of life.

Oxygen is the second most abundant gas, accounting for approximately 21% of the atmosphere. Oxygen is essential for most forms of life because it is used in the process of respiration, where organisms convert food into energy. It is also involved in combustion reactions, such as fires and the burning of fossil fuels.

Argon, a noble gas, makes up about 0.93% of the atmosphere. It is chemically inert, meaning it does not readily react with other substances. This property makes argon useful in applications where reactions with other substances are undesirable, such as in light bulbs and welding.

Carbon dioxide (CO2) is a minor component of the atmosphere, making up about 0.04%, but it plays a significant role in Earth's climate. CO2 is a greenhouse gas, which means it absorbs and emits infrared radiation, contributing to the warming of the Earth's surface. The concentration of CO2 in the atmosphere has been increasing due to human activities, particularly the burning of fossil fuels, leading to global warming and climate change.

In addition to these main components, the atmosphere also contains trace amounts of other gases, including neon, helium, methane, krypton, and hydrogen, as well as water vapour. These gases make up less than 1% of the atmosphere but play important roles in various processes. For example, methane is a potent greenhouse gas, while water vapour is crucial for the formation of clouds and precipitation.