Earth is surrounded by a mixture of gases known as the Atmosphere

Composition of the Atmosphere Nitrogen – 78% Oxygen – 21% Other – 1% (Argon, CO2, Water Vapor, others)

Air Pressure Earth’s atmosphere is pulled towards Earth’s surface by gravity. Thus, the atmosphere is denser at the surface and less dense at higher altitudes.

Layers of the Atmosphere Troposphere- closest to the Earth’s surface. Where our weather occurs.

Layers of the Atmosphere Stratosphere – 2nd layer. Contains the Ozone layer.

Layers of the Atmosphere Mesosphere- 3rd layer, helps in protecting us from meteors.

Layers of the Atmosphere Thermosphere – Farthest from the Earth’s surface. Warmest layer, Interactions with solar radiation causes the aurora borealis.

Energy in the Atmosphere

Energy in the Atmosphere About 50 % of incoming solar energy is absorbed by Earth’s surfaces. About 50% is reflected back into space in the form of low level infrared radiation.

Energy Transfer in the Atmosphere Radiation – the transfer by waves Convection – the transfer by air movement Conduction- the transfer by the touching of one object to another

Greenhouse Effect The process by which gases trap heat near the Earth’s surface.