Atmosphere

• The envelope of gases that surrounds the Earth

• Composed of:– Nitrogen (78%)– Oxygen (21%)– Carbon Dioxide (0.04%)– Water Vapor (0.5%)– Other Gases

Layers of the Atmosphere

• The Earth’s atmosphere is divided into five basic layers:– Troposphere– Stratosphere– Mesosphere– Thermosphere– Exosphere

Air Pressure/Air Particles

• Most of the air particles in the atmosphere can be found in the troposphere

• Troposphere has high air pressure

• Thermosphere has few air particles and very low air pressure

Temperature Changes

• If Earth’s atmosphere is invisible, how can we divide it into different layers?

• We divide the atmosphere into different layers based upon changes in temperature

Troposphere

• Layer closest to the Earth

• Contains most of the air particles because gravity pulls them down

• Only layer that has weather

• Layer in which we live

Stratosphere

• 10-50 Km above the Earth

• Contains the “Ozone Layer”- protects us from the sun’s UV rays

• Airplanes prefer to fly here

• Temperature rises slowly as you go higher

Mesopshere

• 50-85 Km• Temperatures drop

greatly in this layer• Coldest temperatures in

the atmosphere• Contains a layer of

charged particles called the “ionosphere”- This allows radio/tv signals to work

Thermosphere

• Over 85-300 Km above the Earth

• Thinnest layer- particles very spread out

• Temperatures rise as you go higher- hottest layer

• Where the Northern Lights occur

Aurora Borealis (Northern Lights)

Exosphere

• Over 300 Km above Earth

• Beginning of outer space

• Where satellites fly