Layers of the Atmosphere

1. Layers of the Atmosphere Notes

2. The layers are separated and distinguished by changes/differences in temperature! Key Point!

3. Scientists divide Earth’s atmosphere into 4 main layers according to changes in temperature .

4. Lowest layer:Troposphere • “Tropo” means turning or changing • Earth’s weather occurs here • Depth of troposphere is 16km above Earth’s surface • As altitude increases, the temperature decreases. • At top of layer, temperature stops decreasing and stays at -60 degrees C. • Water here forms thin, feathery clouds of ice.

5. 2nd Layer: Stratosphere • Extends from top of troposphere to about 50km above Earth’s surface. • Strato- means “layer” or “spread out” • Contains the ozone layer • Atmosphere is drier

6. Stratosphere cont’ • Lower part is cold (-60*C) but upper part is warmer • Warmth occurs because the middle part of stratosphere contains a layer of air where there is much more ozone than the rest of atmosphere. • Ozone absorbs and scatters UV radiation from sun protecting Earth.

7. 3rd Layer: Mesosphere • Meso- means “middle” • Begins at 50km above Earth and extends to an altitude of 80km. • Coldest layer; temps drop the higher in altitude you go (-90*C) • Radio waves are reflected to Earth • Meteors burn up in this layer

8. 4th Layer: Thermosphere • Thermo- means “heat” • Extends 80km to infinity above Earth’s surface • Temps increase with altitude • Hottest layer up to 1,800*C

9. Thermosphere cont’ • The thermosphere is divided into 2 layers • Lower layer-IONSPHERE begins at 80km to 400km above Earth’s surface • Northern Lights or Aurora Lights occur in this layer • Outer layer-Exosphere begins at 400km to no definite outer limit • Satellites orbit Earth in this layer

11. Atmosphere Video Clip ~5 min