1. Atmosphere layers 15.1

2. Thermosphere Extends from 80km out Air is thinnest in this layer and much less dense Temp rises the higher you go (molecules moving fast) Has 2 layers: – Ionosphere – 80-400km-Contains charged particles that reflect radio waves back to Earth and cause light displays like Aurora Borealis at high latitudes – Exosphere – outer portion and extends from 400+km getting thinner as it extends out to vacuum of space

3. Mesosphere Extends from 50-80 km above Earth (third layer going up) Protects Earth’s surface from being hit by most meteoroids (they burn up in this layer) Air is less dense than in the stratosphere As you go up in the mesosphere the temperature decreases Coldest layer

4. Stratosphere Extends from 12-50 km above the Earth (2 nd layer) Contains ozone (O₃) layer which filters out harmful ultraviolet rays from Sun Ozone absorbs energy and converts it to heat As you get higher in the ozone layer the temperature rises In Stratosphere air is less dense than in the Troposphere

5. Troposphere The layer of the atmosphere in which clouds and weather occur. Thinnest layer but contains most of the mass because gas molecules are denser (closer together) than in other layers. 0-12 km above Earth’s surface – Lowest layer Temperature goes down the higher you get in the troposphere