1. Layers of the Atmosphere Chapter 12.3 Gee we’ve come a long way!!

2. Scientists divide Earth’s atmosphere into four main layers that are classified according to changes in the temperature. – Troposphere – Stratosphere – Mesosphere – thermosphere

3. Troposphere This is the inner, or lowest of Earth’s atmosphere. The troposphere is the layer in which Earth’s weather occurs. As altitude in the troposphere increases (you go higher), the temperature decreases (it gets colder…just like climbing a mountain!).

4. Stratosphere The stratosphere extends from the top of the troposphere to about 50K above Earth’s surface. The stratosphere is the second layer of the atmosphere and contains the ozone layer. The ozone layer provides us protection from the dangerous ultraviolet rays from the sun’s radiation.

5. Mesosphere The mesosphere is the third layer of the atmosphere. Temperatures here start to reach -90 C….very, very cold! The mesosphere is the layer that protects Earth’s surface from being hit by most meteriods.

6. Thermosphere Near the top of the atmosphere the air is very thin. The outer most layer of the atmosphere is Earth’s thermosphere. The thermosphere has no limit, but blends with outer space. Although at the top of the atmosphere, the thermosphere is very hot.