7-3: Layers of the Atmosphere

6th Grade Earth Science

7-3: Layers of the Atmosphere

7-3: Layers of the Atmosphere

• The Earth’s atmosphere has 4 main layers:

1. Troposphere

2. Stratosphere

3. Mesosphere

4. Thermosphere

Layers of the Atmosphere

7-3: Layers of the Atmosphere

• The troposphere is the lowest layer: 9 km to 16 km thick.

• Most of Earth’s weather occurs in this layer.

• Also, most of the Earth’s mass is found here.

1st - Troposphere

7-3: Layers of the Atmosphere

• The stratosphere is the 2nd layer, just above the troposphere – the top is about 50 km above the Earth.

• It contains the Ozone Layer – which blocks harmful radiation.

2nd - Stratosphere

7-3: Layers of the Atmosphere

• It is about -60˚C at the bottom, and actually warms toward the middle due to the ozone layer.

7-3: Layers of the Atmosphere

• The mesosphere is the 3rd layer, just above the stratosphere – the top is about 80 km above the Earth.

• It is where most meteoroids burn up as shooting stars.

• Very cold, about -90˚C

3rd - Mesosphere

7-3: Layers of the Atmosphere

• The thermosphere is the 4th layer, just above the mesosphere – its top blends into space.

• It is very hot, 1600˚C, because the sun’s radiation hits this layer first – heating up the Oxygen and Nitrogen.

4th - Thermosphere

7-3: Layers of the Atmosphere

• Just above the ionosphere, at about 400 km, is the exosphere, which has no top!!! It just slowly blends into space over 1000’s of kilometers.

7-3: Layers of the Atmosphere

7-3: Layers of the Atmosphere

7-3: Layers of the Atmosphere

7-3: Layers of the Atmosphere

7-3: Layers of the Atmosphere

Clouds hitting the stratosphere.

7-3: Layers of the Atmosphere

Review

7-3: Layers of the Atmosphere Summary

• The Earth’s atmosphere has 4 main layers; troposphere, stratosphere, mesosphere, and thermosphere.

• The thermosphere has two parts, lower part is the ionosphere and the upper part is the exosphere.