Earth’s Atmosphere

Chapter 1: Section 1

Importance of the Atmosphere

• Earth’s atmosphere is a thin layer of air that forms a protective covering around the planet.

• If Earth had no atmosphere, then days would be extremely hot and nights would be extremely cold.

Importance of the Atmosphere

• Earth’s atmosphere maintains a balance between the amount of heat absorbed from the Sun and the amount of heat that escapes back into space.

Atmosphere

Heat absorbed from Sun

Heat escaped from Earth

Importance of the Atmosphere

• Earth’s atmosphere also protects us from the Sun’s harmful rays.

Makeup of the Atmosphere

• Earth’s atmosphere is a mixture of gases, solids, and liquids that surrounds the planet.

• It extends from Earth’s surface into outer space.• Gases – Nitrogen (78%), Oxygen (21%), Other

Gases (1%)• Solids – Dust (wind picks up from ground), Salt

(ocean spray), Pollen (plants)• Liquid Droplets (water and volcanic materials)

Layers of the Atmosphere

• There are five layers of the atmosphere.• The lower layers include the troposphere and

stratosphere.• The upper atmospheric layers include the

mesosphere, thermosphere, and exosphere.

The Lower Layers - Troposphere

• We live within the troposphere. It is the lowest layer of the atmosphere.

• It contains 99% of the water vapor and 75% of the atmospheric gases.

• Rain, snow, and clouds occur in the troposphere.

The Lower Layers - Stratosphere

• The stratosphere extends from about 10km above the Earth’s surface to 50 km.

• Contains the ozone layer, which protects us from the Sun’s harmful rays.

The Upper Layers - Mesosphere

• Extends from the top of the stratosphere to 85km above Earth.

• Shooting stars are meteors in the mesosphere.• The frigid temperatures in the upper

mesosphere create noctilucent clouds – clouds of ice crystals.

The Upper Layers - Thermosphere

• Named for its high temperatures.• It’s the thickest atmospheric layer and is found

between 85km and 500km above Earth’s surface.

• Auroras occur in the thermosphere.

The Upper Layers - Ionosphere

• Within the mesosphere and thermosphere is a layer of electronically charged particles called the ionosphere.

• It allows radio waves to travel across the country to another city.

The Upper Layers - Exosphere

• The outer most layer of the atmosphere.• Space shuttles and satellites orbit the Earth in

the exosphere.

Gravity

Temperature in Atmospheric Layers

The Ozone Layer

Ozone Destruction