Atmosphere

“This PowerPoint puts the “phere” in other, lesser PowerPoints” - PPTA

Composition of Air

• There are many different types of gasses in the atmosphere

• They include nitrogen, oxygen, argon, carbon dioxide and other noble gasses

• Nitrogen and oxygen make up 99%

Layers of the atmosphere• There are 5 layers in the atmosphere• They are the troposphere, stratosphere, mesosphere,

thermosphere, and exosphere.

Troposphere

• This is the layer that is closest to the surface of the earth

• It’s elevation ranges from 0 to about 17 km

• Contains most of the mass of the atmosphere

• Temperature decreases with elevation

Stratosphere

• This layer sits on top of the troposphere

• It’s elevation ranges from 10 km to around 50 km

• This layer contains the ozone layer, which protects us from harmful UV radiation

• Ozone (O3) is also a gas emitted by cars and factories• Ozone in stratosphere = good Ozone in troposphere =

bad

Mesosphere

• This layer is above the stratosphere

• It’s elevation ranges from 50 to 85 km

• Temperature decreases with altitude because there is very little air

• This is where most small meteorites burn up

Thermosphere

• This is the 2nd highest layer of the atmosphere

• It’s height ranges from 85 to 600 km

• High energy radiation is absorbed causing the northern lights (aurora borealis) and an increase in temperature

Exosphere

• Outermost layer of Earth’s Atmosphere

• Transition from atmosphere to outer space

• Often considered outer space

Absorption and Reflection• Thanks to the Atmosphere, the amount of energy from

the Sun that actually hits warms Earth is cut in half.

Greenhouse Effect1. Most of the visible light radiation from the Sun is invisible to gases in the atmosphere, hitting and warming the Earth.

2. The Earth then emits a low energy infrared radiation which the gases in the atmosphere are very efficient at absorbing and reflecting.

Energy Transfer in the Atmosphere• Radiation – the transfer of

thermal energy by electromagnetic waves.

• Conduction – transfer of thermal energy between touching objects.

• Convection – transfer of thermal energy by the movement of heated material from one place to another due to density differences.