15.1 – Earths Atmosphere. What is Atmosphere? A thin layer of air that protects the Earths surface...
-
Upload
hadley-coven -
Category
Documents
-
view
226 -
download
3
Transcript of 15.1 – Earths Atmosphere. What is Atmosphere? A thin layer of air that protects the Earths surface...
Atmosphere15.1 – Earth’s Atmosphere
What is Atmosphere?A thin layer of air that protects the Earth’s
surface from extreme temperatures and harmful Sun rays.
What is the Atmosphere made of?A mixture of gases, solids, and liquids
Earth’s early atmosphere was much different than today.Volcanoes produced nitrogen and carbon dioxide, but
little oxygen.More than 2 billion years ago simple organisms
(cyanobacteria) began producing oxygen.Eventually oxygen formed an ozone layer that
protected Earth from harmful ultraviolet rays from the Sun.
Green plants and diverse life forms developed due to the ozone layer and the protection it gave from the harsh Sun rays.
Atmospheric Make-up ContinuedAtmospheric gases include:
Nitrogen – 78%Oxygen – 21%Carbon Dioxide - .03%Water Vapor – 0-4%Argon – 0.93%
The atmosphere is changing with the introduction of pollutants: increasing human energy use is increasing the amount of Carbon Dioxide.
Pollutants mix with oxygen and other chemicals to form smog.
Atmospheric Make-up ContinuedThe solids that make up the atmosphere
include:DustSaltPollen
The liquids that make up the atmosphere include:Water dropletsDroplets from volcanoes
Layers of the Atmosphere5 main layers of the atmosphere:
Low Layers Troposphere – Lowest layer, where we live. Extends about
10 km up and contains most of the water vapor and gases. Stratosphere – Extends from 10 km to 50 km and contains
the ozone layer.Upper Layers
Mesosphere – Extends from 50-85 km and is where meteors are visible. Ionosphere – Between the meso- and thermosphere. Has
charged particles that can help carry radio waves. Thermosphere – Extends from 85-500 km and is the
thickest layer. Has high temperatures. Exosphere – Outer layers where the space shuttle flies and
has very few molecules.
Atmospheric PressureMolecules closer to
the surface are more densely packed (at higher pressure) than those higher in the atmosphere because of the mass of gases pressing down from higher in the atmosphere.
Temperature in the LayersThe troposphere is warmed primarily by the Earth’s
surface; temperature decreases as altitude increases in this layer.
Temperature increase as altitude increases in the stratosphere, particularly the upper portion because ozone absorbs energy from the Sun.
Temperatures decrease with altitude in the mesosphere.
Thermosphere and exosphere are the first to receive the Sun’s rays, so they are very warm.
A closer look at the Ozone LayerAbout 19-48 km above Earth in the
stratosphere, this layer of 3-atom oxygen molecules (O3) protects the Earth from the Sun’s harmful ultraviolet radiation.Life on Earth depends on it.Pollutants called chlorofluorocarbons (CFCs) are
destroying the ozone layer. CFCs are using in refrigerators, air conditioners,
aerosol sprays, and foam packaging. If these products develop a leak, CFCs can enter the
atmosphere.The ozone layer has a large hole over Antarctica
10.6 million square miles wide.
The End…any questions?