Chapter 15 The Atmosphere

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Chapter 15The Atmosphere

• Mr. Manskopf
• Notes Also At http//www.manskopf.com

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Why Care About The Air?
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You breathe out of which layer?
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• The air we breathe and all the weather we see is
  contained in the lowest 1 of the Earths
  atmosphere.

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Take a deep breath
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What is air made out of?
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Is air strong? Is it matter?
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Why is our atmosphere important? Why doesnt it
float away
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Chapter 15 Big Idea

• Our atmosphere is critical to all life on Earth.
  Human actions have a great impact on our
  atmosphere.

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Section Earths Atmosphere

• Describe the properties of the atmosphere.
• Identify the main layers of the atmosphere.
• Explain how heat is transferred in the atmosphere

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What is the Atmosphere?

• Thin layer of gases surrounding our planet
• Skin of apple thin
• We live at bottom
• Air is a fluid
• Why dont gases fly away into space?

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Why is it important?

• Earths atmosphere makes life on Earth possible.
• Protects us from suns rays.
• Provides vital gases like oxygen, nitrogen and
  carbon dioxide.
• Keeps temperature comfortable
• Allows water to circulate around planet.
• Protects us from meteoroids.

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The Air Around YouWeather

• Weather is the state of the atmosphere at any one
  moment.

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What is it made of?

• Earths Atmosphere is made of
• 78 Nitrogen
• 21 Oxygen
• 1 a bunch of others (Argon, Carbon Dioxide,
  Water Vapor)

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Carbon Dioxide vs Carbon Monoxide?
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Water in the Air

• Relative Humidity
• Amount of water vapor in the air
• Changes constantly
• Warm Air More Moisture
• Condensation Clouds

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Cloud Formation

• http//youtu.be/NiCSk1zxMEs

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Air temperature

• Changes vertically and horizontally on Earth
• Why is it cold on top of mountains?
• Why are the tropics warmer than the polar regions?

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Air Pressure

• The force of a column of air pushing down on an
  area
• Where is air pressure greater, sea level or top
  of a mountain?
• Why are airplanes pressurized?

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As altitude increases air pressure
decreasesquickly
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Barometers

• An instrument used to measure air pressure.

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Changing air pressure is a great indicator of
weather changes.
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Air pressure

• Differences in air pressure is going to help us
  understand
• Wind
• Cloud formation
• Tornadoes
• Almost all weather

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Four Main Layers of Atmosphere

• The four main layers of our atmosphere are
  classified according to changes in temperature.
• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

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The Troposphere

• The Troposphere
• Inner most layer
• (0 to 12km)
• Where all weather occurs
• The temperature decreases to -60 degrees at top.

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The Troposphere

• Clouds, rain, snow and all precipitation occur
  here.
• Air Pressure and Temperature drop quickly in
  troposphere.

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Stratosphere

• Layer above troposphere where atmosphere warms
  slightly
• Ozone layer located there blocks out harmful UV
  Rays

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Mesosphere

• Middle Layer
• Temperatures reach -90 degrees Celsius
• Where meteoroids burn up in atmosphere

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Thermosphere

• Thermo means heat
• Air is only 0.0001 as dense as sea level
• Air slowly blends into outer space
• Hottest layer of atmosphere because energy from
  the sun strikes it first

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Heat Transfer in the Troposphere
1) Radiation The transfer of energy through
space, such as heat from the sun to Earths
atmosphere
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2) Conduction The transfer of heat directly
between two objects that are in contact
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3) Convection The transfer of heat by the
movement of currents within a fluid (liquid or
gas)
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Air Masses And Fronts The Air Outside Today, Was
Somewhere Else Yesterday
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What IS An Air Mass?

• An Air Mass is a huge body of air with similar
  temperature, humidity and pressure.
• They sometimes spread over hundreds of square
  miles.

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Types of Air Masses

• There are 4 main types of air masses
• 1) Polar
• 2) Tropical
• 3) Maritime
• 4) Continental
• Each has unique weather associated with it.

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4 Major Air Masses of North America

• Maritime Tropical Warm, Moist Air
• Maritime Polar Cold, Moist Air
• Continental Tropical Warm, Dry Air
• Continental Polar Cold, Dry Air
• Where do each of these air masses originate?

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Temperature dropped 20 degrees between 6AM and
11AM. WHY?
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Part 2 Air Masses and Fronts
What type of air mass yesterday vs. today?
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What Are Fronts?

• Fronts are areas where 2 or more air masses
  collide.
• Air with different temperature, humidity and
  pressure DO NOT MIX WELL.

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Types of Fronts

• There are four types of front
• 1) Cold Front
• 2) Warm Front
• 3) Stationary Front
• 4) Occluded Front

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Cold Fronts

• Cold Fronts occur where cold air runs into slowly
  moving warm air.
• Cold air being more dense pushes warm air up.
  Warm moist rising air can cause clouds and storms.

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Cold Fronts

• Cold Fronts
• Often move quickly
• Can bring abrupt changes to weather (summer
  storms)
• Behind front is often cool and clear weather

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Cold Fronts
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Warm Fronts

• Warm Fronts occur where a warm air mass collides
  with a slower moving cold air mass.
• Because warm air is less dense, it rides above
  the cold air.

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Warm Fronts

• Warm Fronts move more slowly than cold fronts so
  weather changes occur more slowly.
• In winter they often bring snow.

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Warm Fronts
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