Transcript Chapter 15 Notes Section 1

Chapter 15
The
Atmosphere
Mr. Manskopf
Notes Also At
http://www.manskopf.com
Why Care About The Air?
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 Earth’s
atmosphere.
Take a deep breath
What is air made out of?
Is air strong? Is it matter?
Why is our atmosphere important?
Why doesn’t it float away
Chapter 15 Big Idea
Our atmosphere is critical to
all life on Earth. Human
actions have a great
impact on our atmosphere.
Section: Earth’s Atmosphere
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Describe the properties of the atmosphere.
Identify the main layers of the atmosphere.
Explain how heat is transferred in the
atmosphere
What is the Atmosphere?
Thin layer of gases
surrounding our
planet
 Skin of apple thin
 We live at bottom
 Air is a fluid
 Why don’t gases fly
away into space?
Why is it important?
Earth’s atmosphere makes life on
Earth possible.
 Protects us from sun’s rays.
 Provides vital gases like
oxygen, nitrogen and carbon
dioxide.
 Keeps temperature comfortable
 Allows water to circulate
around planet.
 Protects us from meteoroids.
The Air Around You
Weather
Weather is the
state of the
atmosphere
at any one
moment.
What is it made of?
Earth’s Atmosphere is
made of:
 78 % Nitrogen
 21% Oxygen
 1% a bunch of others
(Argon, Carbon
Dioxide, Water
Vapor…)
Carbon Dioxide vs Carbon Monoxide?
Water in the Air
Relative Humidity
 Amount of water
vapor in the air
 Changes constantly
 Warm Air = More
Moisture
 Condensation =
Clouds
Cloud Formation
http://youtu.be/NiCSk1zxMEs
Air temperature
Changes vertically and
horizontally on Earth
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Why is it cold on top
of mountains?
Why are the tropics
warmer than the
polar regions?
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?
As altitude increases air pressure
decreases…quickly
Barometers
An instrument
used to
measure air
pressure.
Changing air pressure is a great indicator
of weather changes.
Air pressure
Differences in air
pressure is going
to help us
understand:
 Wind
 Cloud formation
 Tornadoes
 Almost all weather
Four Main Layers of Atmosphere
The four main layers
of our atmosphere
are classified
according to
changes in
temperature.
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Troposphere
Stratosphere
Mesosphere
Thermosphere
The Troposphere
The Troposphere:
 Inner most layer
(0 to 12km)
 Where all weather
occurs
 The temperature
decreases to -60
degrees at top.
The Troposphere
Clouds, rain, snow
and all
precipitation
occur here.
Air Pressure and
Temperature
drop quickly in
troposphere.
Stratosphere
Layer above
troposphere where
atmosphere warms
slightly
Ozone layer located
there blocks out
harmful UV Rays
Mesosphere
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“Middle Layer”
Temperatures reach 90 degrees Celsius
Where meteoroids
burn up in
atmosphere
Thermosphere
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“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
Heat Transfer in the
Troposphere
1) Radiation: The
transfer of energy
through space,
such as heat from
the sun to Earth’s
atmosphere
2) Conduction:
The transfer of
heat directly
between two
objects that are
in contact
3) Convection:
The transfer of
heat by the
movement of
currents within a
fluid (liquid or
gas)
Air Masses And
Fronts
The Air Outside Today, Was
Somewhere Else Yesterday
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.
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.
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
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Where do each of these air
masses originate?
Temperature dropped 20 degrees
between 6AM and 11AM. WHY?
Part 2 Air Masses and Fronts
What type of air mass yesterday vs. today?
What Are Fronts?
Fronts are areas
where 2 or more
air masses
collide.
Air with different
temperature,
humidity and
pressure DO NOT
MIX WELL.
Types of Fronts
There are four
types of front:
1) Cold Front
2) Warm Front
3) Stationary
Front
4) Occluded
Front
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.
Cold Fronts
Cold Fronts:
 Often move quickly
 Can bring abrupt
changes to weather
(summer storms)
 Behind front is
often cool and clear
weather
Cold Fronts
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.
Warm Fronts
Warm Fronts
move more
slowly than cold
fronts so
weather changes
occur more
slowly.
In winter they often
bring snow.
Warm Fronts