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The Atmosphere
Chapter 6 Notes
Composition of the Atmosphere
• Atmosphere: a mixture
of gasses that surround
the Earth
• Contains the oxygen
you breathe and
protects you from
harmful rays from the
sun.
• Water Vapor: make up
part of the atmosphere .
When conditions
change the water vapor
can change to a liquid
(rain) or solid (snow)
Atmospheric Pressure
• The atmosphere is held around Earth by
gravity.
• Gravity pulls gas molecules toward Earth’s
surface which causes Air Pressure.
• Air Pressure: the measure of the force with
which air molecules push on a surface
Air Pressure
• Air pressure is
strongest on Earth’s
surface.
• As altitude increases
the pressure
decreases.
Atmospheric Temperature
• Differences in the temperature of the
atmosphere result from the amount of
solar energy absorbed.
• Some parts contain more gases which
make them absorb more solar energy
• Other parts contain less gases which
mean they are absorb less solar energy
and are cooler.
Layers of the Atmosphere
Draw
this
picture
The First Layer
• Troposphere
– Lowest layer next to Earth’s surface
– Densest layer
– Contains 90% of the mass of the atmosphere
– The layer we live in
– Gases continuously mix in this layer
– Temperatures vary in this layer
The Second Layer
• Stratosphere
– Gases are layered and do not mix in this layer
– The air is very thin and contains little moisture
– Lower stratosphere is very cold -60 degree
temp. But temperatures rise as altitudes rise
– This layer is the home of the ozone layer, a
protective layer that soaks of ultraviolet rays
from the sun.
stratosphere
troposphere
The Third Layer
• Mesosphere
– The coldest layer
– Temperatures can be as low as -93 degrees
Celsius at the top of the Mesosphere
The Fourth Layer
• Thermosphere
– High temperatures 1000 degrees Celsius or
higher
– It does not feel hot. The particles are moving
very fast but they are not heating up.
Ionosphere
• This occurs between
the mesosphere and
thermosphere.
• Gas particles become
electrically charged
particles called ions
• These ions radiate
energy in the form of
shimmering light
called auroras
Atmospheric Heating
• Energy from the sun
is absorbed by the
atmosphere, land,
and water and is
changed into thermal
energy.
Heat Transfer
Conduction, Convection and
Radiation
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Conduction
Radiation
Heat Transfer
Convection
Examples
Definition
Examples
Definition
Examples
Definition
Thermal Energy Transfer
• Thermal energy transfer is heat moving
from a warmer object to a cooler object.
This is known as thermal energy transfer.
How is Heat Transferred?
There are THREE ways heat can move.
– Conduction
– Convection
– Radiation
CONDUCTION
• Heat is transferred from one particle of
matter to another in an object.
• Conduction = CONTACT/ TOUCH
Have you ever…
• Touched a metal spoon sitting in a pan of boiling
water only to be surprised by HOW hot it is??
Think back to what you know about metals and
nonmetals. What conducts heat better, metal or
nonmetal? Why?
• Think of a metal spoon in a
pot of water being heated.
• The fast-moving particles of
the fire collide with the slowmoving particles of the cool
pot.
• Because of these collisions,
the slower particles move
faster and heat is transferred.
• Then the particles of the pot
collide with the particles in the
water, which collide with the
particles at one end of the
spoon.
• As the particles move faster,
the metal spoon gets hotter.
This process of conduction is
repeated all along the metal
until the entire spoon is hot.
Example of
Conduction
EXAMPLE OF CONDUCTION
• A piece of cheese melts as heat is
transferred from the meat to the cheese
(Contact)
CONVECTION
• Convection is the movement that transfers heat within
fluids and air (gas)
• Heat is transferred by currents within the fluid or gas
• Convection = VENTS (through air and liquid
particles)
• Convection moves in
a circular pattern
Examples of Convection:
• Have you ever noticed that the air near the
ceiling is warmer than the air near the floor? Or
that water in a pool is cooler at the deep end?
• Examples: air movement in a home, pot of
heating water.
• Pick one of these examples and draw the
circular pattern in your notes.
Explaining Convection
• Convection
currents cause
the cooler
breezes you
experience by a
large body of
water.
• These currents
also cause the
movement of
magma within
the earth.
RADIATION
• Radiation is the transfer of energy by
electromagnetic waves
• Radiation does NOT require matter to
transfer thermal energy
• Radiation = Radiates (heat escaping the
sun)
Radiation May Come From Other
Sources
Have you ever sat too close to a campfire
while cooking marshmallows? You’re
enjoying the warmth ….. only to notice that
your skin is really warm?
Examples of RADIATION
1. Fire
2. Heat Lamps
3. Sun
Radiation: Energy Transfer by
Waves
• Radiation is the transfer of energy as
electromagnetic waves.
• The sun radiates huge amounts of energy
But Earth only receives two-billionths of
this energy
• Energy from the sun drives the weather
and makes Earth habitable.
Conduction: Energy Transfer by
Contact
• Thermal Conduction is the transfer of
energy through a material
• Always transferred from warm to cold
areas
• Occurs when air molecules come in direct
contact with the warm surface of the Earth.
Convection: Energy Transfer by
Circulation
• Convection is the transfer of thermal
energy by the circulation or movement of a
liquid or gas
• Most thermal energy is transferred through
convection
Convection
• Example, as air is
heated, it becomes
less dense and rises.
Cool air is denser, so
it sinks. As the cool
air sinks, it pushes
the warm air up. The
cool air is eventually
heated by the Earth's
surface and begins to
rise again. This is
called a convection
current
Greenhouse Effect
• 70% of the radiation
that enters the
atmosphere is
absorbed by the
clouds or by the
Earth’s surface.
• The energy is
converted into
thermal energy.
Greenhouse Effect
• The greenhouse effect is the process by
which the gases in the atmosphere absorb
thermal energy and radiate it back to the
Earth.
• Acts much like the glass walls and roof in
a greenhouse.
Radiation Balance
• In order for the Earth to remain livable, the
amount of radiation coming into the Earth
must equal the amount of thermal energy
the Earth releases into space.
• There must be BALANCE!!
Global Warming
• Global warming is the gradual increase in
average global temperature
• Causes the icecaps to start to melt
• Possible causes
– Too many greenhouse gases
– Human activity
• People are not doing their part to keep the Earth
clean and safe
• Using too many Fossil Fuels!!
Global Winds and Local Winds
• Wind: the movement of air caused by
differences in air pressure
• The greater the pressure, the faster the
wind moves.
• Ex: Hurricanes
Hurricane Andrew
Air Rises at the Equator and Sinks
at the Poles
• Differences in air pressure are caused by
unequal heating of the Earth.
Equator
Poles
•Receives more solar
energy
•Air is warmer and less
dense
•The air rises creating an
area of low pressure
•The warm air flows
towards the poles
•Receives the warm air,
which becomes colder
and denser
•The cold air sinks
creating an area of high
pressure
•The cold air then flows
back towards the
equator.
Pressure belts are found every 30º
• Air travels in many large circular patterns
called convection cells.
• Convection cells are separated by
pressure belts that include bands of high
and low pressure every 30° of latitude
Coriolis Effect
• The Coriolis effect is
the apparent
curving motion of
winds and ocean
currents due to
Earth’s rotation.
• Northern
Hemisphere the
winds traveling
north curve to the
east and winds
traveling to the
south curve to the
west
Global Winds
• The combination of convection cells found
at every 30º of latitude and the Coriolis
effect produces patterns of air circulation
called global winds.
Polar Easterlies
• The wind belts that extend from the poles
to 60° latitude in both hemispheres are
called the polar easterlies.
• They are formed as the cold sinking air
moves from the poles toward 60° north
and 60° south latitude.
• The polar easterlies are responsible for
bringing cold arctic air over the United
States.
Prevailing Westerlies
• The wind belts found between 30° and 60°
latitude in both hemispheres are called the
westerlies.
• The westerlies flow towards the poles from
west to east
• The westerlies are responsible for
bringing moist air to the United States.
Trade Winds
• The winds that blow from 30° latitude
almost to the equator are called trade
winds.
• The Coriolis effect causes the trade
winds to curve west in the Northern
Hemisphere and east in the Southern
Hemisphere
• Early traders used these winds to sail
from Europe to the Americas.
The Doldrums
• The trade winds meet in an area around
the equator called the doldrums.
• There is very little wind because there is
very low pressure.
• This is why it is called the doldrums.
Horse Latitudes
• At about 30° north and 30° south latitude,
sinking air creates an area of high
pressure. The winds are weak in this area
called the horse latitudes.
• Legend says that sailors would get stuck
in this windless area. Instead of wasting
drinking water they would through the
horses overboard.
• Most of the Earth’s deserts are located at
this latitude.
Jet Streams: Atmospheric Conveyor
Belts
• Jet Streams are a
narrow belt of strong
winds that blow in the
upper troposphere.
• Can reach maximum
speeds of 400km/h
• Do not follow regular
patterns
• Important for pilots
and meteorologists.
Local Winds
• Local winds move short distances and can
blow from any direction.
• Shorelines or mountains can create local
wind patterns
• Sea
Breeze- during the day, air over the
ocean is cooler and forms an area of high
pressure. The cool air flows to the land
producing a sea breeze.
• Land Breeze- at night air over the land is
cooler and forms an area of high pressure.
The cooler air moves toward the ocean
producing a land breeze.
Sea and Land Breezes
•Mountain Breeze- at night air along the
mountain slopes cool . This cool air
moves down the slopes into the valley
producing a mountain breeze.
• Valley Breeze – during the day, the sun
warms the air along the mountain slopes.
This warm air rises up the mountain
creating a valley breeze.
Air Pollution
• In December 1952, one of London's
dreaded "pea souper" fogs settled on the
city. But this was no ordinary fog—it was
thick with coal smoke and air pollution. It
burned people's lungs, and the sky grew
so dark that people could not see their
hands in front of their faces. When the fog
lifted four days later, thousands of people
were dead!
Air Pollution
• Air Pollution is the contamination of the
atmosphere by the introduction of pollution
from human and natural sources
• Air pollution is common in many places
• Must be reduced
Primary Pollutants
• Pollutants that are put directly into the air
by humans or natural activity are primary
pollutants
• Ex: dust, sea salt, volcanic gases and ash,
smoke for forest fires, and pollen, carbon
monoxide, dust, smoke, vehicle exhaust
Primary Pollutants
Secondary Pollutants
• Pollutants that form when primary
pollutants react with other primary
pollutants or with naturally occurring
substances are secondary pollutants.
• Ex: ozone and smog
Formation of Smog
• Smog forms when
ozone and vehicle
exhaust react with
sunlight
• Pollution controls
have been put in
effect in some places
to control the amount
of pollution and
reduce the amount of
smog.
Sources of human caused air
pollution
• Transportation is a major cause of air
pollution
• It causes10-20 % of the pollution in the
United States
• Vehicle exhaust contains nitrogen oxide
which contributes to smog
Industrial Air Pollution
• Industrial plants and electrical power
plants burn fossil fuels to produce energy.
• Oil refineries, chemical manufacturing
plants, dry-cleaning businesses, furniture
refinishers, and auto body shops all
produce air pollution.
Indoor Air Pollution
Indoor Air Pollution
• Indoor air pollution can be reduced by
– Ventilation-mixing of indoor air with outdoor
air
– Reduce indoor air pollution by limiting the use
of chemical solvents and cleaners
Acid Precipitation
• Precipitation such as rain, sleet, or snow
that contains acids from air pollution is
called acid precipitation.
• The burning of fossil fuels releases sulfur
dioxide and nitrogen oxide into the
atmosphere.
• They combine with water in the
atmosphere to form sulfuric acid and nitric
acid.
Acid Precipitation and Plants
• Soil naturally has acid.
• Acid precipitation can cause the soil
acidity to increase
• This is called acidification.
• When acidification occurs
– Some nutrients are dissolved
– Aluminum and toxic metals are released and
absorbed by the roots of plants
The Effects of Acid Precipitation on
Forests
• Eastern Europe
:Poland
• Forests have been
severely damaged by
acid precipitation
Acid Precipitation and Aquatic
Ecosystems
• If the amount of acid
increases in the water
then the plants, fish, and
other organisms may die.
• A rapid change in a body
of water’s acidity is
called acid shock.
• Some communities use
powered lime a base to
reduce the amount of
acid in the water.
The Ozone Hole
• 1985 scientists reported that the ozone
layer over Antarctic regions was thinning.
• Chemicals called CFC were causing the
ozone to break down into oxygen
The Ozone Hole
•1987 action was taken to
solve the ozone problem
•A ban of all CFC
chemicals was created
•CFC alternatives were
developed
•CFC chemicals take 60
to 120 years to quit
working. Therefore even
with the ban CFC’s used
30 years ago are still
harming the ozone now!!!
Air Pollution and Human Health
Short Term Effects
Long Term Effects
•Headache
•Nausea
•Irritation to eyes, nose,
and throat
•Coughing
•Upper respiratory
infection
•Worsening of asthma
and emphysema
•Emphysema
•Lung cancer
•Permanent lung
damage
•Heart disease
Cleaning up air pollution
• 1970 the United States Clean Air Act was
passed by Congress.
• This act gives the Environmental
Protection Agency the authority to control
the amount of pollutants that can be
released from any source.
• The EPA checks air quality.
• The Clean Air Act was strengthened in
1990.
Air Pollution from Industry
• The Clean Air Act
requires factories to
use scrubbers.
• A scrubber is a device
that is used to remove
some pollutants
before they are
released by
smokestacks.
The Allowance Trading System
• The Allowance Trading System – the EPA
gives allowances for the amount of
pollutants that companies can release.
• If a company goes over--- they pay fines.
• If a company is under they can sell there
extra allowances to other businesses.
Reducing Air Pollution from
Vehicles
• The EPA requires car
makers to meet
certain criteria for
exhaust.
• Use of cleaner fuels
and more efficient
engines
• Hybrids, carpools,
public transportation,
or biking and walking
all reduce air
pollution.