Download Atmosphere

Atmosphere
Chapter 6
Earth’s Atmosphere
Importance of the Atmosphere
• Atmosphere: thin
layer of air that forms
a protective covering
around the planet
• Balances heat
absorbed (from sun)
and heat released
(into space)
• Protects us from
sun’s harmful rays
What is the atmosphere made up
of?
• Mixture of gases, liquids and
solids
• Extends from earth’s surface to
outer space
• Gases in the atmosphere
– 78% : Nitrogen
– 21% : Oxygen
– 1% : other gases
• 0.93%: Argon
• 0.03%: Carbon Dioxide
• Vapor, ozone, helium, methane,
krypton,
xenon
Atmosphere continued
• Solids in the atmosphere:
– dust, salt, pollen
• Liquids in the atmosphere
- Small liquid droplets from clouds, volcanic
eruptions
- Mount Pinatubo---
Phillipines
Layers of the atmosphere
Layers of the Atmosphere
• 5 layers, each with own
unique properties
• Lower layers
– Troposphere
– Stratosphere
• Upper layers
– Mesosphere,
– Thermosphere
– Exosphere
Troposphere
• Lowest layer
• Extends up to 10 km
• Temperature decreases as you go up
• Where all weather occurs
• Most of total mass of atmosphere is
located here (ocean, mountains, people, animals,
plants etc)
Stratosphere
• Layer above troposphere
• 10-50km
• Temperature increases as you go up
• Contains Ozone (O3)
– Ozone (O3) : gas that absorbs sun’s
harmful rays (solar radiation)
Mesosphere
• Layer above stratosphere
• 50-85km
• Temperature decreases as you go up
• Find meteors here
• Most meteors that enter the atmosphere
burn up here
Thermosphere
• Layer above the mesosphere
• 85km-500km
• Temperature increases as you go up (heated by
radiation from the sun)
• Thickest layer, known for its high temperatures
• Air is very thin (molecules very spread apart)
• Contains layer-ionosphere (radio waves) and
exosphere
Exosphere
• Highest layer of the atmosphere (before
space)
• 500 km-1,000km, upper boundary 10,000
km (6,200 miles)
• Very thin air (molecules extremely far apart)
• Satellites
• Space shuttle orbits
Glossary Words
• Atmosphere
• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• Exosphere
• Ionosphere
• Water cycle
Energy Transfer in the
Atmosphere
Light energy VS Heat Energy
Energy from the Sun
• Sun provides most energy on
Earth
• Drives ocean and wind
currents
• Allows plants to grow and
produce food provides
nutrition to animals
• Sun’s energy can be…
• - reflected back into space by
clouds, atmosphere and
Earth’s surface (35%)
• - Absorbed by the atmosphere
or Earth’s surface (65%)
Heat
• Heat- flow from high temperature to low temperature
• 1) Energy from the sun reaches Earth’s surface
• 2) Heat transferred by radiation, conduction,
convection (distributes the Sun’s heat throughout the
atmosphere)
Radiation
• Energy transferred in
the form of rays or
waves
• Sun reaches Earth in
the form of radiant
energy
• Feel the Sun’s heat
and warmth
Conduction
• Transfer of energy that
occurs when molecules bump
into one another (direct
contact)
• Earth’s surface conducts
energy directly to the
atmosphere
- As air moves over warm
land or water, molecules in
air are heated by conduction
Convection
• Transfer of heat by the flow
of material
• Circulates heat throughout
the atmosphere
• Cool air sinks, Warm air
rises Convection current
The Water Cycle
• Hydrosphere: describes all water on Earth
• Constant cycling of water within the atmosphere and
hydrosphere- determines weather patterns and
climate types
• Water moves from
– Earth Atmosphere Earth
• Evaporation Condensation Precipitation
The Water Cycle
• 1) Sun- liquid (lakes,
streams, oceans) gas
(EVAPORATION)
• 2) Water vapor cools
changes back to a liquidclouds form
(CONDENSATION)
• 3) Clouds grow in
droplet size and fall to
Earth (PRECIPITATION)
• 4) RUNOFF precipitation
to groundwater back
to ocean
Questions from Water Cycle Model
and Study Cards
• What do you see happening?
• What did the ice do to the water that went into
the air?
• What happened to the water in the air after it
cooled?
• Where did the drops of water (rain) go?
• How was the water in our model heated?
• What heats water in the real oceans and lakes?
• What did our lamp represent?
Atmospheric Pressure
• Pressure= Force/Area (force exerted on a
surface divided by the total area over which the force is
exerted)
• Atmospheric Pressure
– Air (makes up the atmosphere around Earth)
around you presses on you with tremendous
force
Variations in Atmospheric Pressure
• Atmospheric pressure
changes with altitude
• As altitude increases-
pressure decreases
– Fewer air particles are found
in a given volume
• As altitude decreases 
pressure increases
– More air particles are found
in a given volume
Balanced Pressure
• Why don’t we feel air pressure?
• Pressure exerted outward by fluids of your
body balances the pressure exerted by the
atmosphere on the surface of your body
Fluids in her body
exert a pressure
that BALANCES
atmospheric
pressure
Pascal
• Experiment with a balloon (pg 120)
– Designed an experiment in which he filled a
balloon only partially with air. He then had the
balloon carried to the top of a mountain. As he
predicted, the balloon expanded while being
carried up the mountain.
– The amount of air inside the balloon stayed the
same, while the air pressure pushing in on it
from the outside decreased. The particles of
air inside the balloon were able to spread out
further
Air movement
• Uneven heating of Earth’s surface causes some
areas to be warmer than others.
• Due to Earth’s curve
– Equator receives more radiation (direct) than North or
South poles
Heated Air
• Convection currents
– Equator: hotter air from suns radiation—less
dense (rise)---LOW PRESSURE
– Poles: colder air---more dense (sink)---HIGH
PRESSURE
The Coriolis Effect
• Rotation of the Earth causes
moving air and water to
appear to turn to the
– RIGHT north of the equator
(northern hemisphere)
– LEFT south of the equator
(southern hemisphere)
Coriolis Effect + uneven heating of
Earths surface  Distinct wind
patterns which influence
weather
Global Winds
• Doldrums :
– near the equator (low pressure area)
– Windless, rainy zone
• Trade Winds:
– air extending to 30°N & S
– steady winds
• Westerlies:
– 30 °– 60° N&S moves opposite
trade wind,
– responsible for much movement of
weather in N. Hemisphere
• Easterlies:
– Found near the poles
– north pole-move southwest,
– south pole- northwest
Jet Streams
• Narrow belts of strong
winds that blow near the
top of the troposphere
(~8mi high)
• The polar jet stream
forms at the boundary of
cold, dry polar air to the
north and warmer, more
moist air to the south.
Local Wind Systems
• Smaller wind systems affect local weather
• Sea and Land Breezes
– Convection currents over areas where land meets the
seawinds
SEA BREEZE
LAND BREEZE
During the day (solar radiation
warms the land more than water)
During the night, (land cools more
rapidly than water)
Warm air rises over land, Cool air
sinks and moves from water
towards land
Warm air rises over water, cool air
sinks and moves from land toward
the water
Sea Breeze (Day)
Land Breeze (Night)
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