Transcript Earth’s atmosphere

Earth’s atmosphere
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Layers of gases that surround the
planet
Makes conditions suitable for living
things
Jobs of our Atmosphere:
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Contains oxygen for breathing
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Traps energy from the Sun
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Protects us from harmful radiation from
the Sun
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Allows water to exist as a liquid
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Prevents most meteoroids from hitting
Earth
What is Earth’s
atmosphere made up of?
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Nitrogen
Oxygen
Carbon Dioxide
Water Vapor
Other gases
Nitrogen
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Most abundant gas
Necessary to repair body cells
Most living things must obtain nitrogen
by eating plants
Oxygen
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2nd most abundant gas
It’s used in everything from breathing
to burning
Ozone is a form
of oxygen
Carbon Dioxide
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Small amount exists in the atmosphere
Plants need it to produce food
Animals & the burning
of fuels release Co2
into the atmosphere
Water Vapor
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Water in the form of gas
It’s invisible
Amount in the atmosphere may depend
on the placeDesert: very little; Rain forest: tons
Plays an important role in weather
Other Gases
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Argon & other gases make up 1% of
the atmosphere
Air Pressure
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The result of the weight of a column
of air pressuring down on an area
How do you measure air
pressure?
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A barometer is used to measure the
change in air pressure
Falling air pressure-bad weather is
coming
Rising air pressure-weather is clearing
Air Pressure & Density
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Air pressure and density decrease as
altitude increases
Sea-Level: air pressure is greatest
Mountain Top: air pressure is lessened
What are the different
layers of our atmosphere?
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4 main layers classified according to
temperature
– troposphere
– stratosphere
– mesosphere
– thermosphere
Troposphere
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Inner or lowest layer
Shallowest layer
Where “we” live
Where weather occurs
Most mass found here
Stratosphere
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Where the “Ozone Layer” is located
Absorbs UV rays
Where planes fly
Mesosphere
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Middle layer
Where most meteoroids burn up
Serves as a protective layer for
meteoroids
Thermosphere
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Outermost layer
Extremely hot
Absorbs energy from the Sun &
converts it into heat
Has 2 sub-layers
– ionosphere
– exosphere
Ionosphere
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Lowest layer in the thermosphere
Aurora Borealis occurs here
Exosphere
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Outermost layer in the thermosphere
Where satellites travel
Energy in Earth’s
Atmosphere
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Energy travels to earth from the sun in
the form of waves
Electromagnetic waves (EM waves)
Electromagnetic Waves
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Form of energy that can move through
the vacuum of space
Radiation is the direct transfer of EM
waves
Energy from the sun…
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Most is in the form of visible light &
infrared radiation
Small amounts of UV radiation
Energy from the Sun
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50% is absorbed by land & water
20% is absorbed by gases
25% is reflected by gases or clouds
5% is reflected back into the
atmosphere
*The energy is either reflected,
absorbed or scattered
Heat Transfer
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Thermal energy: total energy of
motion in the particles of a substance
Temperature: average amount of
energy of motion of each particle in a
substance
Heat: transfer of thermal energy from
a hotter object to a cooler one
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Temperature is 1 of the most
important factors that affects our
weather!
Temperature is measured with a
thermometer!
Heat Transfer
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3 ways heat is transferred within our
atmosphere
– Radiation
– Conduction
– Convection
Radiation
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Direct transfer of heat through EM
waves
Ex: heat from the sun
Conduction
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Heat transferred through 2 objects
touching
Ex: Pan heating on the stove top
Convection
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Heat transferred through the fluid
movement of a gas/liquid
Ex: Heating vents in your house
Which heat transfer is mostly
responsible for heating Earth’s
atmosphere?
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Convection!
The troposphere is heated through
convection currents.
Air near the land or water is heated,
hot air rises, cools, falls towards
Earth’s surface, process begins again.
Wind
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Horizontal movement of air from an
area of high pressure to an area of low
pressure
Winds are caused by differences in air
pressure
Measuring Wind
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Wind speed is measured with an
anemometer
Local Winds
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Local winds-winds that blow over short
distances
– Sea breeze (sea – land)
– Land breeze (land-sea)
Global Winds
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Global Winds-winds that blow steadily
from specific directions over long
distances
Coriolis Effect
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Earth’s rotation makes winds curve
N.H.-winds curve to the right
S.H.-winds curve to the left
Global wind belts & calm
areas
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Doldrums
Horse Latitudes
Trade Winds
Prevailing Westerlies
Wind belts
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Trade winds-Winds that blow
towards the equator from 30°S/N
latitude
Prevailing Westerlies-winds that
blow towards the poles from 30°S/N
latitude
*Prevailing Westerlies play an important
role in the US weather
Calm areas
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Doldrums-areas near the equator
with little to no wind
Horse Latitudes-30°N/S Latitude,
the air stops moving toward that poles
& sinks
Jet Stream
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Bands of high winds 10km above
Earth’s surface
Usually blow from west to east
Speeds of 200-400km per hr