Transcript Chapter 16 - OG

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What is weather?
State of the atmosphere at a specific time and place.
Describes conditions such as: air pressure, wind, temp. and
amount of moisture in the air (variables of weather)
SUN’S HEAT
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Sun provides almost all
of Earth’s energy.
EARTH’S AIR & WATER
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Sun causes evaporation
Which forms clouds
Which falls to Earth as
rain or snow.
Repeat :-)
AIR MOLECULES
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Always moving
Randomly – even when
there is no wind.
TEMPERATURE
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Def.: measure of the
average amount of
motion of molecules
(kinetic energy)
Temp – high –
molecules move fast –
feels warm
Temp – low- move less
fast – feels cool
DEFINITION
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Air moving in a specific
direction
Measured w/
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Weather vanes
Weather socks
Anemometer
 “a nuh MAH muh tur”
AIR
Warm – low atmospheric
pressure
Cool – high atmospheric
pressure (denser - sinks)
*****Air moves from
regions of high to low
pressure (cool to warm)
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Def: the force a column of air applies on
the air or a surface below it.
Instrument used to measure air pressure
= BAROMETER
Label = millibars (mb)
Def. : amount of water vapor present in the air
 Warmer temps – move too quickly
to come together
 Cooler temps – move slower so
water vapor molecules stick together
(condense!!!)
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Condensation = air is saturated
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DEF: measure of the amount of water vapor
present in the air COMPARED to the
maximum amount of water vapor the air could
contain at that temperature.
.
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Definition:
TEMPERATURE at which air is
saturated
and condenses
*** changes w/ the amount of water vapor
in air.
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MiniLab
Use Fig 3 ~ GRAPH
Reading the graph
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How much water vapor is in the air at 15 degrees C?
What temperature has 5 g/m 3 water vapor?
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Stratus
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Cumulus
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Flat white and layered.
Form at low altitudes (up to 2000 m)
Associated w/ fair weather or rain, snow
Puffy, white w/ flat bases ~ piled up.
Sometimes tower to great heights (2000 to 6000 m)
Cirrus
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Thin, white, feathery ~ wispy.
Made of ice crystals
High – above 6000 m
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Different classifications of Clouds
Prefixes:
 Cirro – describes high clouds
 Alto – describes middle
 Strato – low
NIMBUS means “dark rain cloud”
**associated w/ precipitation
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Stratus cloud near ground!!
Air is cooled to dew point!!
Reduces visibility.
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Def: water in liquid or solid form falling from
atmosphere.
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1. Rain: water vapor forms raindrops when air
is WARM.
2. Snow: water vapor forms snowflakes when
air is COLD .
3. Sleet: Starts as rain but air near ground is
cold so rain freezes. (Made up of small ice
pellets.)
4. HAIL: Pellets of ice BUT they form INSIDE
the cloud.
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Sept. 22, 2010 Mrs. Edelen’s house!
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Compare
Contrast
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Role of WATER VAPOR in atmosphere
Relative HUMIDITY: tells whether day is dry
or precip. will happen.
Air Temp of Atmosphere: determines what
type of precip. will happen
Study Clouds: know what is coming
Understand the water cycle.
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There are …. SIX
 Wind ~ direction and speed
 Temperature
 Air pressure
 Humidity
 Cloud coverage
 Precipitation
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READ SECTION 1 (if you haven’t already)
Assignment:
P. 456 (1-10)