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Chapter 7
Lesson 2
SPI’S:
5.1.8, 5.1.9, 5.1.2, 5.1.26, 5.1.31.
5.1.3, 5.1.4, 5.1.6, 1.1.3,
(Science, SS, Language, Reading)
Let’s Start with Tornadoes:
Tornadoes are the fastest winds on earth.
They are concentrated, swirling winds
that can cause great damage.
Remember, we learned in the lesson
on climate that the sun heats the earth
unevenly.
The uneven heating of earth plays a
role in the forming of thunderstorms
and tornadoes.
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Most common in spring and summer
Form in warm, moist air ahead of an
advancing cold front.
They begin as a horizontal column of
spinning air, then are lifted into a vertical
column by the updraft of a thundercloud
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Tornadoes typically do not strike the
centers of large cities.
Heat from cities prevents tornadoes from
forming.
The path of a tornado is difficult to
predict precisely.
As winds change, tornadoes may change
direction.
Who’d like to read this selection
on P. 252?
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Air mass
Atmosphere
Front
Mesosphere
Stratosphere
Thermosphere
Troposphere
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Air mass – huge volume of air
responsible for certain types of weather
in a given area.
Atmosphere – mixture of gases that
surrounds Earth, made mostly of the two
gases; nitrogen and oxygen.
This mixture of gases forms 4 main layers:
thermosphere
mesosphere
stratosphere
troposphere
Look on P. 257 for illustration of Earth’s layers
Let’s read more about air mass and
atmosphere on
PP. 256 – 258?
Front - a boundary between two air masses,
with different properties.
Let’s read more about “Fronts” on P. 259
(It will help this definition make more sense.)
How do air masses affect weather?
They bring different conditions as they
move into an area.
When does a cold front form?
When cold air moves into an area, forcing
warm air to rise up in the atmosphere.
(Look at the illustration on P. 259)
Using the map key, what is the temperature in
the following cities:
Nashville
St. Louis
Houston
Boise
Chicago
Boston
Let’s read pp. 261 & 262 to
see if we can find two types
of weather data that can be
observed with radar.
Precipitation, and the size,
speed, and direction of a
storm.
How does the radar image of
Hurricane Charley help
verify that the eye, or center,
of a hurricane is calm?
Radar picks up signals
indicating precipitation. The
eye of the hurricane is empty,
which shows there is no rain.
Why are weather satellites an
important tool for weather
forecasters?
They orbit high above Earth
and can track large storms.
(IRAS) Infra-Red Astronomical Satellite
1983.
What is an air mass, and
what determines its
properties?
An air mass is a large
volume of air that forms in
the troposphere. Its
properties depend on where
it forms.
How are cold fronts and
warm fronts similar and
different?
Cold fronts and warm fronts
both bring a change in the
weather. Cold fronts bring
cold air, and warm fronts
bring warmer air.
Suppose our area is
experiencing thunderstorms.
What kinds of changes in the
atmosphere led to the
formation of the storms?
A cold front moved into the
area, forcing warm air up
into the atmosphere. Clouds
then formed and dropped
heavy rains.
Explain how radar images
can help to reduce damage
from an approaching storm.
With adequate warning,
people would have time to
board up windows, secure
outdoor items, and evacuate.
Be sure to review your notes
over chapter 7. The test date
will be announced soon.
In the meantime…
STUDY, STUDY, STUDY!!!