Download Chapter 7, Lesson 4

Chapter 7
Weather and Climate
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Define climate in terms of
temperature and precipitation.
Describe the factors that affect
climate.
A region’s average weather pattern,
which can change over time,
determines its climate.
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rain shadow – a region on the side
of the mountain where air becomes
dry and descends
sunspot – a dark area that appears
temporarily on the sun’s surface
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Climate is the average weather
pattern of a region.
Climate may vary from season to
season.
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Latitude or distance from the equator
effects climate due to insolation.
Tropical zones, equator to 30° N or S,
tends to be hot and wet.
Latitudes around 30° are often hot
and dry.
Between 30° and 60° summers are
warm and winters cold.
Draw Conclusions
What type of plants might live in
areas of low precipitation?
Plants that live in areas of low
precipitation have adapted to dry
conditions, such as cactuses that can
store water.
Critical Thinking
How would you dress for a trip to
the South Pole?
Polar regions are cold and dry. Dress
to stay warm, because the body will
lose heat quickly there. Clothing that
is in layers will help conserve heat.
Layers are important because, if you
do become warm enough to sweat,
you can remove some of the layers.
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Temperature and precipitation are
the two main factors.
Temperature can be affected by
latitude, distance from water, ocean
currents, winds, altitude, and
mountain ranges.
Regions within a large landmass have
a Continental climate.
 Hot summers,
 Cold winters,
 And low precipitation.
A maritime climate can be found by
large bodies of water.
 Warm summers
 Mild winters
 And high annual rain fall
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Global winds move water in currents
across the surface of the ocean.
 Areas near warm currents tend to
have warm temperatures.
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The prevailing winds that blow west
to east push air masses and fronts
across the United States.
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At higher elevations there is less air
pressure therefore the air has less
energy which means it will be cooler.
Mountain ranges block much of the air
from passing by them.
Rain shadows are created when winds
blow clouds up a mountain side and
rain.
 The leeward side receives the dry air.
Dust, ash, and gases from erupting
volcanoes can block sunlight, causing
a cooling effect.
Draw Conclusions
Suppose you live on the windward
side of a coastal mountain range.
A warm current flows along the
coast. Describe the climate of
your region.
The climate would be warm,
moist, and rainy.
Critical Thinking
As you climb a mountain, you may
pass through several climate
zones? How is this possible.
As you climb up the mountain it
becomes colder due to the low
air pressure.
The lower pressure and lower
temperatures cause changes in
the climate.
Evidence suggests a climate change
due to variations in sunlight and
plate tectonics.
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The energy output of the Sun varies.
The Sun has a sunspot cycle every
11 years, which is related to the
Sun’s magnetic field.
 During sunspot activity the
Earth’s average temperature rises.
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Fossil evidence tells us that very
cold areas were once closer to the
equator.
Draw Conclusions
Scientists have learned that northern
Europe once had a warm, wet climate.
What led scientists to draw this
conclusion?
Fossil evidence and evidence of plate
tectonics are proof that northern Europe
was once closer to the equator.
Critical Thinking
What changes in the Sun might
account for warm periods in
Earth’s history?
Warm periods might have been
caused by an increase in the Sun’s
brightness or in sunspot activity.