Grade 4 Science
Wk – 12 4/8
How do land features affect the water
cycle?
Sea Breezes and Land Breezes
Have you ever been to the beach on a hot day?
It might be so hot that your feet burn when you walk on the sand.
But when you go into the water, you quickly cool off.
That’s because the water is cooler than the sand.
Land heats up much more quickly than water. Land also
cools down more quickly than water.
Because of this, the temperature of the air over land is
almost always different from the temperature of air over
nearby water.
During the day, the air over water is cooler than the air over land.
The hot air over a beach is pushed upward by the cool air moving in
from over the water. This causes a sea breeze.
A sea breeze is a breeze moving from the water to the land.
What causes a sea breeze?
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During the night, the land becomes cooler than the water. This
causes a land breeze.
A land breeze is a breeze moving from the land to the water.
http://www.youtube.com/
watch?v=gM0d3fGew0&feature=related
What causes a land breeze?
Sea breeze storms
Sometimes, cool sea breezes push clouds toward the shore. The
clouds can then produce storms over the land. These storms are
called sea breeze storms.
http://www.youtube.com/watch?
v=cmIVRgaKmsc
Rain shadows
Shorelines are not the only landform that affects the water cycle.
Mountains do too. Suppose a moving body of air hits the side of a
mountain range. What happens? The air moves up and condenses,
then it rains. By the time the air reaches the other side, it is dry.
So it doesn’t rain on the other side. This causes a rain shadow.
A rain shadow is the area on the far side of a mountain that does
not get rain.
Wet side: as air is
pushed upward, it cools
and releases its moisture.
Dry side: as the cool
air moves downward,
it warms and dries
out as it spreads over
land.
What is the effect of a rain shadow?
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Lightning and thunder
Lightning jumps from cloud to cloud, or from cloud to the ground. If
there are tall buildings, the lightning will often jump from the
clouds to the buildings.
The next time a thunderstorm is in your area, watch for lightning.
When you see the lightning, start counting, “one….two…three…”.
when you hear the thunder, stop counting. For every three seconds
you count, the thunderstorm is about one kilometer from you. How
far away is the thunderstorm?
Draw a sea breeze (daytime)
Draw a land breeze (night time)
Draw a rain shadow and it’s effect
My Dictionary
sea breeze: ______________________________________
land breeze: _____________________________________
rain shadow: _____________________________________
lightning: _______________________________________
thunder: ________________________________________