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Science
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Ms.
Wagner
Wind
What is wind?
Wind is air in motion. It is produced by the uneven heating of
the earth’s surface by the sun. Since the earth’s surface is
made of various land and water formations, it absorbs the
sun’s radiation unevenly. Two factors are necessary to
specify wind: speed and direction.
What causes the wind to blow?
As the sun warms the Earth's surface, the atmosphere
warms too. Some parts of the Earth receive direct rays from
the sun all year and are always warm. Other places receive
indirect rays, so the climate is colder. Warm air, which
weighs less than cold air, rises. Then cool air moves in and
replaces the rising warm air. This movement of air is what
makes the wind blow.
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Ms.
Wagner
What are the global wind patterns?
The equator receives the sun's direct rays. Here, air is
heated and rises, leaving low-pressure areas behind. Moving
to about thirty degrees north and south of the equator, the
warm air from the equator begins to cool and sink. Between
thirty degrees latitude and the equator, most of the cooling
sinking air moves back to the equator. The rest of the air
flows toward the poles.
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Ms.
Wagner
What are the trade winds?
The trade winds are just air movements toward the equator.
They are warm, steady breezes that blow almost
continuously. The Coriolis Effect makes the trade winds
appear to be curving to the west, whether they are traveling
to the equator from the south or north.
What are the doldrums?
The doldrums is an area of calm weather. The trade winds
coming from the south and the north meet near the equator.
These converging trade winds produce general upward
winds as they are heated, so there are no steady surface
winds.
What are the prevailing westerlies?
Between thirty and sixty degrees latitude, the winds that
move toward the poles appear to curve to the east. Because
winds are named from the direction in which they originate,
these winds are called prevailing westerlies. Prevailing
westerlies in the Northern Hemisphere are responsible for
many of the weather movements across the United States
and Canada.
What are the polar easterlies?
At about sixty degrees latitude in both hemispheres, the
prevailing westerlies join with the polar easterlies to reduce
upward motion. The polar easterlies form when the
atmosphere over the poles cools. This cool air then sinks
and spreads over the surface. As the air flows away from the
poles, it is turned to the west by the Coriolis effect. Again,
because these winds begin in the east, they are called
easterlies.
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Ms.
Wagner
Beaufort Scale
The Beaufort scale is an empirical measure for the intensity
of the weather based mainly on wind power. The scale was
created by the British naval commander Sir Francis Beaufort
around 1806.
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Ms.
Wagner
Questions
1. Wind is _____________ in _________________.
2. Wind is produced by the _____________ _______________
of the ______________ ______________ by the _________.
3. The 2 factors necessary to specify wind are:
1)
2)
4. The wind blows because ____________ air rises, and then
_____________ air moves in and replaces the rising air.
5. The __________________ receives the sun’s direct rays.
6. Winds that move toward the equator are called
_____________________.
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Ms.
Wagner
7. The _______________ ________________ makes trade
winds appear to be curving to the ________________.
8. The areas of calm weather are called __________________.
9. Winds are named from the direction in which they ____________.
10. The winds between 30-60 degrees in both hemispheres that
move toward the poles are called _____________________.
11. Prevailing westerlies appear to be curving to the __________.
12. The ______________ _______________ in the
________________ _______________are responsible for
many of the weather movements across Canada and the
USA.
13. The winds 60 degrees and higher in both hemispheres are
called the _________________ _________________.
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14. When the prevailing westerlies join with the ______________
_________________, upward motion is _______________.
The polar easterlies form when the atmosphere over the
poles _______________. This cold air then _____________.
15. The scale that measures the intensity of winds is called the
_________________ __________________.
16. When small trees begin to sway, the Beaufort number
assigned would be a ______.
17. Winds that cause slight structural damage would be assigned
a ______ on the Beaufort scale.
18. Calm weather with a winds speed less than one would be
assigned a ______ on the Beaufort scale.
19. When wind is felt on your face and leaves rustle, the Beaufort
number assigned would be a ______.
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Wagner
20. Violence and destruction caused by a hurricane would be
assigned a ______ by the Beaufort scale.
21. When large branches of trees are in motion and whistling is
heard, the wind would be classified as a ______ on the
Beaufort scale.
22. When wind speed is between a 1-3 and there is a light air, the
Beaufort number assigned would be a ______.
23. A storm that has widespread damage will receive a ______
on the Beaufort scale.
24. When wind causes twigs and small branches to break off of
trees, the Beaufort scale number assigned would be a _____.
25. A gentle breeze where leaves and small twigs are in constant
motion and flags are flowing would be assigned a _____ on
the Beaufort scale.
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26. When small branches move and dust, leaves and loose paper
rise up, the Beaufort number assigned will be a _____.
27. When small trees begin to sway, the Beaufort scale will
assign the wind a _____.