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Winds
And
Weather
by Jonas Ramoth and Sidney Stephens
Activity Series 3 - Topography
"The west wind is a poor artist
but the east wind does beautiful work. "
Jonas Ramoth
Background |
Jonas Ramoth says that in Selawik, the
west wind is a poor artist while the east wind does beautiful work. This
refers to the fact
that the west wind creates messy, rough, uneven piles of snow while the
east wind leaves long, straight drifts of snow about 10 - 12" wide in
flat country. Part of the explanation for this is local topography. (Prevailing
global wind patterns are also significant. See Activity Series 5 - Global
Winds). Selawik is located in a valley on low-lying tundra, at the base
of the Kobuk River Valley to the east and facing Selawik Lake and Kotzebue
Sound to the west. The valley acts as a funnel for prevailing East winds
which create long, straight drifts of snow in the winter, while the broad
winds generated from the west are interrupted by minor hillocks or trees.
This frictional contact re-routes the wind creating characteristic rough,
uneven drifts. |
Activity 3a
Materials |
1-meter stick and clipboard per pair of students, graph paper
|
Preparation |
Select a building that demonstrates a variety of drift patterns
due both to the prevailing winds and frictional contact with obstacles.
A square building is the best because it creates the most predictable wind
eddies. The best grounds are flat and bare, extending for a sizable distance
in all directions from the building. Try to avoid areas that have been shoveled
or cleared mechanically. |
Procedure
Apply/Gear-up |
1. Jonas has said and you have observed that the west wind is a poor
artist but that east wind does beautiful work. What does he mean by this?
Have you noticed the two kinds of drift patterns he describes? Where?
What are your ideas about why this might be so? (EA - prior knowledge)
|
Explore |
2. In pairs, station students equally spaced around the perimeter
of the building. Have them check and record the snow dept right next to
the building by inserting a meter sick straight down into the snow until
it hits the ground. The next reading should be taken two feet further from
the building, on an imaginary line that is perpendicular to the building.
If possible, have them take as many as 15 readings in this fashion. |
Generalize |
3. Upon return to class, have each team construct a graph of their snow
bank as it would appear in profile - as if they sliced it in half and
looked at if from the side. To make later comparisons easier, establish
a universal scale for these graphs. (Note - students could collect data
right on the graph paper, creating this profile as they measure drift
depth and save this transfer step)
4. Tape the graphs on the classroom wall surrounding a diagram of the
building that is properly oriented for compass directions.
5. Combine teams into discussion groups of 4
students each. A team for one side of the building might be combined
with a team from another
side. Have them discuss their two graphs and try to account for the differences
between them. Each group should prepare a list of differences in the
drifting
pattern (depth, length etc.) between the two sides of the building, and
try to account for these differences to the class. When they give reasons
for the differences, listen for reference to wind, wind direction,
wind
speed, obstacles, and so forth.
|
Activity 3b
Materials
|
Per team: 2-ft wooden stick, 2 large pieces of poster board, tissue paper,
tape, scissors, electric fan, 4 bricks
|
Procedure
Explore
|
1. If your students already understand that the mountains to the east
of Selawik (and sometimes buildings) act as a funnel, provide them with
the materials and challenge them to demonstrate the funnel effect. If
not, you might guide them through the process below:
« Cut the tissue paper into strips 1/2 inch wide
and 1 ft long. Tape the strips by their ends to one end of the wooden
stick.
« Place the fan on a table and switch on to its low
setting to make a light breeze. Hold the stick, with the strips at
the top, a short way
from the fan. How high does the breeze blow the strips?
« Now make a narrowing valley from the poster board
and the bricks, with the fan at the wide end and the stick near the
narrow end. Turn on the
fan to the same setting as before.
« Play with the width and length of valley to see
if it changes wind speed
|
Generalize |
3. How strong was the breeze without the
poster board? With the poster board? How did the shape of the "valley" influence
wind speed? What are your ideas about why this might be so? (A valley
or canyon acts
as a funnel to wind blowing along it. Wind speed increases and air pressure
may fall.) |
Explore/
Generalize |
4. Challenge students to construct a model of the building
they surveyed for snow drifts and use the fan/wind strips to gauge the wind
speed at different points. |
Activity 3c
Materials |
Per team, a baking pan 2-6" deep, water, modeling
clay to create obstacles above the surface of the water, buoyant spice
powder
|
Procedure
Explore/
Generalize |
1.Stick towers of clay along one side of the dish to represent buildings,
a group of large trees or hillocks. Pour enough water into the dish to
cover the bottom at least an inch.
2. Sprinkle spice powder at one end of the dish, away from the obstacles.
Tilt the tray and watch the powder to see how the "wind" moves around
obstacles. (Obstacles deflect winds making complicated patterns as the
air eddies around them. As wind is deflected, it also slows, mainly because
of friction between the air and the surfaces it passes.)
|
Activity 3d
Materials |
Per group: 8 x 2in cardboard, modeling clay, matches, small candle, saucer
|
Procedure
Explore/
Generalize |
1. Place candle on saucer, using a blob of modeling clay to support it.
Light the candle.
2. Hold the cardboard "building" upright 4 inches
from the candle. Blow hard directly at the building. Behind the shelter
do you think the wind
will blow toward the building or away from it? Watch what happens to
the flame.
3. What are your ideas about why this might be
so? (When wind blows at right angles to a building, the air will form
eddies around the building
and the flame will lean, temporarily towards the cardboard).
|
Apply/Assess |
4. Tell students that they have been out ice fishing on Selawik Lake
but that visibility has decreased and they have lost their orientation
to the hills and town. Ask them how they might use their knowledge of
drift patterns to find their way home.
5. Provide students with a diagram of a river
with eddies and ask them to explain the formation of eddies based on
their study of wind.
6. Ask students to bring in scrap materials from home (bottles, pieces
of wood etc) and challenge them to create a specific kind of snow drift
based on their understanding of the effects of wind on snow. You might
ask them to create a very long or wide or deep drift or a drift that digs
a very deep hole n the snow.
7. Select several sites around town, take field trip to each of them,
and ask students to described how /why the chosen drifts were formed.
|
Standards
Section I - Observing Locally
Section II - Understanding Wind
Section III - Connecting
Globally
Appendix A - Selawik Weather Information from
Jonas Ramoth
Appendix B - Assessment
Appendix C - Weather Resource
List
Appendix D - Interdisciplinary Integration
Handbook
for Culturally Responsive Science Curriculum by Sidney Stephens
Excerpt: "The information and insights contained in this document will be
of interest to anyone involved in bringing local knowledge to bear in school
curriculum. Drawing upon the efforts of many people over a period of several
years, Sidney Stephens has managed to distill and synthesize the critical ingredients
for making the teaching of science relevant and meaningful in culturally adaptable
ways." |