TIME: Because of time requirements, this activity is probably best done as a homework project. With students working in teams of two, snow pile construction takes 1-3 hours, setting takes 2-3 hours, tunneling takes 1 hour, and data collection takes 2 hours. See optional pre-lab class activity on next page.
ADVANCE PREPARATION: This activity depends upon a recent snow accumulation of at least 30 cm of light, fluffy snow. You may wish to order the film, "Nanook of the North" (by Robert Flaherty, b/w 1922, McGraw Hill-Gregg Division, P.O. Box 404, Princeton Road, Hightston, New Jersey 08520) or rent "Never Cry Wolf" (1985, Disney Productions) for class viewing
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PREDICTION:
In class discussion, encourage creative, logical, and critical thinking. We recommend that you introduce the following ideas if they are not suggested by students: The temperature of an empty quinzhee will remain about -2oC even if it is -40oC outside due to heat transfer from the ground. If the quinzhee contains people, perhaps with a stove or candle, the air temperature may become even warmer (2 to 7oC).
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PROCEDURE: Since this activity will probably be done at home, it is most important that you explain the project thoroughly. Remind students to make a large enough snow pile, and to "loft" the snow as they shovel to avoid packing. Emphasize that proper clothing is a must. Suggest that they layer their clothes; they will probably need to remove some layers as they work to avoid overheating
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SAFETY NOTE:
Warn your students never to tunnel into a snowpack formed by snowplows
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SAFETY NOTE:
Encourage students to follow directions carefully, especially regarding the thickness of the roof and walls (although there is little danger to healthy adolescents if the quinzhee collapses). A PROPER VENTILATION SHAFT IS A MUST whenever students spend time in the quinzhee
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STEP H:
If maximum-minimum thermometers are available when students sleep in the quinzhee overnight, place one inside and the other outside the quinzhee. Compare the minimum temperature outside to the minimum temperature inside
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OPTIONAL PRE-LAB ACTIVITY:
Construct a small mound of snow (about 0.5 m tall and 1.0 m in diameter) at least 2-3 hrs before class in a nearby open area. Be sure to mix snow from the surface and bottom of the snowpack, lofting the snow as the pile is made. In class, have several students make a similar fresh pile of snow beside the old pile. After the students have completed their snow mound, select two students of similar size. Have each student carefully sit, and then stand, on the mounds. The fresh mound will collapse immediately. Your old mound should be very hard and will probably support the student's weight.
Ask the class for an explanation. Tell them that water vapor in the snowpack tends to move from warmer snow (sublimation) to colder snow (deposition). When a quinzhee is constructed, warm snow near the soil is thoroughly mixed with cooler snow near the surface of the snowpack. Water vapor from warmer snow crystals moves to cooler crystals nearby, fusing or sintering the crystals together. The fresh mound of snow becomes hard enough to make a sturdy snow shelter.
QUESTIONS 5-13 require higher order thinking skills. We recommend that you discuss these questions in class (and view student photographs or sketches) before having students write out their answers
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2.
Freshly mounded snow should have more broken crystals and smaller air spaces than undisturbed snow
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3.
Snow in the completed quinzhee should have larger crystals fused together
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4.
The warmest air not next to a heat source should be at the top of the quinzhee since warm air rises. The coldest air should be near the ground, especially near the vent
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5.
The snow crystals were fused together
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6.
No, because there would not be large temperature gradients to harden the snow
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7.
Since warm air rises, it will pass out the vent at the top of the quinzhee. If the other vent is not near the base, the air inside the quinzhee will not be replaced completely with circulating fresh air
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8.
Your body heat was held within the quinzhee
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9.
The ground is a heat source. During summer, the ground stores the heat from the sun and gives off this heat during the winter
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10.
If snow is left on the ground, it will insulate the ground heat source from the air inside the quinzhee
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11.
The insulation value of snow is related to its density. Loose snow has more dead air spaces to retain heat inside the quinzhee
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12.
Mammals: Snowshoe hare, cottontail may spend the night in temporary burrows beneath the snow. Birds: Northern grouse, including the ruffed grouse, may fly into light snow pack and then spend the night in a temporary burrow which they create. Snow buntings and red polls are known to bed beneath the snowpack at night
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13.
Answers will vary.