NOVA

Lost on Everest

Student Handout

Keeping Warm

Survival in cold weather depends on the ability to preserve body heat. Here's a chance to test different fabrics and your assumptions about which ones insulate best, and therefore, best keep you warm. You and your classmates will build models of mountain climbers and dress them in different fabrics to protect them in freezing temperatures.

Procedure

  1. Use a measuring spoon to pour 1 teaspoon (about 5 milliliters) of room temperature water into a balloon to represent the body's "core heat."

  2. Slide a laboratory thermometer into the balloon so that the bulb nearly reaches the bottom of the balloon; the water should cover the bulb. Carefully seal the balloon to the thermometer with a rubber band.

  3. Tape a tongue depressor to the thermometer so that the end of the depressor sticks about 3/4-inch (2 centimeters) below the balloon bottom. Draw a face on the depressor to give your explorer some personality, and write a name on the bottom.

  4. Snugly wrap a single layer of test fabric around your explorer, stapling it on the back side of the depressor. If your climber will be wearing a wet fabric up the mountain, moisten the fabric with water. Record the starting core temperature.

  5. After farewell wishes, place your dressed explorer in one of the milk carton holders provided by your Sherpa/Sherpanni (teacher), who will take them up the mountain (into the freezer).

  6. While the climbers are enduring freezing temperatures, discuss which fabrics you believe will preserve heat best and why. Make a class chart that includes:

    • climber name

    • fabric type

    • fabric condition (dry, wet)

    • starting temperature

    • temperature when returned

    • temperature change

    • insulating quality (poor, fair, good, excellent)

  7. When your climbers return from the freezer, quickly record their temperature and subtract it from the starting temperature. Put the temperature difference in the temperature change column of the chart. As a class, determine the insulating quality of the different fabrics.

Questions
Write your answers on a separate sheet of paper.

  1. What did you notice about your results?

  2. Which fabric types were the best and which were the poorest at preserving heat? Why do you think so?

  3. What did you learn about dry versus wet fabrics in cold, windless conditions?

illustration of  laboratory explorers and milk carton


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