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Lost on Everest

Classroom Activity


Objective
To determine how effectively common clothing fabrics insulate against cold.

Materials for each team
  • copy of "Keeping Warm" student handout (HTML)
  • small round balloons
  • bowl of room-temperature water
  • measuring spoons
  • laboratory-style thermometers
  • rubber band
  • tongue depressors
  • fine-tip markers
  • scraps of fabric assigned to that team
  • staplers and tape
Materials for teacher
  • half-gallon milk cartons
  • cardboard box large enough to transport all milk cartons
  • towel
  • scissors or sharp knife
  • freezer access
Procedure
  1. Read the "Keeping Warm" student handout to familiarize yourself with how students will make their climbers.

  2. Prepare enough milk carton holders so each will hold no more than six climbers. Cut off the tops and cut large windows in the lower half of each carton.

  3. For this experiment to be successful, there needs to be a range of results among the different fabrics. Run this experiment ahead of time in your freezer and check frequently to determine the time period that gives you the broadest spread of temperatures. Use this time frame when doing the experiment with your students.

  4. Choose a variety of different fabrics, such as wool, cotton, corduroy, polar fleece, and denim for students to test. Because it takes about 30 minutes to prepare the climbers, consider setting up the experiment one day and running it the next.

  5. Discuss with students how to best run the experiment to compare the insulating ability of different kinds of fabrics, both wet and dry. Assign students to teams and give each team a copy of the "Keeping Warm" student handout and a fabric and condition (wet/dry) to be tested. Discuss the variables involved in the experiment and how to best control them.

  6. Have students make their climbers and record starting "core" temperatures on their thermometers. Place the climbers in the freezer and note the time. Remove them at the time you determined in your pretrial.

  7. Prepare a class table of all data, directing students to group data for samples of the same fabric. Focus their discussion on traditional versus modern fabrics. How might the fabrics have been similar? How might they have been different?

Activity Answer

This activity explores the insulating ability of different materials. It does not take into account body heat, however, which helps real climbers stay warm. How much body heat a person generates depends on many factors, including the amount of body fat and the number of calories a climber has consumed. How much oxygen climbers receive is also a factor in their ability to keep warm (at high altitudes, where the air is thinner, climbers often become oxygen-deprived and rely on bottled oxygen for support).

There are many factors that can cause the end temperatures to be different for samples of the same fabric. These include different temperatures within the freezer, different volumes of water in the balloons, and tightness of the fabric around the explorer. This is a good place to discuss tight control of variables.

Flat, polished fabrics tend to trap less air than puffy fabrics with ample loft. Wool and spun polypropylene will perform well, while silk will do poorly if worn alone. Cotton, like that in blue jeans, should be avoided as it absorbs and retains water and can be difficult to dry. Most wet fabrics let heat escape quickly.

In cold conditions, it is best to layer clothes with several different types of fabrics. According to Princeton University's Outdoor Action Web site, the purpose of layering is to be able to mix and match the layers of clothes to match the weather conditions and your activity level. The idea is to maintain a comfortable body temperature without excess sweating, which increases heat loss.

Hydrophobic synthetic fabrics, such as polypropylene, move moisture away from your body to help keep you dry, according to the Princeton University site. Even if you get wet, wool or synthetic pile/fleece fabrics will keep you warm because they don't absorb water. In addition, windshells made of nylon or nylon/cotton blends reduce convective heat loss.

The comparison of traditional fabrics versus modern fabrics is important. Wool and fur trap air, thus maintaining a bubble of warm air around the body and minimizing heat loss. Some modern fabrics are lightweight, waterproof, and windproof, but they need a puffy inside layer to trap the air around the body.

You may want to mention to students that temperature is only one of the factors with which climbers must contend. They also must deal with wind, fog, and sun, all of which can influence temperature.

The following is a set of sample data results for one trial run of the activity.

Fabric

Minutes



2*

4*

6

8

10

12

14

dry denim

-3.0

+0.5

-11.0

-14.0

-16.0

-19.5

-22.5

wet denim

-4.0

0

-12.5

-15.0

-16.5

-19.5

-22.5

polar fleece

-3.9

+3.5

-8.5

-9.5

-11.5

-15.0

-17.0

melton wool

-3.5

+3.0

-8.5

-11.0

-13.5

-16.5

-18.5

faux fur

-3.8

-6.8

-7.8

-9.8

-11.8

-14.8

-17.3

*Temperatures may be initially unstable because of a differentiation of warm and cold air pockets within climbers' clothes; this should normalize after a few minutes in the freezer.
Links and Books

Books

Science Projects About Temperature and Heat by Robert Gardner and Eric Kramer, Springfield, New Jersey: Enslow Publishing, Inc., 1994.
Describes several activities for investigating the insulating properties of different materials.

First on Everest: The Mystery of Mallory and Irvine by Tom Holzel and Audrey Salkeld, New York: Henry Holt and Company, 1986.
Explores the Everest expeditions of the 1920s and describes in detail the 1924 expedition where Mallory and Irvine disappeared.

Article

"A Body on Mt. Everest: A Mystery Half-Solved" by Christopher Wren, The New York Times, 5 May 1999.
Describes the discovery of Mallory's body by American climbers 75 years after Mallory and Irvine disappeared climbing Mt. Everest.

Web Sites

NOVA Online—Lost on Everest
http://www.pbs.org/nova/everest/lost/
Delves deeper into the program's content and themes with features such as background information on Mallory and Irvine, photographs of the evidence collected during the expedition, program transcripts, and timelines of attempts to climb Mt. Everest. Launch date: Friday, February 14.

Mallory and Irvine Research Expedition
http://classic.mountainzone.com/everest/99/north/
Details the Spring 1999 expedition to determine the fate of Mallory and Irvine. Includes interviews with members of the expedition team and a daily journal entry. Click on dispatches to see the archive of all journal entries.

Princeton University's Outdoor Action Guide to Hypothermia and Cold Weather Injuries
http://www.princeton.edu/~oa/safety/hypocold.shtml
Learn how humans lose body heat to the environment and react to cold weather.

Standards

The "Keeping Warm" activity aligns with the following National Science Education Standards and Curriculum and Evaluation Standards for School Mathematics:

Grades 5-8

Science Standard A:
Science as Inquiry

Abilities necessary to do scientific inquiry

  • Design and conduct scientific investigations.

  • Use appropriate tools and techniques to gather, analyze, and interpret data.

  • Think critically and logically to make the relationships between evidence and explanations.

Physical Science

Science Standard B:
Physical Science

Transfer of Energy

  • Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature.

Grades 9-12

Science Standard A:
Science as Inquiry

Abilities necessary to do scientific inquiry

  • Design and conduct scientific investigations.

  • Use technology and mathematics to improve investigations and communications.

Teacher's Guide
Lost on Everest
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