show #1202
- Do fabrics differ in their ability to keep the wearer warm and dry?
- Which is more important in frigid temperatures--keeping dry or staying
warm?
David learns how to keep warm and dry in the Arctic with explorer Will Steger.
Segment length: 26:40
Contents
Blustery winds whirl around the explorers as they pitch their tents. They've just
finished ten hours of sweat-producing activity--skiing and dog sledding in frigid Arctic
conditions. But these people stay warm and dry, thanks to specially designed clothing
and high-tech fibers.
To decide which synthetic fabrics to
wear, explorers need to decide what they want their protective clothing to do. If they
want it to repel water but still "breathe," they might choose fibers such as nylon or
polyester or waterproof, breathable laminates and coatings. Many fabrics contain a
combination of fibers. For example, if your jacket has hydrophilic (water-loving)
fibers on the outside and hydrophobic (water-fearing) fibers near your skin, the inner
fibers will push moisture away from your skin while the next layer of fibers will pull
the moisture outward.
Keeping dry is as important as keeping warm when it comes to survival and comfort in the
Arctic. An adult normally loses about one liter of water a day through evaporation from
the skin and lungs. During a day of strenuous activity, a person can lose ten liters of
water. As the body burns energy during physical exertion, it creates heat. It then
produces sweat, which provides a cooling effect as it evaporates. A sweaty person in
wet clothes can lose heat rapidly if inactive in frigid temperatures.
Each member of Will Steger's team will wear five layers of clothing that
provide insulation. Explorers can peel off or put on
layers as weather conditions and activity levels change. The first layer consists of
long underwear made of a lightweight, synthetic material that allows perspiration to
move away from the skin to the second layer, a synthetic fleece shirt and pants. As it
wicks moisture away, the quick-drying fleece helps the
underwear layer provide warmth.
Next, a jacket covers the first two layers, offering insulation. Made of a heavier
fleece designed for use in extreme cold, the jacket has two-way underarm zippers
(as do garments in the top two layers) to help the explorer regulate body temperature.
The fourth layer, a lightweight second jacket made of very fine, tightly woven
microfibers, slows the rate of moisture loss. The final layer--a durable storm shell that
is waterproof and breathable--protects against wind, rain, and snow. The shell is
laminated with a film containing microscopic pores that allow water vapor (sweat) to
escape while keeping moisture out.
Team members also wear mukluks, flexible boots designed by the Inuit people and made of
animal hides and canvas. Sled dogs, too, wear booties as protection from rough ice and
snow.
- What fabrics do you normally wear? Which are the warmest and which keep you
cool? Do some fabrics allow more air movement than others?
- What difference does a hat make in regulating body temperature? Do you
notice a difference when you take off a hat you've worn for several minutes?
- Which parts of the body make up its "heating core"?
insulation a material or fabric that helps a
person retain heat
layering a system of wearing clothes in layers to
provide maximum warmth and dryness. An effective system allows a person to adjust for a
wide range of climatic conditions.
microfibers very thin fibers tightly woven. They trap
warm air in clothing and cut heat loss.
moisture loss moisture lost through pores in our
skin and through our noses and mouths as we breathe
sythetic fabric material made from fibers that do
not occur naturally. Nylon is an example.
wicking the act of absorbing moisture and moving it away.
A fabric that wicks perspiration absorbs sweat on the skin and moves it to an outside
layer of material, leaving the fabric next to the skin relatively dry and helping the
person stay warm.
- Brody, H. (1987) Living Arctic: Hunters of the Canadian North. Seattle: University
of Washington Press.
- Forgey, W.W. (1985) Hypothermia. Merrillville, IN: ICS Books, Inc.
- Getchell, D., et. al. (1993, Sept) Wild clothes: 1993 guide to functional
outdoor apparel. Backpacker, pp. 61-80.
- Randall, G. (1994) The modern backpacker's handbook. New York: Lyons & Burford.
- Sierra Club, San Diego Chapter. (1993) Wilderness basics: The complete handbook for
hikers and backpackers (2d ed.). Seattle: The Mountaineers.
- Townsend, C. (1994) Wilderness skiing and winter camping. Camden, ME: Ragged
Mountain Press.
- Wilkinson, E. (1992) Snow caves for fun and survival (rev. ed.). Boulder,
CO: Johnson Books.
Additional sources of information
American Textile Manufacturers Institute
1801 K Street NW, Suite 900
Washington, DC 20006
(202) 862-0500
Institute of Textile Technology
2551 Ivy Road
Charlottesville, VA 22903-4614
(804) 296-5511
Community resources
Specialist at an outfitter company
Fabric store
Store that sells camping gear and outdoor clothing
People lose moisture through evaporation from pores in the skin. When you're hot and
begin to sweat, your rate of respiration speeds up in an effort to cool your body. Skin
moisture can evaporate rapidly in a dry climate, even when you're not sweating. On
average, an adult loses about one liter of water a day. When working hard and burning
energy that produces heat, that person's water loss quickens proportionately. Create a
lab that demonstrates aspects of water loss from your body.
Materials
- one plastic bag per student, or plastic wrap
- scissors
- masking tape
- paper and pencil
- Cut the plastic bag into a single-layered square large enough to fit
comfortably around your forearm. Place the piece of plastic around your forearm and
tape it securely (but not too tightly) at top and bottom.
- Wear the plastic over your forearm for at least ten minutes. Meanwhile, in teams
of four people, take and record your pulse and respiration rates. Then walk up and down
a flight of stairs five times. Record your new pulse and respiration rates. Next, run
up and down the stairs five times and then record pulse and respiration. (If your
school has no stairs, use a hallway or a walkway outside.)
- After the exercise, note whether the plastic contains any water condensation
released by your skin as it performed respiration and perspiration.
- Take the bag off and feel the moisture on your skin where the plastic had
been. Note the moisture level of the skin that was under the plastic as compared to
skin exposed to air during the ten minutes.
Questions
- What is the effect of moisture evaporating on your skin?
- How much fluid does a person need to consume each day to replace regular moisture
loss?
- Do we lose only water, or do we lose other essential elements through
evaporation as well?
TRY THIS!
Investigate the materials used to make your outer jackets and clothing. At home, read
the fabric labels on your jackets and outerwear, and write down the materials listed.
Report to the class which fibers your clothing's fabric contains. Add to your list the
contents of any other fabrics worn by your classmates.
TRY THIS!
Invite a representative from an outfitters or outdoor equipment store to discuss
characteristics in fabrics that make the materials lightweight, provide warmth and
insulation, and wick moisture. Examine clothing samples that demonstrate these
characteristics.
TRY THIS!
Discuss the factors that affect windchill. Identify how windchill is created. What
effect does it have on your body's ability to stay warm in cold weather?
TRY THIS!
Look through camping books, catalogs, and magazines to find references about materials
used in boots, sleeping bags, packs, and other outdoor equipment. List the materials
named in these articles and advertisements. What characteristics were cited as the most
valuable?
To receive the entire 12th season NEWTON'S APPLE Educational Materials packet please
write:
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Newton's Apple is a production of KTCA Twin Cities Public Television. Made possible by a
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