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Deadly Ascent

Classroom Activity


Activity Summary
To learn more about some of Earth's extreme environments and some of the possible dangers they present.

Learning Objectives
Students will be able to:

  • identify conditions of some of the world's extreme environments.

  • describe some of the potential dangers found in extreme environments around the world.

  • state some of the ways to deal with potential dangers in extreme environments.

Materials for each team
  • copy of the "Going To Extremes" student handouts (PDF 1, PDF 2 or HTML)
  • copy of the "Extreme Survival" student handout (PDF or HTML)
  • copy of the "Extreme Questions" student handout (PDF or HTML)

Climbers who ascend Denali (Mt. McKinley) can experience health problems in response to extreme conditions—high altitude, low atmospheric pressure, and severe cold. The mountain is 6,194 meters from its base to its summit. Most humans are adapted to living on Earth's surface where air pressure is about 14.7 pounds per square inch. At high elevations, because there is less oxygen in a given amount of air, humans who are not acclimated to the environment experience hypoxia, or oxygen deprivation, and its consequences due to low air pressure, and they experience health complications such as hypothermia, frostbite, and sometimes gangrene due to intense wind and cold. This chart shows some air pressures at different elevations:

(in meters)

Barometric Pressure*
(in centimeters)

Barometric Pressure*
(in Atmospheres)

0 (sea level)

76 cm


5,486 m

38 cm


10,668 m

18 cm


15,240 m

9 cm


18,288 m

5 cm


22,860 m

2.5 cm


28,956 m

.8 cm


* pressures are approximate

Mountains are only one example of extreme environments. Others include jungles, deserts, oceans, arctic regions, and space. In this activity, students wil l learn more about some of these environments.

  1. Distribute copies of the handouts to each student.

  2. Have students read the handouts and then answer the questions on their "Extreme Questions" handout. Ask for volunteers to share answers to each question with the entire class.

  3. As a class, categorize the dangers and risks presented for each environment. Discuss with students which of the dangers can become life threatening. Which dangers are avoidable? What could be most easily avoided? How? Which dangers seem unavoidable?

  4. As an extension, have students explore some of the scientific research being conducted in extreme environments, including environments not listed on the handout (i.e., in arctic regions, inside volcanic craters, and in space). Ask students to choose a research topic and create a poster that describes the environment's conditions, the research being conducted, and what scientists hope to learn.

Activity Answer
  1. Where are you likely to be vulnerable to both hyperthermia and hypothermia? Grand Canyon: hyperthermia from hiking (especially during summer months deep in the canyon), hypothermia from freezing nighttime temperatures (particularly during the winter months); Pacific Ocean: hyperthermia from extended sun exposure, hypothermia from cold nighttime temperatures or deep ocean dives; Denali: hyperthermia from overexertion, hypothermia from freezing temperatures.

  2. You have been bitten by an Anopheles mosquito and now have fever and chills. What's wrong with you and what should you do? You have malaria. If you didn't take chloroquine prior to your trip, you should see a doctor as soon as possible for antimalarial drugs.

  3. Oh your aching head. And dizzy body. And nauseous stomach. Luckily, a doctor is nearby. She diagnoses you with AMS. Where are you? Should you stay there or go somewhere else (and if so, where)? You are high on Denali. Your symptoms will go away if you descend to a lower altitude.

  4. Your brain tells you that the world looks nice and stable. Your inner ear says everything is pitching up and down. What's happening to you? You are suffering from seasickness or motion sickness.

  5. What is that taste in your mouth? Tastes like you bit into something rubber. You don't remember eating your bike tire, so what could it be? What should you do about it? You are reacting to the poison from a western diamondback rattlesnake bite. You should keep the bite area lower than the heart and place a constricting bandage between the bite and the heart before heading to a hospital.

  6. You are in the desert and have developed hyponatremia. What could you have done to prevent this? Hyponatremia (water intoxication caused by drinking too much water, which dilutes sodium in the bloodstream) can be prevented by reducing further intake of water and replacing the lost salt.

  7. Brrrrrr. It's really cold down here. You are 30 meters below sea level. Before you came down here someone told you to be careful about getting Caisson's disease. What is that? What other dangers do you face in this location? The person was referring to decompression sickness, or the bends, which is also known as Caisson's disease. This occurs when a diver swims to the surface too rapidly. Other dangers faced here include hypothermia and nitrogen narcosis.

  8. Snails may look pretty harmless when they are slithering by on your sidewalk. But there's one snail that you should avoid at all costs. Why would that be and where would you have to travel to find it? You would want to avoid the river snail because it causes schistosomiasis. It is found in Amazon rivers.

Links and Books

Web Sites

NOVA—Deadly Ascent
Find articles, interactive activities, and resources in this companion Web site to the program.

Desert Survival
Explains how to survive in a desert environment.

High-Altitude Medicine
Describes medical conditions that can occur in high-altitude environments.

Nitrox Scuba Diving
Reports on decompression sickness and potential remedies that lessen the effects of nitrogen when scuba diving.


Mount McKinley: Icy Crown of North America
by Fred Becky. Mountaineers Books, 1993.
Contains routes of specific Denali climbs, historical photos, a record of accidents, and an analysis of problems climbers have encountered.

Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance
by Kenneth Kamler. St. Martin's Press, 2004.
Details stories of human endurance in a jungle, a desert, the high seas, underwater, and outer space.


The "Going to Extremes" activity aligns with the following National Science Education Standards (see

Grades 5-8
Science Standard F

Science in Personal and Social Perspectives
Personal health
Risks and benefits

Classroom Activity Author

Developed by WGBH Educational Outreach staff.

Teacher's Guide
Deadly Ascent

Video is not required for this activity
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