Summary:
Students will investigate animal adaptations to a cold environment, specifically how they keep warm.

Materials:

For each student team:

• Four large, re-sealable ziploc plastic bags
• One pound of solid vegetable shortening (such as Crisco)
• Masking or duct tape
• A bucket, small aquarium, or plastic container (at least 25 cm deep) of cold water with ice cubes
• Watch with second hand or stopwatch
• Weights (e.g. stones)

Vocabulary

• blubber
• insulation
• impermeability
• rookery

Background For Teachers:

The wildlife of the Arctic and Antarctic are exquisitely adapted to withstand the harsh conditions of the polar regions. Penguins, seals, whales, walruses, sea lions and other large marine mammals that visit or live in this climate demonstrate features that help insulate these warm-blooded animals against the extreme cold.

One of the most effective thermal insulators for these creatures is blubber, a thick layer of fat found under the skin. Fur, another effective insulator retains heat in air pockets, but the air is released under the pressure of a dive. Blubber, however, does not compress under pressure. It also increases buoyancy and streamlines the body. These features make penguins ideally adapted for life in cold waters. Some species spend as much as 75% of their lives in the water, though they lay their eggs and raise their chicks on land. A streamlined body, paddle-like feet, insulating blubber, and feathers for waterproofing all add to their efficiency and comfort underwater. Heavy, solid bones act like a diver’s weight belt, allowing them to stay submerged. Their wings, shaped like flippers, help them “fly” underwater at speeds of up to 15 mph. They also have a remarkable deep-diving ability. In addition to blubber for insulation, penguins have stiff, tightly packed feathers (up to 70 per sq. in.), which overlap to provide waterproofing, coated with oil from a gland near the tail to increase impermeability. Their distinctive black and white shading makes them nearly invisible to predators from above and below. Like most birds, penguins have little or no sense of smell (a boon for those in a crowded penguin rookery!) Like other birds, their sense of taste is also limited. Scientists suspect they may be nearsighted on land. Their vision appears to be better when they’re underwater.

This simple activity helps students get a literal hands-on feel for an adaptation that lets penguins and other Antarctic animals survive and thrive in extreme conditions.

Instructional Procedures:

Download and screen “Happy Feet and Flippers” from the POLAR-PALOOZA website to show students penguins and the environment in which they live. Mention the average temperature in Antarctic summer, and winter (noting that these seasons are flipped from those we experience in the northern hemisphere.) The world’s record low temperature, minus 129 degrees F was recorded at Russia’s Vostok Station in the interior, though the coasts – where penguins live – are warmer.

Discuss how quickly our bodies are chilled in cold. Brainstorm ways in which penguins and other animals are well-adapted to cold water and icy environments (blubber, air in feathers, oil on fur, low surface area to volume ratio). Then complete the following demonstrations:

1. Flying birds need large wingspans to hold them up in the air, but small wings work best for birds that swim through water. Demonstrate this with two pieces of flexible card. Try to push a flat card through a pan of water. It’s difficult. Fold the second piece five or six times and then push that one through the water. The smaller, stiffer card moves through the water more easily.

2. Most birds have hollow bones that make their bodies light enough to become air-borne. But a penguin’s heavy, solid bones helps it float lower in the water. With the help of two student volunteers, demonstrate the difference between hollow bones and solid bones using two toilet paper rolls, one empty and the other stuffed with tissue paper.

3. Float an empty can in a bucket of water open end up. It floats high in the water like flying aquatic birds (ducks, for example). Add sand to another can until it sinks slightly. Now push down on both cans. The sand-filled container is easier to push down into the water, demonstrating how penguins can dive into water to find the food they need to survive, and to feed their chicks.

1. Divide students into teams of three or four. Have one student cover a hand with a plastic bag.
2. Have another team member place a generous amount of solid shortening into another bag and put the plastic-covered hand into the bag with the shortening. Knead the shortening to make sure the hand is completely covered by shortening.
3. Wrap duct tape around the section of the plastic bag covering the wrist area, so the bag is sealed (optional).
4. Cover the other hand with two plastic bags (without shortening). This is the "control."
5. Place both hands simultaneously into the container of icy, cold water.
6. Time and record how long each hand remains underwater.
7. Discuss what other advantages blubber gives marine animals besides warmth. (buoyancy)
8. Remove the bags from the student’s hands and seal the bags so water won't get in. Put the weights in the outer bag of each "glove."
9. Put the bags into the bucket of water. How much weight can each bag hold before it sinks to the bottom of the bucket?

Whales, Weddell seals, and penguins all have blubber. Discuss how the solid shortening is like the blubber that these Antarctic animals have.

Extensions:

1. Repeat the “blubber glove” experiment, but substitute alcohol thermometers or digital temperature probes in place of the student hands. Record the temperatures over several minutes and graph the temperature vs time results.

2. Remove the “control” bag from the ice water, blow air into the inner bag, carefully reinsert the thermometer or temperature probe into the bag, seal the opening, and place it back into the ice water. Avoid allowing the bulb end of the thermometer or the recording end of the probe to touch the surface of the inner bag. Record the temperature again over several minutes and compare the changes. What does the air in the bag represent? (air trapped inside of insulating feathers)

3. Penguin mail from the bottom of the world!
   Have your students create a self addressed and stamped post card about penguins. Make sure the postcard is no larger than 4.5 inches x 6 inches. Affix U.S. postage appropriate for a letter (41 cents) and send them to the address below by October 29, 2007. They will be hand carried to Antarctica and mailed back from the McMurdo Station in Antarctica. Space is limited, so send them early. For more information about the postcard and other penguin projects, go to :

   Penguin Science | Penguins Marching Into the Classroom
   Jean Pennycook
   Science Education Specialist
   c/o Fresno Unified School District
   3132 E. Fairmont #6
   Fresno, CA 93704

Bibliography:

Adapted from:

• Passport to Knowledge - Live From Antarctica II Teacher’s Guide p.39-40
• The Aquarium of Maine web pages
  • Penguin Adaptation
  • Blubber Glove

Author:
Utah LessonPlans

Created Date :
Feb 20 2008 12:51 PM