How do Antarctic animals stay warm in bone-chilling water?
- Discuss how quickly our bodies are chilled in cold water. What do we do to stay warm? (move around, wear insulating wetsuits, get out of the water).
- Ask students to list ways in which animals are able to stay warm in cold water (blubber, air in feathers, oil on fur, low surface area to volume ratio).
- Have the students cover one hand with a plastic bag.
- Put a generous amount of solid shortening into another bag. Have the student put the plastic-covered hand into the bag with the shortening. Knead the shortening to make sure the hand is completely surrounded by shortening.
- Wrap duct tape around the portion of the bag covering your wrist to seal the bag (optional).
- Cover the other hand with two plastic bags (without shortening). This is the "control."
- Place both hands simultaneously into a bucket of cold water.
- Have a student time how long each hand remains underwater.
- Whales, Weddell seals, and penguins all have blubber.
Discuss how the solid shortening is like the blubber that these Antarctic animals have.
- Discuss what other advantages blubber gives marine animals besides warmth. (buoyancy)
- Remove the bags from the students' hands and seal the bags so water won't get in. Attach weights to the outer bag of each "glove."
- Put the bags into the bucket of water. How much weight can each bag hold before it sinks to the bottom of the bucket?
Blubber as a food reserve
Once penguins have laid their egg, the parents take turns incubating it. The parent that stays on the nest keeps the egg warm while the other is off feeding on krill and fish. Adelie penguins trade off every two weeks, while Gentoo penguins switch every day.
How are the Adelie penguins able to survive for so long while sitting on the nest? How are the Gentoo penguins able to find enough food to sustain themselves while remaining relatively close to shore? What strategies for nesting and incubating do other penguins species undertake?
- four large resealable clear plastic bags
- one pound of solid vegetable shortening (such as Crisco)
- duct tape
- a bucket of cold water with ice cubes
- a watch with a second hand or a stop watch
- weights (stones or weights used on a balance)