Topic: Keeping warm in cold water
Method:Students will experience the benefit of having blubber in ice cold water
Time: 10-15 minutes
Age:6 – 12 years old
Background: Surviving in cold water for mammals is a challenge. Being warm-blooded creatures, mammals must keep their body temperatures above freezing. There are a number of adaptations that marine mammals exhibit to survive in the icy waters of Glacier Bay National Park.
Materials: Bucket of icy water, vegetable shortening, gallong plastic bags, heavy tape
To make a Blubber Glove:
Take a large (gallon) plastic bag and put a generous amount of vegetable shortening into this bag. Insert a second bag into the bag with shortening. Tape the top of the bags together. Seal with multiple layers of tape. The shortening can turn into a liquid and leaks through the tape.
Procedure: Discuss how quickly our bodies are chilled in cold water. If we get cold, what can 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 fur, oil on feathers, and low surface area to volume ratio).
Fill the plastic container with ice and some water.
Place the blubber glove on one hand and an empty plastic bag on the second hand.
Place both hands simultaneously into a bucket of cold water.
Have a student time how long each hand remains underwater.
Have children compare and discuss the results. Did the blubber keep the hand warmer?
Extension: Many of the marine mammals we see in Glacier Bay keep warm with a layer of fat we call blubber. But there is one marine mammal living here that doesn’t have blubber to keep warm. That mammal is the sea otter. Sea otters keep warm by a thick layer of fur, which traps air to keep the cold water from its body and sea otters also must eats lots of food to keep their metabolism high which keeps their body temperature warm.
Discuss with the students: Why do marine mammals want to live in cold water environments?
What is the driving force for humpback whales to migrate all the way from Hawaii to Alaska (Glacier Bay NP) to spend the summer? It is the abundance of food.
Last updated: February 15, 2018