Grade Level: 1st to 8th grade

Objectives
Students will learn about the importance of insulation in keeping warm.
Students will understand how blubber keeps marine mammals warm in the ocean.

Background Information
Marine mammals are warm blooded. On average a whale's body temperature is a couple degrees more then humans (98.6° F) but varies with each whale species. Heat loss is much greater in water than in air. Insulation prevents the passage of heat out of a body. Humans are insulated by fat with the help of clothing and shelter. Whales and dolphins however spend all of their lives in the water are unable to conserve body heat by curling up, seeking shelter in a protected place, or putting on coats like humans. Whales rely only on a dense layer of connective tissue with fat called blubber. It acts as their insulator, to conserve body heat. Blubber thickness can vary from a couple of inches in smaller whales and dolphins, to over a foot thick in the right and bowhead whales.

Materials
Ice and water
Dishpans
Rubber gloves that are too big for the students
Gloves made of assorted materials - rubber, cotton, wool, neoprene diving glove
Stop watches or clock with a second hand
Thermometers
Blubber bags
Crisco©
Quart or pint size Ziplock© bags
Tablespoon
Paper towel
Packing tape

Making Blubber Bags
Put half a can or more of Crisco© in a Ziplock© bag. Take another bag and turn it inside out. Put this bag in the bag of Crisco©. Push it down gently so that the top of the bag on both bags matches up. Keep the Crisco© pushed a couple inches from the ziplocks. Carefully lock the two bags together. Wipe the top of the bags clean with paper towel. Fold a piece of packing tape over the top of the two joined bags and press it down tight. You now have a Blubber bag. Blubber bags can be their own experiment too. Using a hand dipped in water without a bag as the control; students can compare the insulation effectiveness of Blubber bags that have been made with different amounts of Crisco©.

Procedure
1. Discuss body heat and insulation. Divide the class into small groups of 3 - 4 students. Depending on the grade level, have enough materials for each group to simultaneously do the activity or do the activity with student helpers as a demonstration.

2. See example observation sheet for the students or have them design their own sheet.

3. Fill the dishpans with ice water.

4. Ask the students to predict what the temperature of the ice water might be. Then have them take the temperature of the ice water. The temperature of the North Pacific Ocean varies from 48-64°F. Is the water within the temperature range of the North Pacific Ocean? If not try to add more water or ice so that it is.

5. To demonstrate the effectiveness of insulation as a protection from cold water students will take turns (or all at once if you are using a clock where they can keep their own time) putting a hand in the ice water without gloves (control). Next have students use a rubber glove only, a rubber glove lined with other gloves (cotton, wool), blubber bags and a scuba glove (if available). See how long they can keep their hand in the water. Important: Students should be serious about this and not thinking of this activity as an endurance test or to be the one in the group that can do it the longest. Stress that they need to think of their hand as their whole body. So as soon as it becomes chilled they pull their hand out and stop timing. Record results on the observation sheet.

6. Compare the results. Which hand covering provides the most warmth?

More Discussion
What do humans do to warm up if we are cold? (shiver, blow in our hands, turn up the heat, put our hands in warm spots like under our arms or between our legs, cover up with layers) When humans stay in the water for long periods of time what do we need? (wet suits, dry suits, a submarine with a controlled temperature). A human being without any protection in water that is 32°F or 0°C can loose consciousness in ten minutes.

Pinnipeds and polar bears have both blubber and fur to help them conserve body heat. Sea otters do not have blubber they rely only on their thick fur. The fur traps air that serves as the insulator keeping the water from soaking through to the skin.

Sample Blubber Worksheet