Printer Friendly
Activity: Insulation in Marine Mammals
NGSS Science and Engineering Practices
NGSS Disciplinary Core Ideas


  • Table 6.3
  • Water
  • Ice
  • Two buckets or other large liquid container
  • Vegetable shortening (e.g., Crisco)
  • Bubble wrap
  • Laboratory or exam gloves
  • Two quart-sized plastic food storage bags
  • Stopwatch
  • Long metal probe thermometers or other temperature sensors
  • Masking tape (optional)
  • Computer (optional)
  • Towels


  1. Fill one bucket halfway with ice. Add water until the bucket is mostly filled, leaving approximately 10 centimeters (cm) of space from the water level to the upper rim of the bucket.
  2. Fill one bucket halfway with room temperature or lukewarm water.
  3. Each student will rotate through three different roles as time allows: technician, researcher, and data recorder.
    1. Technicians will prepare activity materials for the researcher.
    2. Researchers will conduct the actual experiment as a test subject.
    3. Data recorder will measure and record data from the experiment and assist the technician.
  4. Researcher
    1. Put on one exam glove over one hand
    2. Gently insert the metal probe thermometer into the cuff of the glove and down the palm-side of your hand. The tip of the thermometer should be near the middle knuckle of your middle finger. Be sure to keep your fingers straight throughout this experiment.
  5. Technician
    1. Label two plastic sandwich bags as “Bag #1” and “Bag #2”
    2. Place Bag #1 over the researcher’s gloved hand
    3. Place Bag #2 over Bag #1 on the researcher’s gloved hand
    4. This combination of exam glove + Bag #1 + Bag #2 will serve as the “bare” experimental treatment and represent a mammal without blubber or dense fur.
  6. Data recorder
    1. Record the temperature reading from the thermometer.
    2. As soon as the researcher’s hand becomes submerged in the water, begin the stopwatch.
    3. Repeatedly record temperature readings from the thermometer every ten seconds.
  7. Researcher
    1. Submerge the gloved hand into the bucket of ice water up to your wrist level. Do not allow water to flow into the glove or bags.
    2. Keep the gloved hand submerged for 90 seconds or until the thermometer reads 15.0 °C. Remove your hand from the ice water earlier if you feel pain.
    3. After removing your hand from the ice water, slowly submerge it wrist-deep into the lukewarm water bucket.
    4. Allow the thermometer temperature to return to within 2 °C of the previous starting temperature before moving on to the next step.
  8. Technician
    1. Prepare the following experimental treatments using bubble wrap and vegetable shortening as follows:
      1. Prepare the “fur” experimental treatment by having the researcher wear the exam glove, then Bag #1 over it. Then apply a layer of bubble wrap around Bag #1 and cover with Bag #2. The researcher should be wearing the glove + Bag #1 + bubble wrap + Bag #2.
      2. Prepare the “blubber” experimental treatment by having the researcher wear the exam glove. Slather a generous layer of vegetable shortening on the outside of the exam glove, then cover with Bag #1, then Bag #2. The researcher should be wearing the glove + vegetable shortening + Bag #1 + Bag #2.
      3. Prepare the combined “blubber” + “fur” treatment by removing Bag #2 from the previous “blubber” treatment. Apply a layer of bubble wrap around Bag #1, then cover with Bag #2. The researcher should be wearing the glove + vegetable shortening + Bag #1 + bubble wrap + Bag #2.
    2. Repeat steps 6 and 7 for each of these experimental treatments.
  9. Record all data in Table 6.3. Repeat experiments for all group members in all roles.
  10. Using graph paper or computer software, plot your data onto a single line graph showing how the thermometer temperature changed over time with each experimental treatment.


Activity Questions
  1. Examine your findings in Table 6.3 and your plotted line graph. Describe some overall trends you observe. Which treatment produced the coldest temperature in the shortest period of time?
  2. How did the bubble wrap simulate fur in marine mammals?
  3. Estimate the temperature of the ice water. Use a thermometer to record the actual temperature. Sea surface temperatures in the north Pacific ocean basin can range from 4 to 12 °C year round. How does the temperature of the bucket of ice water compare to that of the north Pacific?
  4. Most marine mammals have thick layers of blubber. How might this blubber serve as an adaptation to increase a species’ chances of survival?
  5. Pinnipeds and the polar bear have thick fur in addition to their blubber and fat. The polar bear is so well insulated that it cannot be seen by heat-imaging thermal cameras. How might fur serve to keep these marine mammals warm?
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.