Staying Warm in the Ocean:
Exploring Whales' Physical Adaptations
Whales, and especially right whales, have a very low surface
area to volume ratio. The right whale has a particular shape - a torpedo-like
body shape and reduced limbs. Over time this shape evolved into a large
volume body with the least amount of exposed external appendages. Natural
selection decreased the amount of surface area exposed to the external
environment while increasing volume. Right whale adaptations include: a
heavy, round body; short, stubby limbs; no dorsal fin; and a thick layer
In this lesson, students predict and observe how water temperature can
affect body temperature, depending on the shape and insulation of the body.
In Your Classroom
Look at a picture of a right whale. Describe its anatomy--the shape and size
of its body, limbs, fins, etc. Have students brainstorm why they think the
right whale has adapted to that shape?
Materials You Will Need
- hot and cold tap water
- a dishpan or bucket
- a thermometer
- 2 zip-lock sandwich bags
- 1 styrofoam cup
- 1 disposable plastic glove
- Fill the dishpan or bucket half full with cold
water. This will be your "ocean."
- Measure equal amounts of hot water for both sandwich bags and
the glove. Tie or tape the glove to prevent leaks.
- Take the temperature of the hot and cold water and record.
Both bags and the glove should begin at the same temperature.
- Place one of the bags of hot water inside a styrofoam cup and
fold the top down around it to seal in the bag. Tape closed if
- Place all three into the dishpan of cold water. Leave them
in for five minutes.
- While the students are waiting, have them predict what will
happen. They should predict how the temperature of each of the
three objects will change, and explain why.
- After five minutes, remove the glove, the plain bag and the
bag in the styrofoam cup. Take the bag out of the styrofoam cup.
Take the temperature of the water inside each of the three objects.
Compare these temperatures to those taken before submersion.
Evaluate Your Results
- After five minutes in the cold "ocean" water,
which was the warmest, the coldest? Did it make a difference
one bag into a styrofoam cup? Were your predictions accurate?
- Describe how each of the three items is similar or different
from a whale's body.
- Why do you think we used a glove? (The glove is like an animal
with long legs. It has a lot of surface area in relationship
to its volume.)
- The styrofoam represents part of the anatomy of a whale. Which
- How is a plain sandwich bag like a whale's body?
- Brainstorm a list of mammals that live in the sea. How many
of them have long legs? Where in the world's oceans do they live
(arctic, temperate, tropic, coastal or open ocean)?
- How does surface area and volume of an object affect its heat