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Playing In The Snow Without A Jacket
The
Importance of Fat as Insulation
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Background
Have you ever been in the snow without a jacket? You find out quickly that
you need the insulation to stay warm.
To demonstrate how fat keeps sea mammals warm, students can test this
for themselves "first-hand".
(Read on and you'll see what we mean.) Try this experiment from Manatee expert
Bob Bonde and Whale expert Ann Smrcina. It may be a bit messy, but the experience
is worth it!
Materials Needed
- Bucket
- Ice and
water
- Rubber
gloves
- Crisco
(vegetable shortening)
- 2 Thermometers
1. Fill
a large bucket with ice water (3/4 full).
2. Fill a plastic bag with Crisco.
3. Put a rubber glove on one hand. Now put that hand into
the Crisco, so the glove is fully covered with Crisco.
4. Submerge both hands — one bare, and the other with
the glove and Crisco — into the bucket of ice water.
- How long
can you keep your unprotected hand in the water?
- How long
does it take before you can feel the cold through the fat-insulated
hand?
- How long
can you keep this hand in the water?
5. Thermometer
Test
- Submerge
one thermometer into ice water and record the temperature of the
water. How long does it take for the thermometer to drop to the temperature
of the ice water?
- Next,
put a thermometer inside the Crisco-covered glove that you
used in the first experiment. Before you submerge the thermometer,
make a prediction of how long you think it will take before
this thermometer registers the same temperature as the ice
water. After you submerge the thermometer, record the temperature
each minute.
National
Science Education Standards
- Objects
have observable properties, including size, weight, shape, color,
temperature, and the ability to react with other substances. Those
properties can be measured using tools, such as rulers, balances,
and thermometers.
- All organisms
must be able to obtain and use resources, grow, reproduce, and maintain
stable internal conditions in a constantly changing external environment.
Special
thanks to Bob Bonde & Cathy Beck, USGS
Sirenia Project
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