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Revised: Jan. 22. 2002
EXPERIMENT 4:
HEAT AND INSULATION
Introduction
The purpose of insulating materials is to impede the flow of heat from
inside a container (a bottle, a Thermos jug, or a house) to the outside;
or to impede the flow of heat into a container from outside (e.g., a Thermos
jug filled with cold lemonade on a hot Summer day). In this experiment,
we explore the effect of various insulating materials on the heat loss
from a bottle filled with warn water.
Equipment needed
two 2-liter soda bottles with caps
two thermometers or temperature probe
10 in. x15 in. blanket material and other flexible material (sheets
of paper, cloth, aluminum foil, etc.)
duct tape or masking tape to fasten the insulating material to the bottle
Procedure
Make holes in bottle caps to run the temperature sensors through; fill
both bottles with very warm water to the same height (use about 1.5 liters
in each); screw on caps with sensors through them. Plug up the holes in
the caps with clay or Play-Doh to seal.
Wrap one bottle with one of the insulating materials and hold in place
with tape.
Record the time and temperatures in both bottles immediately and then
periodically thereafter (probably every 5 minutes will be enough) until
the uncovered bottle reaches room temperature
By repeating with other covering materials, students will be able to
observe the effectiveness of insulation over no insulation, and the relative
effectiveness of various insulating materials.
(It would be interesting to wrap the bottle with aluminum foil only,
and then with foil covered by one of the other materials, measuring the
temperature loss in both cases. Making this set of measurements will determine
the value—if any—of having an underlayment of aluminum foil.)
These experiments could be a good prelude to the “Keeping the Heat”
experiment, both in developing technique and in identifying good and poor
insulating materials.
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