Willie Hoskins - Williams School
Topics in Environmental Science
Willie Hoskins Williams School
2710 S. Dearborn
CHICAGO IL 60616
(773) 534-9226
Objective(s):
To model the atmosphere of the earth. To build a model to simulate the
greenhouse effect. To use diagrams and models to generate data. To analyze and
interpret data, especially the results of introducing pollutants into nature.
To form scientific hypotheses of how long-term exposure to pollutants will
affect the future of the earth.
Materials Needed:
candles, matches, saucers, dirt, rocks, gravel, small plants, water, lamp,
thermometer
Strategy:
The instructor strikes the match and lights the candle. Each student is asked
what he or she observed. The instructor will hold the bottom of a saucer over
the flame. Then blow out the match and examine the underside of the saucer.
The same procedure will be repeated with burning paper. Discuss what was
observed and conclude that when the yellow part of the flame came in contact
with the cool dish, a black substance as well as moisture was deposited
moisture also was present. Explain to the students that anything can be
called a fuel, and that most fuel contains carbon, hydrogen, or both. When a
carbon containing fuel burns incompletely, it usually glows with a yellow
color and deposits black carbon as was seen on the saucer. When the flame
cools more slowly, the carbon in the fuel joins with oxygen from the air and
forms carbon dioxide (CO2), a colorless gas. The moisture formed on the
saucers, because every flame gives off water vapor. This is because the fuel
contains hydrogen which reacts with oxygen in the air to form water vapor.
Draw and illustrate all levels of the Earth's atmosphere. Take two clear
plastic containers and fill with two centimeters of gravel and one layer of
rocks. Add one and a half inches of soil. Plant plants in the dirt, put a
little water on each new planting, add one more inch of soil, and water until
soil is soaked. Place a thermometer in the soil and be sure the bulb is
submerged in the soil and the end is resting on the wall of the container with
the number clearly visible through wall or top of container. Cover one of the
containers with plastic or plastic wrap. Check the thermometer in both
containers after 40 minutes. Discuss and record data and conclude that the
temperature increased in the covered container.
Performance Assessment:
Students should observe the changes in the atmosphere and the soil temperature
inside the container at different times compared with the atmosphere and
temperature of the room.
They should also compare the model greenhouse and the illustration of Nature's
Greenhouse. What happens at different temperatures? What happens during
photosynthesis?
Conclusions:
Incomplete combustion of fuels can lead to the production of soot. Heat
trapped by the cover of an artificial environment increases the temperature of
that environment just as thought it happens in the greenhouse effect on
Earth.
References:
Navarra, J. G. and Zafforoni, J., Today's Basic Science, Harper and Row, New
York (1971), pp. 38-47.
Understanding the Greenhouse Effect, Ward's Natural Science, P.O. Box 92912,
Rochester, NY 14692 (1989).
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