Destruction of the Rainforest and Atmospheric Oxygen
Pre-service Middle Childhood teachers in the Earth Systems class tried to devise a laboratory activity to test the assertion that destruction of the Brazilian Rainforest would lead to a decrease in the oxygen levels in the Earth's atmosphere. They were to collect data, analyze the results and use their results to determine if the assertion was true based on their experiment.
Learn more about the course for which this activity was developed.
- To provide conceptual understandings in Earth System science and to develop student understanding and application of these science concepts in a variety of real-life situations.
- To develop student understanding and application of science process, problem-solving, and critical analysis skills.
- To strengthen student mathematical skills and understanding through integration of mathematics with science activities.
- To develop student abilities to utilize multiple representations while organizing and solving problems.
- To develop student understanding of national and state science standards and scientific literacy.
- To develop student understanding of the impact of attitudes about science and science learning.
Context for Use
Description and Teaching Materials
The students studying the impact of the destruction of the Brazilian Rainforest on the Atmosphere had completed their group research and had finalized the writing of their interactions. One of their interactions was that the destruction of the rainforest flora would lead to a decrease of atmospheric oxygen. When pressed to further explain their position they stated that it was self-evident. Plants produced oxygen- less plants, less oxygen. This led to a lively debate between those students who thought that the loss would be so small it would be imperceptible, and those that thought the impact would lead to a serious decrease in atmospheric oxygen. The students decided that they would develop a laboratory exercise to settle the issue. The first attempt was to create small pop-bottle terraria with a few plants and others with many plants, then test the concentration of oxygen in each terrarium. After the experiment had begun the students decided that it would be impossible to test for the concentration of oxygen in the atmosphere in each bottle, because they didn't have the equipment needed to do so.
Then they decided that they could easily test the concentration of oxygen in water so they devised a more elaborate experiment. Each group would fill three Mason jars with water and place a few sprigs of Elodea (an aquarium plant) in one of the jars and triple the amount of Elodea in another jar. The third jar contained no Elodea at all and was to be used as a control. They would wait a week and then use a Hach Water Oxygen Test kit to determine the oxygen levels in the water in each of the Mason jars. When they opened the jars a week later, much to their surprise, all the plants were dead and there was no discernable oxygen in any of the jars, even the control. The lids of the jars had rusted. The experiment was an abject failure on one level but taught them volumes about how rusting occurs, if plants use oxygen in photosynthesis, and that sometimes more learning comes from failure than from success.
Teaching materials-Pop bottles, Mason jars, Elodea plants, Hach Water Oxygen Test Kits
Teaching Notes and Tips
References and Resources
Slattery, W., R. Teed, T. Cole (2007). Earth Systems: A Multi-Disciplinary Course Designed for Pre-Service Middle School Teachers. Journal of Geoscience Education 55(3), 218-221.