Grade 6 students recently discovered that microorganisms act as decomposers in our school compost. We decided to further investigate the role of microorganisms in our environment. We went on a walking field trip to Beus Pond, taking notes on the diverse plant and animal life there (most of which depended on microorganisms for food). We also collected water samples, with the hope of viewing pond microorganisms under the microscope. Unfortunately, we found none. We are currently troubleshooting why this might be.
Meanwhile, we pulled out the laptops and found some movies of microbes commonly found in pond water on the Internet. Students illustrated a few different protists in their science journals, then described how each one moved (using cilia, a flagellum, or pseudopods). Birds at the pond are not the only creatures who eat microorganisms. We looked for microbes in our food and found bacteria in our yogurt! We stained the bacteria with methylene blue to make it easily visible under the scope. (So cool!)
Meanwhile, we pulled out the laptops and found some movies of microbes commonly found in pond water on the Internet. Students illustrated a few different protists in their science journals, then described how each one moved (using cilia, a flagellum, or pseudopods). Birds at the pond are not the only creatures who eat microorganisms. We looked for microbes in our food and found bacteria in our yogurt! We stained the bacteria with methylene blue to make it easily visible under the scope. (So cool!)
Next, students worked in small groups to design an experiment that would test the growth conditions for yeast. Yeast is a fungus used to make bread and other foods. The variables we tested included different food sources (i.e., honey, salt, syrup, and flour). We used the carbon dioxide gas produced by yeast as an indicator of growth. We captured the gas in balloons, comparing the gas produced in each tube relative to the control.
In the experiment shown here, the red balloon is the control and the yellow balloons are the variables. We discovered that yeast can eat anything with sugar (including syrup or honey), but not flour or salt. Students recorded these observations in their science journals. By the way, the lovely smell of the yeast experiment was a nice contrast to the stink of our previous experiment involving the decomposition of a potato.
Now that we have seen how microorganisms can be helpful, it's time to shift gears and study how microorganisms can be harmful.
Now that we have seen how microorganisms can be helpful, it's time to shift gears and study how microorganisms can be harmful.