Error and Analysis

While our experiment was successful, we had one major issue that may have skewed the results. The elodea has been filtering the acidity out of water, so the pH was expected to increase over time. The pH was steadily increasing by 0.1 every day but, unfortunately, some of our test tubes grew mold. We think the mold in the tubes grew because the test tubes were openly exposed to the air for a long period of time. In the future, we should try to work on making sure the test tubes are fully covered. We should also use a test tube stopper to block the airways which will prevent mold issues in the future. Through this error we discovered that the moldy test tubes had a lower pH then they started with.