Science Buddies: "Ask an Expert"

Hi! For my physical science class this year, we are conducting research projects where we perform an experiment related to any branch of science and create a paper representing approximately 60 hours of preparation. For my experiment, I was interested in the effects of different pollutants on water quality. I'm not sure what my independent variable should be. One idea I had is using different amounts of fertilizer and measuring the water quality. What pollutants of water could I test that are affordable and convenient? I think, for my dependent variable, I want to measure the amount of nutrients such as nitrates and phosphates that are in the water because those are related to eutrophication. Do you have any advice on how to make this experiment more challenging and how to elaborate it further? Thank you!

Hi saanvi!

Your independent variable (what you are changing) in this case would be the type/amount of pollutant you are putting into the water, and your dependent variable would be the amount of nitrates and phosphates. I think that this is a great idea! One of the worst pollutants in water comes in the form runoff. Pollutants found in runoff include fertilizer, pesticides, petroleum by-products and other contaminants. I think that instead of changing the amount of fertilizer, changing the type of fertilizer would make this a more in-depth project. We already know that as the number of fertilizer increases, the amount of nitrates in the water will increase. Testing other types of pollutants would make this a more challenging project.

P.S If you really want to make it more complicated, you could test the effects of algae on cleaning the polluted water (or see eutrophication happen in real life), or test the effects of the polluted water on water flies, called Daphnia Magna.

Hope this helps! - Probiotics

Thank you so much for responding so quickly and for the advice on my independent variable! My mom mentioned using different fertilizers also so I will definitely do that. I have one question. What sources would you recommend for research? I'm not very experienced at this yet. Thanks!

Here is a link from our page on finding research for your project!
https://www.sciencebuddies.org/science- ... arch-paper
Let us know if you have any more questions!