Mia Heller, 18, heard that the tap water in her town of Warrenton, Virginia, was full of microplastics. So she designed a filtration system that uses ferrofluid, a magnetic oil that binds to microplastics, to pull up to 96 percent of the tiny plastic particles out of drinking water. Her project made her a finalist in the Regeneron International Science and Engineering Fair. The system is currently just for home use, but she hopes to keep developing it.

Q: Did you have experience with this kind of science already?

A: Not really. I learned a lot of things on the go. But I did have an interest in architecture beforehand, and I think being able to visualize things was my biggest asset going in.

Q: You designed this whole project at home, right?

A: Yes, I didn’t have access to laboratory equipment. I needed something that I could design and build using what I had at home. So I developed sensors and things like that to test with.

Q: Any advice for teens working on their own science projects?

A: Failures happen for a reason. Sit with them. Think Why is this happening? What can I learn? Using them as a learning experience is going to make you more skilled.

This interview was edited and condensed for length and clarity.