Just beyond the typical sixth-grade science class commotion, two other sounds operate in the background of Chad Uhde’s classroom at Bettendorf Middle School: the humming of air pumps and the bubbling of water.

The room is filled with small hydroponic systems that were researched, designed and built by students. The students planted tomatoes, lettuce and bell peppers, and sprouts of plants are beginning to show.

In the spring, Uhde said, the students hope to transplant their vegetables into a greenhouse made of empty 2-liter soda bottles that they built behind the school.

Uhde said he and Kevin Roling’s sixth-grade science students took on the initiative as part of the school’s emphasis on project-based learning. It gives students a task and requires them to learn through their own independent research and trial-and-error rather than being lectured, or corrected, by a teacher.

“It’s hard to stop myself sometimes and not give them an answer,” Uhde said.

The students are more engaged in the subject matter when they have a personal stake in the lesson, he said.

Hydroponics is the science of growing plants in water rather than soil. One group of students constructed an aquaponic system, which combines hydroponics with the raising of marine life. The system includes fish that live in the water, with the fish excrement providing nutrients to the plants.

Uhde said he has been impressed with the amount of research and planning his students have done in creating the systems.

“It’s pretty neat to see how creative they can be when you give them the materials and just let them go.”

Student Maddie Kussatz said the hydroponics project is part of a lesson that includes two other classes — social studies and art. In social studies, students learned about the Hanging Gardens of Babylon, built about 600 B.C. under the rule of King Nebuchadnezzar II and considered one of the seven wonders of the ancient world.

Kussatz said students created a pop-up book in art class about what the Hanging Gardens of Babylon might have looked like.

Student Daniel Wilkinson said the project has been interesting as they researched and experimented with different designs.