How would you tackle the problem of light pollution? If you're a student in Eric Balak's gifted classes at Bear Creek School in the Elizabethtown Area School District, you have an answer to that question.

Three teams of third- and fourth-graders participated in the Pennsylvania Invention Convention earlier this year, and each team earned a spot in the state competition happening on Feb. 7.

The Light Savers, a fourth-grade team comprising Marley Leggett, Timothy Leaman and Zachary Reever, drew inspiration from a lesson on light pollution in their English Language Arts class. Their invention, the "Light Cocoon," features flaps attached to a servomotor that can open and close around a streetlight, directing light downward versus into the sky.

The Plate Pioneers, a third-grade team consisting of Poppy Sands, Kyle Southard, Jacob Pierdon and Charlotte Rosborough, revolutionized the standard school food tray with their creation, "Smart Tray." The tray incorporates color coding, labeling and sensor pressures with LED lights to promote healthier eating habits at school.

Recyclified, another third-grade team composed of Liesel Keller and Fianna Clark, devised a solution to promote and gamify recycling practices at school. Their invention involves a circuit button per grade level, adding a point on a connected scoreboard every time the button is pressed.

For the competition, the teams created a prototype to address a real-world problem of their choosing, kept an invention log and crafted a pitch video for the judges. The students compete on Feb. 7 at the Hershey Lodge with others from across the state, and one team from that competition will progress to the national level.

Balak, who is in his first year teaching at Bear Creek, pitched the idea of competing in the Invention Convention to all 47 of his students. The nine students who chose to participate formed their own teams and brainstormed their inventions together.

"We noticed that when the trash bins were in the hallway in the morning after breakfast, they were really full, and we wanted to make them go down," said Liesel, a member of the Recyclified team. "We also noticed that the milk cartons said 'Please recycle' on them, and they were being thrown in the trash every day. We wanted to change that."

The Plate Pioneers also wanted to solve a problem at school, said team member Charlotte. "We looked at the trays and we wondered, 'Are kids getting a healthy meal?'" she explained. "We came up with our smart tray and we also color-coded the food bar, so kids know which item to match on the tray."

Balak said he was feeling confident about the projects going into the competition, but he was pleasantly surprised when all three teams qualified for the state event.

At the state competition, the teams will present their ideas in person, so they've been working on a one-minute elevator pitch, Balak said.

"We've been preparing by watching some 'Shark Tank' videos," he said.

No matter how the state competition goes, the kids all enjoyed creating their inventions. "I liked building the actual product," Charlotte said. "I also liked doing research on it."

Added Liesel, "The hardest part was figuring out what our invention was going to be. Our original idea was to solve climate change, but that was too big. But, in the long run, our invention is about recycling, so that will help with climate change."