Marcus High School students formed a nonprofit chapter that teaches hands-on science to elementary-age kids in Flower Mound. Their first library event sold out within days.

The Marcus STEMsters, a student-run chapter of the national STEMsters 501(c) nonprofit, came together toward the end of the 2025-26 school year. The group pairs high schoolers with children in kindergarten through fifth grade for projects built around physics and engineering concepts, the Cross Timbers Gazette first reported Friday.

The chapter's first public session, a "Marshmallow Catapult" event at the Flower Mound Public Library, filled up days after it was posted, according to the Gazette. Participants built marshmallow catapults while learning the basics of kinetic and potential energy.

The group's next session is set for Sunday, Sept. 13, from 2 to 3 p.m. at the Flower Mound Public Library, 3030 Broadmoor Lane. That session focuses on air resistance, drag and paper airplanes for children in kindergarten through fifth grade.

Ruhika Aleti, the chapter's president, told the Gazette the group fills a gap she noticed in her own childhood.

"We didn't really have something like this growing up, so being able to help the younger generation explore this and figure out what they're interested in is great," Aleti said.

Vice President Anjali Bose told the Gazette the hands-on format lets students go further than a typical classroom setting. She added that the teen volunteers are passionate about the subjects they teach and enjoy watching younger kids engage with the material.

PR Manager Mahi Jain told the Gazette that one highlight has been watching older kids step into leadership roles and help younger participants during events.

Beyond the library, the Marcus STEMsters plan to bring sessions to local daycares and education centers. No dates have been announced.

Past and planned projects include slingshots, catapults and zoetropes, a pre-film animation device.

The Marcus chapter is one of 11 STEMsters chapters in Texas, according to the Gazette. The organization's website lists more than 82 high school chapters across the country. Amie Bui, the national fundraising director and a student at Silver Creek High School in California, told the Gazette the student-led model sets the group apart.

Members can earn volunteer hours through their work with the organization. Residents can follow the chapter on Instagram at @marcus_stemsters for updates on upcoming events.