From Sandbox to Soundwaves: How Summit School’s Henry Heidtmann Built a Platform for Student Voices

On his very first day of kindergarten, Rich Boerner was inconsolable. He clung to his mother’s leg, sobbing, unwilling to stay behind when she tried to leave. His teacher walked him out to the playground, where another boy, Henry Heidtmann, sat in the sandbox with a collection of toy cars.

“Want to play? You can have this one,” Henry said, offering Rich a little green dump truck.

Rich looked at the toy, stopped crying, and joined him. It was the beginning of a great kindergarten day—and a lifelong friendship.

Years later, Henry had become the go-to “AV guy” and Classroom Technology Specialist at Summit School, a founding member of NCAIS. There, he launched a student radio station, giving middle schoolers hands-on experience with microphones, mixing equipment, and the art of storytelling. Students created segments on everything from making grandma’s cookies to debating the best pizza toppings.

The transformation was striking. Quiet students who rarely spoke up in class lit up behind the microphone. They grew more comfortable with their voices, more confident in their ideas, and more willing to take risks.

The radio station eventually evolved into a podcasting program. Teachers began to notice how much students enjoyed the format—so much, in fact, that other faculty members started using it as an assessment tool. A book report could become a podcast segment. A language learning project could turn into a recorded conversation. What began as an enrichment activity became an innovative way to evaluate and inspire digital-native learners.

Henry was amazed. His students weren’t just producing audio; they were owning their voices. But how could their work reach beyond the classroom without compromising student privacy? For years, that question kept the program contained within the school walls.
 
The answer arrived through an old friend.

At a reunion, Henry reconnected with Rich—the same boy who had once been comforted by a green dump truck on his first day of kindergarten. By now, Rich was a father of three and working at a radio station in California. They swapped stories about their careers and realized they shared a passion: helping the next generation develop strong communication skills.

Together, they founded DumpTruck Media and its signature project: The SandBox Network Podcasting Program for Grades 4–9.

Designed as a safe, private podcasting network, The SandBox Network allows only participating schools to share and hear content. Teachers manage all uploads, and students use only their first name and school name for identification. The program blends a flexible curriculum with space for creativity, giving students both structure and freedom to find their voices.

“We want kids to have a voice,” Henry explains. “And we want them to hear each other’s voices—not just in their classrooms, but across schools and communities.”
 
What started with a single toy truck in a kindergarten sandbox has grown into a platform amplifying student voices in independent schools nationwide. And just like that first day of school, Henry and Rich are still helping each other—and countless young learners—discover the power of communication and connection.