If a tree falls in the forest and nobody hears it, does it still make a sound? What’s the sound of one hand clapping? What rhythm does solar energy make when it hits a giant megaphone powered by solar-powered robot percussionists?

These are life’s greatest aural riddles. And a group of artists in Minneapolis is taking inspiration from these big questions to create artworks that explore renewable energy, sound, engineering, human interaction, and possibilities this weekend through September 8th at the Bakken Museum‘s Green Energy Art Garden.

According to LiveGreenTwinCities:

The four sculptures for the Green Energy Art Garden were commissioned specifically for this event by local artists, some working solo, some as a team. Each piece of art has its own way of making the point that renewable resources like the sun, wind, and water can power an exhibit just as exciting as anything plugged into a socket inside the museum proper.

Three local artists have created a solar-powered acoustic sculpture, called the “Sonic Articulation of Sunbeams,” a large-scale megaphone that converts solar power into rhythms and allows visitors to “hear” solar energy. Another sculpture, called “Finite to Infinite,” is a glowing kaleidoscope utilizing bottles, wind power, the sun’s rays, and energy-efficient LEDs. “Make it Rain,” according to Bakken, is “a playful interactive sculpture that invites visitors to experiment with the physical manifestation of the sun’s energy”; and “Solar Spitters” uses solar pumps to spur the spitting of three goblins.

All of the pieces are as interactive and artful as they are educational and inspiring.

“I think an art-based interpretation of science can create curiosity in ways that a purely educational exhibit cannot,” Minneapolis artist and designer Emily Stover tells Highwire. Stover was one of three artists involved in the design and creation of “The Sonic Articulation of Sunbeams.” You can check out a video of the sun’s “sound” here.

“There are incredible scientific processes that happen all of the time,” Stover says of inspiration for the project, “and the first step to harnessing their power is to become aware of them in a fundamental way. Our hope is that our work can shift the way visitors understand the enormous capabilities of our environment, and the technological possibilities of utilizing these resources.”

The opening is tonight (Friday) from 5-8pm. But you can check out all of the pieces, all powered by renewable energy, now through September 8th.