Garrett Neese/Daily Mining Gazette Mind Trekkers volunteer Sierra Williams watches Juliette Piret, 6, and Maxi Piret, 6, of Houghton, play music using green bananas in a demonstration of electrical circuits during the Mind Trekkers’ STEM Open House at the Carnegie Museum of the Keweenaw. By holding the lime, the musician becomes part of the circuit, which they complete by hitting a banana, connected via cables to a circuit board, which translates the contact with the banana to a musical note.

HOUGHTON — At the Carnegie Museum of the Keweenaw Saturday, children built stable bridges, watched chemical reactions unfold and turned fruit into music.

It happened at the Mind Trekkers’ STEM Open House, where the Michigan Technological University group taught children about science, technology, engineering and mathematics through hands-on demonstrations that sent kids and parents moving between both floors of the museum to catch everything.

The group does the events a few times a semester, vice president Kira Shaffer said, pausing to greet a child who high-fived her with gloves inflated by carbon dioxide. Those range from running local activities to taking part in larger-scale STEM programs in places like South Carolina.

Shaffer has loved working with the Carnegie and getting to connect with the local community.

“Getting younger students involved in STEM activities or getting to know more about STEM is very important,” she said. “So I think that’s my favorite part of that, is being able to contribute that into a community. But I also just really enjoy seeing kids get really excited about things, or something new they didn’t know existed.”

For each event, Mind Trekkers picks demonstrations from a collection of more than 200, housed in three storage units.

“The nice thing is, we have so much to choose from, so we get to pick what we want to do, and what we like to do,” Shaffer said.

In a confined space in close proximity to historical artifacts, that rules out the fire demos. Same with the liquid nitrogen explosions.

But the museum setting did tie in with other exhibits, where children learned how to build beam or suspension bridges, and the principles underlying them. Placards explaining them also showed photos of examples the kids might have seen in real life, such as the Eli Avenue Bridge, a beam bridge in Gogebic County.

Downstairs, 6-year-old twins Maxi Piret and Juliette Piret of Houghton were enjoying the Musical Fruit table. A series of green bananas were hooked up to a MaKey MaKey circuit board, which is then plugged into a computer. By holding onto a lime at the same time, the musicians use their natural electrical conductivity to complete the circuit.

With those connections complete, tapping the bananas triggers an online keyboard. Guides at the table showed which bananas to hit to play simple tunes like “The Itsy-Bitsy Spider.”

The kids were excited to learn about science, said their mother, Cécile Piret. Maxi wants to learn how to make magical potions, “which is a little bit like chemistry.”

“It’s wonderful, super-interesting,” she said. “They even took their notebooks to take notes if they were interested in something.”

Their favorite activity had been the carbon dioxide gloves, which they carried with them.

Juliette’s favorite part was “that it got colder.”

That comes from the heat released through the exothermic reaction that occurs when acidic vinegar reacts with baking soda, a base. One of the products is carbon dioxide, which filled the gloves carried by Nagi Nakamura, 8, of Chassell.

What did he like about coming there? “Everything,” he said.

“He likes science experiments, and he came here last year too, and he enjoyed it a lot,” said Nagi’s mother, Asako Nakamura.

The day fits in with the Carnegie’s concept of a community museum, which draws people in through rotating exhibits and programs, said Elise Nelson, the museum’s director.

When the Carnegie opened, it had a similar event — Science Saturdays, modeled after Tech’s science fair.

The museum staff put it on themselves.

“And it was exhausting,” Nelson said.

So the museum began working with the Mind Trekkers, who did events once or twice a year pre-COVID; they had their first event back last year. For the first time Saturday, the events expanded to both floors.

She sees Saturday’s event as a great marriage between Tech and the community. Though the Mind Trekkers travel all over, when they host events locally, “it’s like having a mini-science museum in town,” Nelson said. And having it at the Carnegie brings in families who might be too intimidated to attend an event at Tech itself, she said.

“I think this is a great venue to bring the larger community together in one place,” she said. “I think it’s a great way for students to be able to come and teach and interact with kids.”

The Carnegie will hold its Holiday Open House from 1 to 3 p.m. Dec. 14, which will include gingerbread house decorating, holiday music, hot chocolate and other treats.

Mind Trekkers’ next event is the third annual OneUP Copper Trail Festival, a STEM and career expo with hands-on demonstrations for about 800 sixth-grade students. Presented with UP Michigan Works!, the MiSTEM Network and the OneUP Collaborative, it will be held Dec. 10 at Michigan Tech. Other upcoming events will take them to Port Huron and Green Bay.