When it came time to choose a science fair project, partners Camille Sherrill, 12, and Eden Maxwell, 12, looked for inspiration close to home.

Knowing there’s plenty of agriculture and farming in Montana, they decided to measure how different types of fertilizer affect the pH of water that has flowed through it — such as when rain falls on a field and then flows into streams or rivers.

They tested four types of fertilizer: phosphate fertilizer, cow manure, bone meal and fish emulsion.

“Our hypothesis was that the phosphate fertilizer would change the pH the most, and it did,” Sherrill said. Still, they were surprised by their findings. “We thought it would be more alkaline, but it made it more acidic.”

The students poured water over soil in a container, and let the water drain through holes in the bottom. They then measured the pH of the water gathered below.

“Farmers should use not a ton of fertilizer because it can hurt rivers, streams, and lakes,” Maxwell said. “They should use organic forms. Acidic water can harm wildlife, and mess up how the water is.”

Sherrill added that animals adapted to a certain water pH could be harmed by changes in the water’s acidity.

Sherrill and Maxwell worked on their project over lunch, finalizing their conclusions and making suggestions for further study. They’re preparing for the state science fair on March 19. Last year, the Missoula International School won best small junior high at the state fair.

Former student Julian Bain was a national finalist for his science project, a device that made eyeglasses auto-focus by manipulating the shape of the water-based lens from convex to concave. He and his science teacher, Jen Gebo, both had minor planets named after them as a reward.

For the past five years, MIS, with Gebo leading the way, has focused on teaching students Science, Technology, Engineering, Arts and Mathematics. Students learn to use a 3D printer, and have classes in robotics and coding.

The preschool through eighth grade school is an independent nonprofit, which has given school leadership flexibility in implementing new programs. It also offers Spanish immersion and was the first International Baccalaureate World School in the Northern Rockies.

During their lunch, other students also stayed in to work on their projects. They range in topics from water desalinators, to ways to improve solar panel technology, to growing bioluminescent fungi in various environments, to solving the age-old problem of hockey-glove stink.

“They find challenges in the world and come up with a solution for it,” Gebo said.

In the room next door to the science students, another group stayed inside during lunch to solve math problems. They’re preparing for the state Math Counts competition, which also takes place on March 19, in Butte.

This year, five MIS students qualified for state. Math Counts is an after-school enrichment program that teaches students how to solve complicated math problems in algebra, geometry and probability. There are 27 students — more than half of the school’s middle schoolers — in Math Counts.

“They are proof that math can be appreciated and enjoyed beyond competition,” Gebo said.

Emmaline Derry, 13, said she’s excited for the competition, and loves to learn creative ways to solve problems from the Math Counts coach, Michael Curtis. She said she wants to take challenging math courses in high school thanks to her time in Math Counts.

The team recently had a heated debate over whether 0.9 repeating is equal to 1.

“Every day Michael can come, we do problems,” Derry said. “And without him, we do them by ourselves.”

The students have learned to see math problems as more than memorized formulas and linear challenges. “I like the elegance of problems. It might seem simple on the outside but it’s not easy at all, and you have to find a cool way to solve it that's not just math," said McKenna Summers, 12.

The students often stay after school together to solve problems, and sometimes graduates stop by because they miss it. Everyone supports each other, and older students teach the younger kids who are new to the program, they said.

Throughout the school, there’s a big focus on projects and learning through hands-on problem solving, said Jeff Kessler, assistant head of the school. They also have strong female role models in the sciences.

“You see tons of girls doing very well in math and science by the time they’re in middle school," Kessler said. "Hopefully, we’re helping to reverse the trend of girls not choosing STEM fields.”