Silver Spring ninth-grader Katherine Wu placed second at the Young Scientist Challenge — one of two science competitions in which she is participating this month. (Andy King/Discovery Education 3M Young Scientist Challenge)

The most important thing Jai Kumar learned from participating in the Young Scientist Challenge? How to fail.

“I failed many times,” he said. “Building stuff, testing stuff, researching stuff.”

Jai’s biggest failure came a few weeks before the competition finals. The seventh-grader at J. Michael Lunsford Middle School in Chantilly had been working on a water-powered air filter inspired by a visit to his grandparents’ home in India, where pollution often keeps people from opening their windows. But when he learned that many people in India and other poor countries don’t always have access to the water needed for his filter, Jai (pronounced “Jay”) decided to revamp his project.

“The good thing about failure is that you can build off of it to come up with another failure, and another one, until finally you get to a success,” Jai said. “And when you get there, you know you’ve got the best solution, because you’ve tried so many other ones.”

At Young Scientist finals last weekend in St. Paul, Minnesota, Sahil Doshi of Pittsburgh, Pennsylvania, took first place with an eco-friendly battery. But Jai’s Ultratitan, which uses ultraviolet light rather than water to remove dirt and toxic gases from the air, came in third out of 10 finalists.

Chantilly middle-schooler Jai Kumar took third place at the Young Scientist Challenge with his "Ultratitan," an air filter that uses UV light to keep out pollution. (Andy King/Discovery Education 3M Young Scientist Challenge )

Jai is not the only local student to wow the judges at the yearly science competition, which is held by Discovery Education and the technology company 3M and which challenges middle-schoolers to invent solutions for problems affecting their communities or the whole world.

Katherine Wu, a ninth-grader at Montgomery Blair High School in Silver Spring, took second place.

Much like Jai’s, Katherine’s invention was inspired by her family. After noticing that her parents often got drowsy during long road trips, she invented “the driver’s companion,” a device that could monitor drivers’ blinks and brain waves to see if they were in danger of falling asleep at the wheel.

Jai, Katherine and Ana Humphrey of Alexandria were selected as finalists at the beginning of the summer. Helped by mentors who work at 3M, they had about four months to develop a prototype, or model, of their invention in time for the finals.

Both Jai and Katherine said it was a long road from their original idea to a finished product.

“Even though I knew the general process, I never expected how long it would take,” Katherine said.

For example, once Katherine knew she wanted to prevent drowsy driving, she had to study neuroscience to find out how to identify signs of sleepiness, take an online course to learn how to create the computer code that would recognize those signs, build the device and test it on volunteers.

But Katherine is putting all that hard work to good use: This week she is competing in another national science competition, the Broadcom MASTERS, which runs through October 29.

Even once the contests are over, she and Jai plan to keep working on their projects, possibly developing them into an actual product. And maybe someday, Katherine’s parents will wear her device during their drive down to Florida.

But not quite yet. “I have to do more testing first,” Katherine said.

Sarah Kaplan