If 18-year-old Seth Flaxman had to describe his bedroom in one word, he would use cluttered.

But unlike most teenagers, Flaxman can defend his messy living space in the name of science.

Last summer the Evanston Township High School senior converted his bedroom into a mini-laboratory to create a physics project that has now placed him among America’s top aspiring scientists.

Flaxman is one of 300 students nationwide to have earned semifinalist status in the Intel Science Talent Search, a scholarship competition often called the junior Nobel Prize.

“I investigated heat conduction in a body subject to an oscillating heat source,” said Flaxman of his year-long research project, which included a paper and an experimental model.

And for the non-science minded: “I moved something that was hot back and forth over a copper plate and took temperature readings,” he said.

Such an elementary explanation might remind Flaxman of his many grade school science experiments, but this project has a much larger payoff than the certificate he won in the kindergarten science fair.

As a semi-finalist, Flaxman secured $1,000 for his school and an equal amount for himself. Although he has been accepted to Harvard University, Flaxman doesn’t know how he will use the money.

Flaxman is also unsure what career path will win his interest. His current interests, however, extend past test tubes and Bunsen burners. Despite Flaxman’s fascination with physics, he doesn’t spend all his time in the lab.

“He’s one of the top students I’ve ever taught, plain and simple,” said Flaxman’s physics teacher, Mark Vondracek. “But he wants to come across as just an average guy. It’s not all school all the time. He wants to have some fun, too.”

Flaxman’s fun includes his Jewish youth group and his music — he plays clarinet and tenor sax. He also tutors elementary schoolers in math through a Northwestern-affiliated program called Project EXCITE.

“At least this year, I’ve been really busy,” Flaxman said. “I have all these things that I want to do, but there are so many conflicts.”

In spite of his busy schedule, Flaxman has found time to excel in this highly acclaimed science competition, following an example set by his two older brothers and his father, who also entered the contest.

The Science Talent Search has been awarding scholarships to science savvy seniors since 1942. A panel of some of the nation’s top scientists reviews each applicant’s original science research project.

The application total reached a record high this year with more than 1,600 students submitting entries, according to Science Service spokesman Clint Tanner.

Although Flaxman discovered last week that he did not advance to be one of the Science Search’s 40 finalists, his family just as proud of his achievement.

“He did better on his Intel than I did on mine, many years ago,” said his father, Ken Flaxman.

Earlier this year the youngest of the Flaxman clan also was named semifinalist in the Siemens Westinghouse Competition, a contest similar to the Science Talent Search.

But to those who know Flaxman, none of this has been a surprise.

“He’s always winning some kind of contest, or being some kind of valedictorian, or getting into some kind of Harvard,” said friend and fellow ETHS senior Ezra Furman. “We always tease him about being a nerd. I expect this article to have ‘nerd’ in it at least 10 times.”