The competition sponsored by Discovery Communications announced that 8th-grader Tyler Yamada of Kula was among the 400 middle school students selected from 44 states.

With a focus on the environment and sustainable development, the competition will select 40 students as finalists, who will tackle some of the planet's most significant environmental challenges, dubbed Operation Green, with the winner chosen in October in Washington D.C.

Yamada, a 13-year-old from Kula, said his favorite subject in school is science.

"I feel that science is all around us and it is the explanation of everything around us that is science. You just have to recognize the significance of what you are seeing," Yamada wrote in the essay accompanying his application in the Top Young Scientist contest.

In its ninth year, the Discovery Channel Young Scientist Challenge is described as the nation's premier science contest for students in grades 5 through 8, designed to encourage the exploration of science during the middle school years.

Discovery Communications launched the competition in partnership with Science Service to nurture the next generation of American scientists at a critical age when interest in science begins to decline.

Yamada was a 2007 Maui District representative in the Hawaii State Science Fair with a project titled: "Which Drinks Demineralize Teeth Most and Can Fluoride Remineralize these Teeth?"

He explained his project in his application to the Discovery Communications competition.

Yamada said he was surprised to learn that vitamin water and sports drinks demineralized teeth between four and eight times more than Coke and Diet Coke. "According to the results, it is best to drink water, Coke, or Diet Coke to maintain good health," Yamada wrote.

With the help of his parents, Dr. Daryl and Joyce Yamada, both in the dentistry field, and donations from two local oral surgeons, Tyler carried out his science project by using 168 extracted human teeth and placing them in various jars with his testing liquids, which included distilled water, Coke, Diet Coke, Gatorade, Red Bull, sugar free Red Bull and Propel. Three trials were completed over several weeks.

As a semifinalist, Yamada was selected from 1,960 formal entries chosen from a pool of 75,000 students who entered science fairs nationwide. The contest identifies and honors those who best demonstrate leadership, teamwork, scientific problem solving and the ability to be an effective science communicator.

Yamada is an Iao School Renaissance scholar, having won $100 scholarships in social studies and in science.

He plays the tuba in the Iao Band and is a member of the school's Robotics Team and Science Club. He is the Shark Patrol leader in Boy Scout Troop 40 at Wailuku Hongwanji Mission and attends after-school Japanese School. He's also involved in track and was a History Day state winner.

Nearly 16,000 children have entered the Top Young Scientist challenge since its inception in 1999. Winners have received approximately $700,000 in scholarship awards and federal government recognition, and have participated in science-related trips that have taken them around the world.