With spring sports starting and SAT tests around the corner, you might not expect local high school students to be thinking much about solving the world's energy problems or tackling complex health issues. But about 175 teens at Crescent Valley High School have given a lot of thought to such weighty topics recently.

The honors science students are headed to the Central Western Oregon Science Expo on Friday and Saturday at Western Oregon University, where they hope to be rewarded for months of hard work and research.

The two-day science competition - co-sponsored by the Oregon Junior Academy of Science, the Junior Science and Humanities Symposium and the Regional Intel Science and Engineering Fair - will take place in the Werner Center on the Monmouth campus and is open to the public. The students' projects will be on display from noon to 3 p.m. Saturday.

Juniors Curtis Peterson, Raymond Ehlers and Sean Skyllingstad have been working on their project for two years.

The team of sophomores investigated whether activated charcoal could be used to filter the toxic and corrosive levels of hydrogen sulfide (H2S) in the gas produced by the Coffin Butte Landfill. Removing the hydrogen sulfide is necessary if fuel-cell technology is to be employed to convert the landfill's methane gas into electrical power, the teens explained.

Last year's work earned them a trip to Intel's international science fair in Albuquerque where they placed third in "Team Projects."

This year's entry is a continuation of that research and seeks to evaluate whether activated charcoal can be "washed" with water after the filtering process. Regenerating the charcoal would make it a reusable resource and improve the technique's cost effectiveness.

"We wanted to do something that would obviously produce a large-scale benefit," said Skyllingstad.

The landfill has been seeking a solution to the H2S problem for about five years, Ehlers added, but theirs is the first which might turn out to be cost-effective.

Another group of students - Margaret Yeh, Inis Hsieh and David Ni - worked on a project that analyzes the potential for extracting lipids from algae to produce crude oil. Their team mixed hexane and water with small amounts of algae in test tubes and then used a centrifuge to separate the fatty acids from the algae. Ni explained the lipids float to the top in the hexane and it can then be turned into a renewable source of fuel, perhaps to be used as a biomass source for producing biodiesel.

This team of juniors entered their algae experiment in last year's competition as well. They built on their previous research this year by comparing the lipid content between wild algae and that grown in a lab.

Molly Doran, Mackenzie Entrikin and Kelsey Ward studied the impact of sea spray on the efficiency of solar panels, while Riti Gupta and Teresa Chan researched the possibility of using cellulose nanocrystals to increase the efficiency of microfilms used in hemodialysis machines. Other students studied the water quality of the Corvallis watershed, explored wave energy, attempted to harvest antibiotics from naturally grown herbs and analyzed the impact of different chemicals on various species.

Every student in the Crescent Valley science program is required to do a science project during the school year, but those who go the extra mile to produce an advanced project to enter in the regional science expo receive honors credit.

Very few schools send as many students to the annual competition as Crescent Valley, according to physics and chemistry teacher Adam Kirsch. He and the other science teachers believe "if you're going to learn science, you've got to do science."

Research shows active learning is much more effective than standing in front of a white board and talking, Kirsch explained. A large portion of each class still employs the traditional approach, but about 15 percent of class time is spent giving students more control to explore science on their own.

"We're not entirely project-based, but many of the science staff here believe kids need to be given opportunities to pick a problem that means something to them and to find a solution or at least investigate what will work and what won't to resolve that problem," he said.

Gupta said she's enjoyed working on her project because it's preparing her for the future in which she hopes to go Stanford University or University of California at Berkeley for college. "It's a good start, because I really want to go into medical research," she said.