Taking three-hour naps after school helped Fairfax High junior Soo Choi come up with her science fair project. Her mother didn't like her taking naps for so long, because she thought it was unhealthy. Choi wanted to see if that were really the case, so she tested the internal clock of two plants. The results became her project.

"I really liked imitating other scientists," Choi said.

Last week, 183 students participated in Fairfax High's science fair, with topics ranging from the effect of temperature on ball-bounce height to investigating various bridge designs under stress to the effect of chewing gum on comprehension test scores.

The winners of last week's science fair will compete in a regional science fair in Virginia.

Choi found that the plant that "slept" at night and received sunlight during the day was healthy, while the other plant that slept during the day didn't do so well.

"You need your own data, you need your own research, you need your own conclusion," Choi said.

Many students participating in the fair take honors science classes at Fairfax. Students say that the projects, while worthwhile, can be time-consuming.

"It takes a lot of time," said Laura Slonina. The sophomore, who likes biology and is considering taking Advanced Placement biology next year, studied the effect of common salt on E. coli K12. Last year, she did a similar experiment with MSG.

Ninth-grader Nick DeSantis agreed. His project, hydraulics in motion, tested the effect of speed on a hydraulic system.

When asked what he most enjoyed about the process, he said, "putting the project together."

Science-fair coordinator and earth-science teacher Edie Moore said she's impressed by the creativity that the students show. She said the science- fair judges — alumni, parents, members of the local business community — feel the same way.

"The judges were amazed by the depth of understanding," Moore said.