SPARTA-There's nothing wrong with throwing a few good eggs on the weekend; ask Chelsea and Rhiannon, two sixth-graders at the Sparta Middle School. The harder the better, they might even say. The two friends finished in first place in the Naked Egg Drop event this past Saturday at the northern regional tournament of the New Jersey Science Olympiad, a competition that tested the skills of students in biology, physics, chemistry, earth science, and computers and technology at Montclair State University. Sparta's team of 12 sixth-, seventh-, and eighth-graders finished in the top 10 among 17 competing middle schools from around North Jersey to advance to the state finals at Middlesex County Community College, March 15. The Science Olympiad, an international nonprofit organization, is designed to improve education, increase student interest, and provide recognition for outstanding achievement in science by both students and educators. Karen Martin, an eighth-grade life sciences teacher at Sparta Middle School and competition advisor, said every team member enjoyed the challenge. And that's what is most important. "They had a lot of fun," said the teacher. "It showed them that they can be successful and that science isn't necessarily just about reading out of a textbook; that science isn't just done in a lab, it's done by everyone." Chelsea and Rhiannon were asked to build an apparatus that would catch an egg and hold it in place without breaking after a progressive drop. Not a problem, the two girls first thought. "We didn't know what materials we were going to get, (only) that we'd have a half-hour to build it," said Rhiannon. In preparation for the competition, some days the girls would arrive at school early before classes to go over science theories. They discussed facts, processes, skills and science applications Dropping the egg would be the easy part. Catching the egg with a device made out videotape, Popsicle sticks, paper cups, and popcorn would be another matter. Rhiannon decided to drop. Chelsea would watch from the bottom of the stairs; first at 7 feet, then 14, and finally 21 feet. "I didn't look when I was dropping," said Rhiannon, her hand shaking nervously. "I didn't want to see it splatter." The teammates came away clean, though n particularly Chelsea, who said she can't wait to match wits with other kids from around the state in the finals. The competition, she said, gave her a feel for independent-thinking, a chance to develop a novel idea by herself. "It was our own idea," she said. "Nobody told us what to do. We got to choose theories we liked and see what theories actually come true." Chelsea said she might need to practice a few new theories. She said it may take dropping some eggs at home, but she knows she better ask first. "My parents would probably kill me," she said. "They'd probably want me to do it outside."