Their friends called the idea "gross'' and even their parents rolled their eyes when four Bexley eighth-graders revealed plans to compost roadkill into fertilizer.

But the "Now You See It, Now You Don't'' project tickled the fancy of the judges for a national science competition so much that they're giving the girls a free Disney World vacation, plus a shot at $36,000 in scholarships and a $25,000 grant.

"When I told my dad, he was like, 'Why on earth had we chosen this topic,' '' said Carrie Schedler, 14. She worked on the "mortality composting'' project for five months with Sarah Friedberg,14; Emily Roth, 14; and Kathryn Scurci, 13.

"One of my friends was extremely supportive, but everyone else was like, 'That's disgusting.' ''

No one's cracking jokes now, since the girls gathered in the middle-school office Tuesday for a telephone call informing them that they were winners.

"The lady told us, 'You'd better pack your bags,' and we all started screaming and jumping up and down,'' Schedler said. "Since then, all these people who have never talked to me in my life at school have come up to congratulate me.''

Jon Hood, a seventh-grade Bexley Middle School science teacher, selected the girls to create a project for the Christopher Columbus Awards competition, held annually to encourage middle-school students to explore scientific solutions to community problems.

Hood has had teams participate in the competition the past two years, with one group winning the trip and college scholarships.

The road to roadkill composting started in September with a brainstorming session in which the girls tossed around topics ranging from tire traction on wet roads to frozen fire hydrants. After hearing about the overpopulation of deer in Ohio and studying landfills with Hood in seventh grade, they settled on the composting idea.

Field trips to the Kurtz Brothers composting on Rohr Road on the South Side and an Ohio State University composting-research center in Wooster gave the girls the knowledge to set up three compost piles in November.

They packed sawdust and yard waste around a roadkill groundhog in one. In another, they placed a dead cat in a pile of yard waste. In a third, they laid two euthanized dogs in a pile of ground-up wood pallets.

For more than a month, they monitored the temperatures, acidity levels and moisture content of the piles. Then they uncovered the animals and weighed them.

"The groundhog was flat as a pancake,'' Roth said. Fur and bones so brittle that you could crush them between your fingers were all that remained of that and the cat; about half of the dogs' bodies were decomposed.

Composting, the girls concluded, is a simple, environmentally safe way to dispose of animal carcasses.

OSU researchers have concluded that sawdust is the best composting medium to use with carcasses -- no odor or contamination is created, and the dead animals disintegrate completely within months.

"Composting them is a great option all around,'' Friedberg said. "You don't have to fill up landfills. It just goes right back into the soil. I think it's a world-changing idea, really.''

A mortality-compost site in Wooster is used to compost some of the more than 11,000 deer killed yearly on Ohio roads. The girls hope if they win the top prize in the competition -- a $25,000 grant to put their project into action -- that composting animals will become common in Ohio.

Their project was the only one from Ohio to make the semi-finals, where it competed against 29 others. The students will join nine other groups for the finals at Disney World June 20-26.

Not surprisingly, the nature of their project still generates humor.

"My mom tells my dog Eddie that if he isn't good, he's going to the compost pile,'' Scurci said.