Worms. They've been cut, diced and spliced in high school science classrooms for decades, but now one Temple University pharmacology professor believes he's found an innovative way to use the wiggly writhers to teach about the side effects of drug addiction.

Scott Rawls, of Temple's Center for Substance Abuse Research, has developed an innovative drug-abuse-prevention program that has science students in sixth through 12th grades soaking planarians — or flatworms — in various addictive drugs to observe the impact.

His program, Science Education Against Drug Abuse Partnership, is being used in more than 100 schools in four states and the District of Columbia.

"Seeing a living animal undergoing a transformation in their environment in response to addictive substances is powerful," Rawls said. "When students see an animal that is being impacted by a drug, I think they can relate to it themselves."

In Philadelphia — where 900 people died of drug overdoses last year — Rawls' program offers an alternative to long-standing drug-prevention programs often considered ineffective, like Drug Abuse Resistance Education (D.A.R.E), which urge kids to "just say no."

"If you tell someone not to put their hand in the cookie jar, they put their hand in the cookie jar when you're not looking," Rawls said. "We're showing these students the effects of addiction."

On a recent Monday in a science lab for juniors at Central High School in the city's Logan section, the students — many partaking in the home economics tradition of carrying around a baby doll to simulate parenting — put down their fake babies to pick up live worms.

The teens had just spent three weeks researching substances in which they wanted to soak their worms and studying how planarians' receptors for dopamine — a chemical that plays a large role in the brain's reward and pleasure systems — are similar to those of humans.

Now, the students were ready to soak the tiny, aquatic worms in everything from alcohol to nicotine. Of course, teachers can't bring heroin or other illegal drugs into schools for the tests, but Rawls said he hoped that by seeing what the legal addictive substances do to the worms, students would realize illicit substances produce even more dangerous effects.

Gaby Cruz, 17, and Alisha Diprimeo, 16, who said they drink coffee religiously, chose to soak their worms in caffeine.

"I heard caffeine is bad for you. I heard it dries out your skin and makes you hyperactive," Diprimeo said. "I'm interested to see how it works on a smaller immune system."

At the next table over, Tahira Bradley, Sidwel King and Nasire Riles, all 17, chose to bathe their worms in a solution of nicotine, the third most addictive drug for people.

"It seems like nicotine is in most people's lives in some way," Bradley said.

When exposed to nicotine, caffeine or other stimulates, the worms' mobility increases, but with a depressant like alcohol, their movements decrease. The students measure the movements by placing the clear petri dish with the worm on a sheet of graph paper and measuring how far it moves. They also count how many times the worms contract into a C-shape, another measurement of movement.

Rawls said students also can measure the worms' addictive behaviors by putting a piece of black construction paper under half of the petri dish. Flatworms prefer the dark, but if exposed to an addictive drug while they are on the light side of the dish, they begin to associate the rewarding effect of the drug with the light, and they'll keep going back to the light side, Rawls said.

"They are now seeking that drug, even if it means going into their least-preferred environment," he said.

During the experiments, the girls in the caffeine group saw their worms "really moving" when exposed to the substance, Cruz said.

"A lot of them are freaking out, especially the thinner ones," Cruz said. "I think it could be the same for humans."

Although they were surprised at what they saw, Diprimeo said she "won't think twice" about drinking coffee every day.

"I think I will continue drinking coffee until I start constricting like a planarian," she said.

For the students who soaked worms in nicotine, the experiment touched a nerve.

"Me, personally, I know I don't want to smoke, but looking at how the planarian reacted, I know why my thought of not smoking was a good choice," Bradley said. "It makes you think, 'That could happen to me.' "

King, her partner, agreed.

"Ignorance leads to irrational decisions," he said. "With awareness, we can increase prevention."

Sarah Tse, 17, whose team soaked its worms in an aspirin solution, said she only wished the experiments could have lasted longer.

"I wish you saw long-term effects, how it would affect their entire lifestyle if they lived in a pool of aspirin-filled water," she said.

Rawls hopes he'll be able to see the long-term effects of his program too. It's currently funded through the National Institutes of Health and through the National Institute on Drug Abuse. His program also is taught in classrooms in Pittsburgh, Washington, D.C. and cities in North Carolina, Virginia and New York, funded by a four-year grant that's already in its third year.

He hopes the federal grants will be renewed, and he hopes to get state and foundation funding.

For Rawls, the study of addiction — and his desire to help prevent it — come from a personal place.

"My dad was a Korean War veteran and a real cigarette smoker. It intrigued me that you had this tough guy who could not quit this habit," Rawls said. "That really turned me onto the idea of substance abuse and how it might actually be stopped."