For students at Cambridge's public schools, science means labs and textbooks four days out of five. But on the fifth day, Harvard students come to volunteer, and race-cars made out of mousetraps speed across classroom floors.

"Harvard students add a youthful element to teaching," says Linda A. Ferullo, a second-grade teacher at the Tobin School.

The project is just one of several being taught by Harvard students as part of a larger program called ExperiMentors.

ExperiMentors, founded in the fall of 1993 and sponsored by the Phillips Brooks House Association (PBHA), sends pairs of student volunteers to Cambridge public schools to teach science. The program has reached over 1000 children since its inception.

The volunteers visit each class every week for one hour, teaching children everything from the principles of sound to the anatomy of the human body.

The program's goal is "to take science in the classroom one step further," according to President Jennifer L. Morazes '96.

Morazes added that the program shows children that anyone, including women and minorities, can become a scientist.

Greg S. Sawicki '97, ExperiMentors' PBHA cabinet representative, said the organization is looking for donations from science organizations to fund their operations. ExperiMentors is presently supported by Phillips Brooks House and a public service grant from President Neil L. Rudenstine.

"We are new and it is just a matter of time before we are properly funded," he says.

The program, which consists of about 100 volunteers, currently runs three separate projects.

By far the largest effort is one in which about 70 undergraduates teach science units in kindergarten through eighth grade classrooms at the Fitzgerald, Tobin and Peabody Schools.

According to Morazes, this program offers the most flexibility and freedom in what is taught; volunteers are assigned to a class, create their own lesson plans with help from teachers, and deliver eight lessons per semester.

At the end of the semester, high school students will enjoy a day-long field trip to Harvard for tours of laboratories and museums. The younger students will present their projects, which the undergraduates will help them design, to other classes in science days held at each of the participating elementary schools.

About 10 to 20 student volunteers, mostly science concentrators, also began teaching in science classes at the Cambridge Rindge and Latin High School this fall.

"The philosophy of this particular program is to provide positive role models and show diversity in the scientific community," says Moupali Das '96, a biochemical sciences concentrator and the coordinator of the high school program.

Volunteers not only teach, but also participate in such activities as college advising, Das adds.

"Volunteers are more than just teachers. They are resources for students, almost like big siblings," she says.

Unlike the volunteers in the elementary schools, who have a lot of latitude in choosing what to teach, high school ExperiMentors are much more constrained by a set curriculum and syllabus, Das says. Current volunteers teach honors chemistry and introductory biology classes in the high school.

Das says high school teachers were initially reluctant to give up classroom time to volunteers. "They offer little freedom, because of AP's and other standard tests," she says.

But Das notes that the teachers were pleased with the volunteers' work this fall. "The competent, outgoing volunteers have done good jobs and have received positive feedback from both teachers and students," she says.

"I cannot say enough positive things about the program," says Elsie Murphy, a sixth grade teacher at the Fitzgerald School. "The volunteers truly connect with the children."

Sawicki says the volunteers' youth appeals to the children. "The kids are responsive to younger fresh faces that they can look up to," he says.

Students engage in a variety of hands-on projects, from constructing thermometers out of shoelaces and cardboard to making lungs out of straws to show the effects of smoking, says Morazes.

The group plans to exhibit these projects at Harvard at the end of this semester, she says.

Sawicki, who describes teaching science to kids as his "life-love," says he feels he's making a positive impact on the children.

The volunteers insist they are not there to upstage the teachers.

"Volunteers aren't to take the place of teachers, who are capable and competent," says Morazes. "The purpose is to supplement."

"They learn the cutting edge of science with the unique perspective of the Harvard student," Morazes says.

Ten ExperiMentors now help train Science Olympiad teams at the Peabody School (K-8) and the Cambridge Rindge and Latin High School.

The Olympiad is a national competition in which teams across the country prepare for several "events," with such names as Mission Impossible, Trajectory and Mousetrap Racer.

For example, Mission Impossible calls for students to demonstrate energy transfers by creating a contraption using assortments of blocks, strings and balls.

Students will have to demonstrate their projects at the Olympiad's state-level competition, to be held this year at Worcester Polytechnic Institute. At the contest, they will also be required to tackle such scientific challenges as identifying mystery compounds using chemical lab techniques, according to Science Olympiad coordinator Hsien Y. Wong '96.

Wong, an applied math concentrator, spends an hour after school each week helping a handful of sixth to ninth graders prepare for the competition. He says he finds ExperiMentors very enriching because it allows him to communicate directly with the children and get them interested in science.

"According to the teachers, this is the year we have the best chances of winning," he says.