Piner High senior Allison Lopez was on her hands and knees Friday morning, fiddling with a marble and a foam tubing "rollercoaster" as a gaggle of fifth- and sixth-graders looked on.

"It slows and it can't get back up, it needs a lot of momentum. See right here? It needs more speed. What would make it go faster?" she asked the younger students.

After a few moments, Bellevue Elementary School fifth-grader Brian Mondragon piped up.

"Hey guys, what if we stuck these two together?" he said.

"Try it," Lopez said and watched the students get back to work.

The exchange was typical of conversations had at Piner High's first-ever science day Friday during which mostly sixth-graders from Bellevue, Schaefer Charter School and Olivet Charter School spent nearly three hours on the Fulton Road campus building rollercoasters out of foam, watching metals burn, launching paper rockets and creating slime.

"We mostly want to have students have a positive experience with science," said Piner physics teacher Steve Carpenter.

Carpenter started the program four years ago, sending senior science students into four sixth-grade classrooms to teach once-a-month, hands-on lessons. After a one-year hiatus, the program returned in the fall and expanded to include three schools and six different classrooms.

But Friday's event was a first.

By Joey Ruiz's estimate, it was a success.

The Schaefer sixth-grader got a rousing high five from classmate Kole Parker after his paper rocket launched high into the air.

"It was kind of a scary moment," Ruiz said. "You are nervous. Is it going to go far or is it going to explode right there?"

The program benefits Piner's students as much as the sixth-graders, Carpenter said.

"Students have to push themselves to understand the concepts a little more deeply than they might if they were just sitting in their classroom," he said.

The program's growth coincides with a decline in access to hands-on science in state elementary schools, according to a 2011 study.

Among 1,110 elementary school teachers surveyed statewide, teachers reported "children rarely encounter high-quality science learning opportunities in California elementary schools because the conditions that would support them are rarely in place."

Budget cuts and an increasing focus on English language arts and math scores as a result of greater demands posed by standardized testing and federal penalties have squeezed science out of many classrooms, teachers said.

"There definitely is a change. They don't have as much background knowledge," Kristi Erickson, Piner science teacher, said of some incoming high school students. "The STAR (Standardized Testing and Reporting program) has really dictated that."

Schaefer teacher Jeff Dreitzler said having Piner students present lessons once a month has been a boon for his fifth- and sixth-grade students.

"They give them a chance for hands-on learning, exposure that sometimes, in a homeroom, you don't have time to put together as consistently as you would like to," he said.

"They are extremely well-prepared and competent," Dreitzler said of the Piner students.

And they are fun, said Olivet sixth-grader Deven Kirtley.

"We are not just learning it with speeches and lectures and stuff, but learning it by having fun with projects and experiments," he said.

Just spending time on the Piner campus was exciting, said Adam Griffen, Kirtley's lab partner in slime making and a sixth-grader at Olivet.

"It kind of gives you a feeling of what high school is like," Griffen said.

"Like a glimpse of what's ahead," Kirtley said.

Staff Writer Kerry Benefield writes an education blog at extracredit.blogs.pressdemocrat.com. She can be reached at 526-8671, kerry.benefield@press democrat.com or on Twitter @benefield.