George Pittman holds up a plastic soda bottle filled with rust-tinged water and a nail, and immediately captures the attention of a group of wiggly kindergartners at Stevens Forest Elementary School.
By the time class ends, Mr. Pittman and the children have discussed electricity, the corrosive effects of rust and the differences between solids, liquids and gases.
For 13 years, Mr. Pittman, a 53-year-old school volunteer, has been making science come to life for students at the Oakland Mills school.
Every Friday, armed with a variety of tools that include magnets, video tapes and pennies, Mr. Pittman, who works for the CIA, teaches youngsters how electricity, magnetism and other aspects of physics affect them. He works with students in kindergarten through fifth grade.
"I like to see the children learn," said Mr. Pittman, whose son and daughter graduated from the school in the late 1970s. "You can see them digest all their learning."
His science sessions provide a welcome and educational break for the students, said kindergarten teacher JoAnne Mezei.
"This provides an enrichment time and provides something creative for the children," she said. "He's like our mentor."
Mr. Pittman, who makes much of the equipment in the basement of his Oakland Mills home, keeps some of the tools at the school so that students and teachers can experiment during the rest of the week.
Throughout their years at Stevens Forest, students use the same equipment to learn about increasingly complex principles.
In first grade, for example, students learn about basic physics by sitting in a chair suspended from the ceiling and measuring their weight using a spring-loaded scale.
By the time the students reach the fifth grade, Mr. Pittman uses the same equipment to teach them about force, pulleys, levers and inclines.
"I'm using the same equipment in more sophisticated ways," he said.
Throughout the experiments, Mr. Pittman practices safety, using bicycle helmets, seat belts and his own steadying hands. He uses goggles when necessary and makes sure all his instruments have well-rounded edges.
He also tests his lessons at home before trying them out in the classroom.
"You can't waste time. Otherwise, kids will lose interest," he said.
During the lessons, Mr. Pittman encourages children to find the answers to scientific questions on their own.
"If you're in school and you're told the answer, you don't learn," Mr. Pittman said. But when students are allowed to discover the answers on their own, he said, those answers are "burned into your mind."
In a recent 20-minute lesson with a kindergarten class, for example, Mr. Pittman used a battery, electrical wire, alligator clips and a tiny light bulb to demonstrate an electrical circuit. The lesson was not lost on student Keith Trahan.
Electricity "is the stuff that keeps power on," said the 5-year-old as he slipped into a backpack and headed for home.