By the time Helen P. Mihm finishes telling the students to come and get their cranes, the children are crowded around the front of the classroom, taking their magnetic kits.
"You need to connect your alligator clips to the crane," she tells them as they wire the tabletop crane, the AA-size battery and the miniature switch.
In minutes, chains and clumps of paper clips dangle from little wood and metal cranes, and the volume in the art room at Benfield Elementary School is high.
One pair of children challenges another to see whose crane can pick up the most paper clips. Another child decides to add a buzzer to the electrical loop. Yet another team bolsters its crane's power by adding a D-cell battery to the circuit. There is shouting and laughter among the third- , fourth- and fifth-graders.
The four-session programs on electricity have become so popular that Mrs. Mihm, 40, has had to run two of them this year at the Severna Park elementary school. The class has room for 14 children, whose families pay the $40 fee. By the end of a recent session, the children were charged and ready to apply what they had learned.
"I have to rewire my Erector set," said Jonathan Schmidt, 8.
"I'm probably going to go buy my own electric alarm so I can keep my brother and sister out of the room," said Mike Osborne, 10.
That type of enthusiasm is what Mrs. Mihm wants to bring about with her demonstrations. She and her husband, James W. Mihm, run Science Wizards Inc. from their Annapolis home, bringing science to the county's elementary students.
"It's rewarding. It lets me teach science the way I think it should be taught," said Mrs. Mihm, a former Fairfax County, Va., junior high school science teacher. "Everything is oriented toward having the kids do it."
Her husband, a 44-year-old marine biologist, designs the portable experiments. The couple's two children test the projects. Mr. Mihm quit his job as a Navy researcher six years ago to become a consultant and help start the family business.
"We see a big need for hands-on science at the elementary schools," Mrs. Mihm said.
The Mihms have been filling cartons with their boxed experiments and taking them to schools for five years. During the summer, the couple holds weeklong half-day camps at St. Martin's School in Annapolis.
The Mihms view the program as complementing the textbooks, videos and demonstrations children already get in elementary school science. Children don't get a chance to do many experiments as part of the regular curriculum because of the cost, time and preparation required.
Michelle A. Day, a Chapter I teacher at Rolling Knolls Elementary School, brought the Mihms to her Annapolis school with the help of several grants because they could fill a gap in her students' education. The third-graders were treated to two in-school club sessions of Science Wizards, while the fourth-graders did environment-related experiments and gave reports.
One environmental science experiment uses salad oil to replicate an oil spill that children clean with straws and dish detergent.
The mini-experiment format allows the children to work in pairs, test out theories and complete a few experiments in an hour, a pace that would be hectic if Dr. Mihm did not package each experiment in a tray his wife hands to students.
Ms. Day said she still remembers her first science experiment in school and knows the hands-on experience helps the children learn.
"If you expose youngsters to these things at a young age, they will always think in terms that there are lots of ways to put things together," she said. "They know things are explorable."
"It's great," Janiese Adams, 8, said as she wired a cardboard safe during a Rolling Knolls club meeting. "You get to do stuff we never did."