GOUVERNEUR — A Black River native and a Florida family are bringing entertainment and education to the 157th Gouverneur & St. Lawrence County Fair with bubbles and bears.

Jeffrey P. Boyer, who was born in Black River and now lives south of Albany in Kingston, is in his second year of performing science-themed magic shows at fairs in the Northeast.

"I love the fairs. The fairs are cool, especially up here. These are my folks," Mr. Boyer said. His performances are geared toward children ranging in age from 2 to 14. Presentations include blowing out a candle from across a tent, making hair stand up with a Van de Graaff generator, launching rolls of toilet paper at audiences and creating fog-filled bubbles.

"The real magic is science. Scienceismagic," said Mr. Boyer, who describes the secrets behind his tricks as he performs them. He creates his illusions, such as making a light bulb glow ostensibly on its own with the aid of a Tesla coil, out of unusual or interesting scientific phenomena.

"It's not enough to just say this is really neat. You need to be able to explain it," he said.

Maggie M. Smith, daughter of Deborah M. and David L. Smith of Canton, had an opportunity to stand inside a huge bubble as part of Mr. Boyer's "Bubble Trouble" show Thursday afternoon.

"I didn't know that bubbles could do that," the 9-year-old said. "It was fun."

Mr. Boyer enjoys his job, but has no plans to venture into the classroom.

"Science is really magical and really fun. It's tough to teach it in a classroom out of a book," he said. "It's a little too structured for me."

Elsewhere on the fairgrounds, the Rosaire's Bears show from Sarasota, Fla., is providing entertainment this week.Although the sign outside its caged arena announced "No trespassing: Violators will be fed to bears," crowds Thursday afternoon quickly learned that handfuls of treats would be the only things devoured during the show.

Five bears, sporting motorcycle-themed names like Chopper, Harley and Indian, walked on their hind legs, slid down a long metal slide, posed for a "Kodiak moment" and even drove a modified motorcycle around the sawdust ring to cheers from the audience.

"I think the kids enjoy it," said Derrick V. Rosaire, ninth-generation circus family member and son of Rosaire's Bears owner and head trainer Derrick Rosaire Jr. "The most important thing is to make sure the audiences enjoy it and the bears enjoy it."

Mr. Rosaire, 22, has been working with bears and other animals since he was 9. The bears are mostly ones that have been saved from euthanasia after parks closed down. The Rosaires have performed in Taiwan, Malaysia, Singapore and Bermuda as well as each state in the continental United States and every Canadian province.

Among the bears, which wear muzzles in the performance ring, are grizzlies and European and Himalayan brown bears.

"Sometimes we get a few people who are a little jumpy," Mr. Rosaire said.

However, 7-year-old MaCailla A. Allen, daughter of Scott Allen and Trudy Lennox-Miller of Gouverneur, said she was more excited than scared of the show. MaCailla especially enjoyed "the motorcycle one" and "when the bear licked the guy."

Eleven-year-old Shelby D. Peck, daughter of Abby and Wayne Peck of Croghan, added: "It's different that it's a wild animal they're training."

And how are the bears really fed, if not on stray audience members?

"Very carefully," Mr. Rosaire said, laughing. During the performance, audiences learn that a captive bear's diet includes white bread, lettuce, raw fish and a "super secret bear treat," hot dogs.

Rosaire's Bears will perform at 2:30, 5 and 8 p.m. today. Mr. Boyer's "Fun with Science" will be presented at 2 and 6:30 p.m., with "Bubble Trouble" at 4 p.m. Both shows take place at the fairgrounds behind Gouverneur High School at 84 E. Barney St.

Other highlights today include cow shows, dog agility shows and a 4-H Barnyard Olympics presentation. A monster truck show will take place at 7:30 p.m. in the grandstand, with tickets costing $10 for adults and $7 for children 12 and younger. The Dreamlands Amusement midway will be in operation from 1 p.m. to closing.

For a full schedule of events, call the fair office at 287-3010 or visit www.gouverneurfair.com.