I went bungee jumping just once, in 1992, and I didn't expect to hook up with a bungee cord ever again. After I had signed a waiver in seven places, I dove head-first from a 72-foot tower, feeling nothing but animal terror until the powerful nylon-and-rubber cables kicked in to pull me this way and that. When I realized I wasn't about to splatter, an endless smile swept across my face.

Still, once was enough.

Until a couple of weeks ago, that is, when I checked out a less daunting but still way-cool bungee-trampoline hybrid at the Carnegie Science Center on the North Shore.

Traditional thrill-seeking, daredevil bungee jumping from bridges and in amusement parks is hard to find these days -- perhaps because at least 20 people have died in bungee accidents worldwide since 1986, according to the Web site www.rideaccidents.com. But the Science Center's closer-to-the-ground Bounce Trampoline, in operation since 2001, is not about defying death. It's about kids bouncing, flipping and swinging like George of the Jungle while they learn at least a little about the science of potential and kinetic energy.

The exhibit's safety record, according to Mike Marcus, director of marketing, "on balance is perfect. There are no injuries of significance. Somebody might have felt like they pulled a hamstring. There's never been anything that anybody had to get medical attention of any type."

The interactive exhibit consists of a roughly 15 by 15 foot octagonal trampoline and two metal uprights rising to 20 feet. Attached to each post are eight bungee cords with a combined pressure on each side of 120 pounds. A child, college student or adventurous adult is strapped into a harness that goes around the back, between the legs and under the buttocks. The person is weighed and then hooked up to the right number of bungees for their heft -- 230 pounds is the limit.

Watched over by a trained "jump master," the kids begin to bounce, rocketing higher and higher. They are encouraged to try back flips (relatively easy) and front flips (more difficult). Each person spends a minute and a half in this exhilarating limbo -- quite enough for a middle-aged jumper, I can attest. Watched over by jump master Rachel Chunko, I managed two back flips with no difficulty. But when my 90 seconds were up, I lay down on the trampoline, thoroughly winded.

Because it's the Science Center, participants are taught something about the science behind the sizzle.

"Once they're waiting in the queueing area and they get their harness on, that's when we get a chance to talk to them about the exhibit," says Jana Smith, coordinator of SportsWorks.

"We explain that potential energy is the buildup of the energy. When you're coming back down, gravity pulls you down to the mat. Potential energy is building up in the bungees. When the child gets to the mat and the springs on the mat stretch and their knees bend, their body has built up potential energy, the mat has potential energy.

"As soon as they release and jump back in the air, you have the kinetic energy, where the bungees pull them up and the springs from the mat push them up and their own energy and the bending of their knees and the jumping pulls them up."

On a recent Friday, people crowded around the exhibit nonstop. Fifteen or 16 kids stood in line at any time, and another three or four sat on deck in their harnesses. Moms and dads shot photos and video and cheered their children on.

Jump master Robert Marshall, a thin, sinewy twentysomething who was always clapping his hands or bouncing around on his Nikes, was moving fast -- buckling and unbuckling cords depending on a child's weight, raising and lowering the hydraulic uprights (not unlike pulling on weight machines in a gym) and keeping children from bouncing to the trampoline's edge.

"His job is to make sure that the person jumping on the trampoline is high enough before they start flipping, so that they don't end up coming down on their head on the mat," Smith said, "and just make sure that the person doing the jumping is safe at all times up there."

How much science do the kids learn? I asked a few what the exhibit was about.

"Gravity, I guess," said an 8-year-old boy. "Like, you can stay up in the air for a long time or something, you can do like flips up in space and stuff."

"The cords are making you go up and down, bouncing you and making you flip," a 10-year-old girl said.

Maybe that's as much as you can expect from a short lesson. Like exposing children to classical music, a seed begins to sprout.

In any case, there's no question that the Bounce Trampoline transforms what could be a classroom snooze into an ecstatic minute and a half.

Angie Giuffre, 9, visiting from Virginia Beach, Va., wore an intense look as she pushed higher and higher and then did back flips that sent her long brown hair flying.

"It's one of my favorite things to do," she said.

Call 412-237-3400 for Carnegie Science Center hours, exhibit information and prices.