When I was little, I wanted to be an inventor. Not the next Edison, perhaps, but at least Caractacus Potts, who built "Chitty Chitty Bang Bang," or Bernie in the "Sugar and Spike" comic books.

Alas, unlike those fictional whizzes, I have never been able to fashion a teleportation device from an eggbeater and flashlight, or create a flying car. It's the 21st century and I really want a flying car. Maybe if I had visited the UW-Madison's physics museum as a child, I could have one by now.

As public school break draws to a close, a trip to the museum might encourage your own budding inventors, and demonstrate that science can be as much fun as vacation — at least when presented the right way.

The L.R. Ingersoll Physics Museum occupies room 2130 of Chamberlin Hall. It's a long, gold-colored chamber of hands-on exhibits overlooking University Avenue. The physics department's original pendulum clock ticks ponderously as busts of Newton, Tesla and Einstein glower over candy-colored amusements whose names sound as if they were drawn straight from a magic show.

Can you survive The Gravity Pit? What horrors are held by The Unequal Arm Balance, The Elastic Collision and The Torsion Pendulum? There's a mirror that reverses your image back to how others see you, plus Direct Current and Alternating Current generators, cut-away electric and internal-combustion motors, and my favorite: the simple Rotating Copper Disk, which shows how magnetic fields drag compass needles.

The disk is one of the original exhibits from 1917, when faculty set up what was then called "The Physical Museum" in Science Hall. It was one of the first institutions of its type in the country. That same year, and in a similar spirit of making physics useful, the department's ongoing spark-gap experiments became radio station 9XM, the precursor of today's Wisconsin Public Radio.

The museum has blossomed since it moved from Science Hall two and a half years ago, in the process more than doubling its size, says Steve Narf, instructional program manager.

"We've really been trying to bring it back to its heyday, like it was back in the 1920s," he says. "Basically we're out there to help promote physics and educate students who are coming through."

Adults are often as surprised as children when they visit and see scientific concepts become real. Take, for example, conservation of angular momentum. Wait — don't yawn. Get on the museum's rotating platform, hold the weights away from your body, and have someone give you a spin.

"It's like a figure skater," says Narf. "When they start to do a spin, they start out really slow, with their arms or legs out by their sides, far away from their center of mass. But when they bring their arms and legs in tight, they spin really, really fast." Presto! The conservation of angular momentum. The Winter Olympics may never be the same for you.

All the exhibits demonstrate scientific principles in mechanics, optics, magnetism and atomic physics. There are lots of computerized demonstrations as well, but the stars are the handmade mechanical monsters that convey delicate concepts. "Particle Physics Pinball," for example, shows how scientists determine the structure of sub-atomic particles.

"You scoop up a bunch of steel balls, a little less than a half an inch," says Narf. "And then with an air gun you blow them into a rotating, changing target you can't see. With precision you can determine what the shape of the hidden object is by how the particles bounce off."

Then there's the Earthquake Simulator, a miniature city of model buildings that demonstrates sympathetic resonance. "When you rotate the little wheel you can get the platform to resonate at whatever frequency those buildings are," says Narf. "If you do a real slow rotation you can get the bigger buildings to vibrate at one period, and the other ones won't. As you speed it up faster and faster you can see the others chime in, so to speak."

Or if your soul is so jaded that destroying cities or lobbing ball bearings from an air gun provides no pleasure, there's still The Probability Board, a thousand or so little metal BBs rattling in a glass case that you can flip to show probability curves.

"A lot of kids are drawn right to that," says Narf. Nearby is an electromagnet so powerful that a sign warns to keep wristwatches away.

The department's exhibits extend beyond the walls of the museum. Just inside the building's main entrance is a model of the Ice Cube Neutrino Observatory, showing probes glowing eerily as they drive nearly a mile into Antarctic ice to detect invisible particles traveling almost at the speed of light. The UW is helping construct the facility now. In the corner of the building opposite the museum is the physics department's plasma research facility.

"There's a big walk-around mezzanine picture window that shows the plasma torus for fusion research," says Narf. "It's a pretty interesting display how they have it all set up. They do all sorts of research into the world of plasma physics there."

There's also a portrait gallery of Nobel Prize winners going back to 1901, and glass cases in adjacent hallways that show off ancient scientific instruments: an early X-ray tube, microscopes whose gold-colored barrels look like jewelry, and mysterious jazz-age consoles full of polished brass and fiddly knobs set into dark wood; they're all still in the process of being labeled.

"We have a plethora of ideas," says Narf. "We get more and more exhibits made every year." He credits the museum's committee and the volunteer builders for making the displays possible.

Why go to all the trouble of making physics seem like magic, and then instantly taking the magic away?

In summarizing its public education efforts, the department likes to quote Einstein: "In the matter of physics, the first lessons should contain nothing but what is experimental and interesting to see. A pretty experiment is in itself more valuable than 20 formulae extracted from our minds."

IF YOU GO

The L.R. Ingersoll Physics Museum is open from 8 a.m. to 4:15 p.m. Mondays through Fridays in room 2130 of Chamberlain Hall, 1150 University Ave. It is free and open to the public. To schedule guided tours of the museum contact Steve Narf at (608) 262-3898 at least one week in advance. To make donations to help the museum expand, or for more information, visit www.physics.wisc.edu/museum.