.bodytext {float: left; } .floatimg-left-hort { float:left; margin-top:10px; margin-right: 10px; width:300px; clear:left;} .floatimg-left-caption-hort { float:left; margin-bottom:10px; width:300px; margin-right:10px; clear:left;} .floatimg-left-vert { float:left; margin-top:10px; margin-right:15px; width:200px;} .floatimg-left-caption-vert { float:left; margin-right:10px; margin-bottom:10px; font-size: 10px; width:200px;} .floatimg-right-hort { float:right; margin-top:10px; margin-left:10px; margin-bottom:10px; width: 300px;} .floatimg-right-caption-hort { float:left; margin-right:10px; margin-bottom:10px; width: 300px; font-size: 10px; } .floatimg-right-vert { float:right; margin-top:10px; margin-left:10px; margin-bottom:10px; width: 200px;} .floatimg-right-caption-vert { float:left; margin-right:10px; margin-bottom:10px; width: 200px; font-size: 10px; } .floatimgright-sidebar { float:right; margin-top:10px; margin-left:10px; margin-bottom:10px; width: 200px; border-top-style: double; border-top-color: black; border-bottom-style: double; border-bottom-color: black;} .floatimgright-sidebar p { line-height: 115%; text-indent: 10px; } .floatimgright-sidebar h4 { font-variant:small-caps; } .pullquote { float:right; margin-top:10px; margin-left:10px; margin-bottom:10px; width: 150px; background: url(http://www.dmbusinessdaily.com/DAILY/editorial/extras/closequote.gif) no-repeat bottom right !important ; line-height: 150%; font-size: 125%; border-top: 1px solid; border-bottom: 1px solid;} .floatvidleft { float:left; margin-bottom:10px; width:325px; margin-right:10px; clear:left;} .floatvidright { float:right; margin-bottom:10px; width:325px; margin-right:10px; clear:left;} You know the Foucault pendulum at the Science Center of Iowa? It’s a big, shiny ball on a long cable, and it proves that the Earth is rotating, just in case you’re having any doubts. Everybody loved that thing at the old Science Center, so of course they brought it along when they moved to the new facility.

You might describe it as a bit of magic or a scientific marvel or just a nice way to kill a couple of minutes. Unfortunately, some parents see it more as a carnival attraction. They like to place a kid on the ball and treat their unspoiled darling to a joy ride.

The Foucault pendulum functions perfectly in accordance with the mystical forces of the universe. But an extra 50-pound load can really foul up the works.

Science Center Executive Director Mary Sellers shared this information when I went over to give her a bad time about nonworking exhibits.

Instead of pointing fingers back at the newspaper industry, which occasionally, once in a great while, makes a mistake in print, Sellers took the mature approach and noted that lots of things can go wrong when you open up 160 exhibits to every kid whose parent or school forks over the price of a ticket.

She didn’t say, “You try it, smart guy,” and hand me the front-door key, even though that’s what I secretly hoped for. (The key, I mean. I’ve always wanted to live in a place with high ceilings, good access to downtown and an IMAX theater.)

Along with the good old pendulum, the Science Center opened in 2005 with exhibits the world had never seen, and most of them worked out fine. But it’s hard to build anything that can withstand humankind’s potent blend of curiosity and bad judgment.

One exhibit was intended to let visitors experiment by attaching different propellers to air boats. It was designed so eager knowledge-seekers could reach through a hole and change the propellers. But as long as they had their hands in there anyway, people often decided to give the boats a push. Not what the designer had in mind.

“The boats would break constantly,” Sellers said. “The exhibit just couldn’t handle the scale of the interaction.” Again, a nice way to put it. Nothing about “grubby little paws” or anything like that.

By the way, “couldn’t handle the scale of the interaction” is an extremely handy phrase that can apply to everything from automobile bumpers to the Iraqi parliament to the Kansas City Royals, so you might want to jot it down.

My original complaint came about because a kid who spent the afternoon at the Science Center reported that five or six exhibits failed to function.

Sellers doesn’t deny that the mechanical devices in her $62 million showplace sometimes go kerflooey. She does point out that the staff tries to keep problems to a minimum by cruising through the museum every hour, looking for broken equipment and movable parts that have been moved way across the room by apparently demon-possessed – but adorable – youngsters.

Don’t get all creeped out, but sometimes staff members even follow people on their path through the facility, carefully taking note of what they do and how they do it. So keep it clean.

The organization also hired experts from Chicago – what, nobody in Des Moines owns a clipboard? – to interview patrons this summer about their Science Center experience. “We wanted to know, did we get it right?” Sellers said. “I think we got a lot of validation.”

As for you and your rugrats, all the Science Center staff expects is that you behave like responsible guests. Follow operating instructions. If the tennis balls are missing from the ball-rolling race, look on the floor before launching into a tirade. Remember, the fire alarms are not exhibits. And do not plan on giving your kid a ride on the Foucault pendulum; the museum built a four-foot glass wall around that temptation.

With all of this new information in hand, I reported back to the original complainant. He listened to my recap of Sellers’ points and then said, OK, but the golf ball catapult never has worked right.