Maia Nolan photos

Anchorage Museum director James Pepper Henry demonstrates the Hoist Chair in the BP Kinetic Space at the new Imaginarium Discovery Center.

James Pepper Henry is a goofball.

Well, not always. But he was one recent morning, when the usually-dignified director of the Anchorage Museum hijacked a media tour of the new Imaginarium.

When public relations coordinator Sarah Henning turned to point out signage in the new BP Kinetic Space physics gallery that puts exhibits into Alaska context, Pepper Henry jumped into a pulley-operated chair to show the group how he could hoist himself off the ground by pulling on a rope. As the small group of photographers and reporters moved from room to room, Pepper Henry popped up again and again, pointing out a tank full of moon jellyfish, showing off the "aurora in a box" and leaping in front of a digital projection of a seaside scene to show how he could draw new mountains into the landscape by waving his hands.

There were moments at which it was hard to tell who was having more fun: the museum director or the group of local elementary school students who'd been brought in so journalists could observe real live children interacting with the science exhibits.

To be fair, Pepper Henry isn't the only grownup who's gaga for the new and improved Imaginarium.

The new Imaginarium combines new exhibits, like a globe that simulates Earth and other planets, with classic favorites like the bubble room (in the background).

"We see a lot of adults geek out in here," Henning said as her boss lingered near the touch tank in the next room.

The Anchorage Museum expansion, which feels like it's been going on for eons but really began less than four years ago, includes a new home for the Imaginarium, the children's science museum that opened in its original location on Fifth Avenue in 1987. Now officially part of the Anchorage Museum, the new Imaginarium is 65 percent bigger than the original. About a quarter of the exhibits were conceived and designed specifically for the new center; others are Imaginarium classics or favorites from other science museums. (Longtime Imaginarium fans will be glad to hear the bubble room has been integrated into the new space. Gone, however, is the basement polar bear den with its fiberglass slide and urine-scented tunnels.)

General admission to the museum includes the 9,000-square-foot wonderland of science, where kids (and museum administrators) can simulate an earthquake, launch a hot air balloon, make a stop-motion film clip, drop balls into a multicolored kinetic sculpture, and record slow-motion footage of themselves jumping into the air.