Just about anyone will tell you that admission to an aquarium is a hefty price to pay just to watch air shoot up a tube.

Not my kid.  

The National Aquarium in Baltimore is one of her favorite places on the east coast.  This acclaimed status is not because of the four-story waterfall; the brilliantly designed exhibits that let you stand right next to a school of fish, no matter how tiny you are; the center tanks where hand-sized silver fish and a healthy number of sharks swim around you.  The dolphin show is fun too, she says.  But where do we end up?  Always?  At the rows of transparent tubes near  'Wings on the water,' where rays of all shapes and sizes glide beneath the crowds.  Just beyond, a display features miniature seahorses the size of my little finger.  A few steps away, we can sit by a tank's underwater observation window and possibly come nose to nose with a dolphin.

That's all well and good.  After we visit the bubble tubes.   She can't get her arms around one yet, but she'll make a good attempt.  She'll press her ear to the plexi and listen for the "glonk!" that signals a series of huge, gorgeous, bubbles is about to rise.  She'll weave her way between the tubes pointing out the bubbles to passer-by.  She's the bubble ambassador.  Just try to take her to see something else before she's ready to go.  Go ahead and try.