When science barges into summer

Cameron Cashdollar, 7, smiled as Robert Walters helped her pinch the hind legs of a blue claw crab on Sunday, aboard the Science Barge in Yonkers.

She didn’t flinch as the crab’s indigo legs extended and wriggled before a crowd of children waiting for their turns to hold the clawed creature.

“It was cool,” Cameron said. “It’s hard and wet. The front legs were moving, but not the back legs.”

Mr. Walters, director of the Science Barge, urged the children to “let the crab know you’re in charge” by exhibiting confidence. He beckoned the kids away from an arts and crafts table with promises that handling the creatures they captured from the Hudson River was “the chance of the lifetime.” He then flipped over the blue claw crab, showing the nearly 30 workshop attendees that male crabs’ stomachs resemble a spaceship while females’ abdomens are triangle-shaped. Or, he joked, that kids could look for the orange claw tips on female crabs, because according to folklore, “the women paint their nails.”

The Science Barge was built by NY Sun Works and acquired by the environmental group Groundwork Hudson Valley in 2008. During the work week Mr. Walters and barge art director Jamie Korb show how solar panels, wind turbines and a little biofuel –– six gallons in six months –– power a greenhouse on the barge for visiting school groups, farmers and environmentalists. The greenhouse uses rainwater to grow peppers, cucumbers, melons, lettuce and other produce in non-soil materials such as clay beads and rock wall, which has a texture similar to wall insulation. Such hydroponics gardening techniques offer urban families with small spaces ways to grow their own produce, according to Mr. Walters.