Saturday’s Science Carnival, by far the Cambridge Science Festival’s largest event, was a great success. The Festival now fills Cambridge high school’s huge main gym plus a basketball gym plus the tennis courts just outside with a remarkable range of mostly interactive science exhibits and completely enthusiastic proponents. Thousands of families came, and not just for the wildly popular robot zoo. I enjoyed volunteering, mostly helping exhibitors carry in their wares—everything from human-size chess pieces to kites to amazingly complicated robot prototypes. I ended up with a stint helping Terry Murray (the Inventor Mentor) launch rockets on the high school’s sunny front lawn. Young kids and their parents got a big kick out of launching water-bottle rockets with stuffed animals on top. So did I.