Since 1969, the Exploratorium has merged science and fun with its hands-on collection; now, it brings that curatorial savvy outdoors, with 20 interactive exhibits that investigate everything from water and wind to sound and light. Bridge Thermometer demonstrates how the Golden Gate can gauge temperature; Tasting the Tides creates a bayside water fountain; and Corrosion Wedge reveals the secret life of historic waterfront buildings. The exhibit has been two years in the making, and it's guaranteed to teach you a thing or two about the phenomena right before your eyes.