The California Academy of Sciences in Golden Gate Park is home to the Museum of Natural History, the Steinhart Aquarium, and the Morrison Planetarium: http://www.calacademy.org
The Lick Observatory, on Mount Hamilton, south of San Jose, is a world-class astronomical observatory operated by the University of California. http://ucowww.ucsc.edu/
The Lawrence Hall of Science, is located in the Berkeley Hills, above the campus of the University of California. It has a science museum, a small planetarium, a science store, a cafeteria, and also offers science enrichment classes for children. http://www.lhs.berkeley.edu/
The Egyptian Museum of the Rosicrucian Order, in San Jose, California, has the most extensive collection of ancient Egyptian arifacts on the West Coast. http://www.rosicrucian.org/
The Tech Museum of Innovation in San Jose is oriented to teaching high technology to students. It also houses an Imax theater. http://www.thetech.org
The San Francisco Bay Model Visitor Center, in Sausalito, is a huge, indoor, scale model of the San Francisco Bay, built and operated by the U.S. Army Corps of Engineers: http://www.spn.usace.army.mil/bmvc/
The Monterey Bay Aquarium is a spectacular aquarium specializing in the life native to the Monterey Bay area on the central California coast: http://www.mbayaq.org
The Steinhart Aquarium in San Francisco's Golden Gate Park has extensive salt and freshwater environments from around the world: http://www.calacademy.org/aquarium/
Yosemite National Park, in the Sierra Nevada Mountains, has two web sites: One is operated by the National Park Service: http://www.nps.gov/yose/ . The second is operated by the contractor which provides visitor services, lodging, dining, and stores: http://www.yosemitepark.com/
Muir Woods is a beautiful coastal redwood grove in Marin County, just across the Golden Gate from San Francisco. It is operated by the National Park Service. http://www.nps.gov/muwo/