Science File / An exploration of issues and trends affecting science, medicine and the environment

Interactive displays, electronic games and life-size dioramas illustrate the story of extinctions in an exhibit now at the Natural History Museum of Los Angeles County in Exposition Park.

“Our Weakening Web: The Story of Extinction,” explores more than 500 million years of the Earth’s natural history, giving a historical perspective on extinction and examining the situation as it exists today.

The exhibit runs through Aug. 27; call (213) 744-DINO.

SCIENCE FOR FAMILIES

* Families can meet live animals from Wildlife on Wheels at storytelling sessions in various local libraries through Saturday. For times and locations call (818) 951-3656. * Children and adults alike can experience “Sharks, Phantoms of the Santa Barbara Channel,” at the Santa Barbara Museum of Natural History through Sept. 4. Workshops, exhibits and labs explore one of nature’s most enduring and misunderstood creatures. (805) 682-4711. * Children can learn about the science of sound, the importance of clean water and magnetism in workshops offered at Kidspace Museum in Pasadena. For class descriptions and times, call (818) 449-9144.

* The Children’s Museum at La Habra is holding noon health workshops for children. On Saturday, “Fun With Pharmacy” is scheduled. “Body Basics” will be held Aug. 12. (310) 905-9793.

* Butterflies will be studied in a workshop sponsored by the Friends of Madrona Marsh at the marsh nature preserve at 2 p.m. Aug. 13. Reservations are required; (310) 32-MARSH or (310) 782-3989.

MARINE SCIENCE

* A series of daylong educational cruises to the waters of the Channel Islands National Marine Sanctuary led by sanctuary naturalists and Santa Barbara Museum of Natural History Sea Center staff will offer a look at the diversity of marine life there. The next trip will be Aug. 20. Preregistration is required; (805) 963-3564.

* The grunion have been arriving on local beaches every full and new moon for their annual mating ritual. The Cabrillo Marine Aquarium will conduct a “Meet the Grunion” program at 8 p.m. Saturday. (310) 548-7563.

* Bioluminescent animals, such as the mud-dwelling sea pen, which lights up like a sparkler when touched, will be examined in night cruises hosted by the Orange County Marine Institute. Space is available on the Aug. 25 and 26 cruises, both at 8:30 p.m. Reservations are required; (714) 496-2274.

ASTRONOMY

* The Los Angeles Astronomical Society, Pomona Valley Astronomers and others will be on hand for a public star party at the Griffith Observatory on Aug. 5. (213) 727-7909 or (213) 664-1191.

* Observing and tracking the thousands of satellites orbiting the Earth will be the subject of the astronomy program at 8 p.m. Friday in the business building, Room 111, at Santa Monica College. (310) 452-9396.