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 today.

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

SCIENCE FOR FAMILIES

* A four-day science camp for children 7 to 12 will teach them how to identify constellations, stars and planets, as well as experiment with light and make scientific instruments to measure a star’s magnitude and altitude; 9 a.m.-2:30 p.m., Monday through Thursday, at the Launch Pad, 3333 Bear St., Costa Mesa. For reservations, call (714) 546-2061.

* 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.

* Discovery Science Center is hosting a lecture on forensic science conducted by Dr. Frederic Kakis, executive director of the National Institute of Forensic Studies, at 7 p.m. Saturday at the Launch Pad, 3333 Bear St., Costa Mesa. Cost is $5. Call (714) 540-2001.

* The Children’s Museum at La Habra is holding two weeklong computer camps for children from Aug. 7-11. Todayj is the last day to register. For price information and class topics, call (310) 905-9793.

ASTRONOMY

* The Riverside Astronomical Society members will show slides and lead a trek to view the night sky through giant telescopes at 7 p.m. Wednesday, at the Oak Canyon Nature Center in Anaheim. Admission is free. Call (714) 998-8380.

* 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.

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.

* 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.