Many organizations will offer science classes and...

Many organizations will offer science classes and workshops for youngsters this summer. Some offer financial assistance. Classes fill up fast, so early registration is recommended:

* The Natural History Museum of Los Angeles County hosts “Adventures in Nature,” July 17 through Aug. 4 for children 3 to 13. Week-long classes ranging from archeology to environmental geology will be available. Call (213) 744-3535.

* The California Museum of Science and Industry will hold its annual hands-on Science Workshops beginning July 10. Half-day, full-day and weeklong classes will be offered on rocketry, robotics, chemistry, electricity and other fields for students 4 to 14. Call (213) 744-7444 or (213) 744-7440.

* The Los Angeles Zoo will sponsor Summer Zoo Camp for children in first through sixth grades July 10 through Aug. 18. Each one-week session will focus on birds or endangered species and includes animal tours and other activities. Call (213) 666-4650, Ext. 5.

* Placerita Canyon Nature Center in Newhall will offer its Summer Nature Camp ’95 program for children ages 6 to 12, July 10 through Aug. 3. Each session runs Monday through Thursday from 9 a.m. to 1 p.m. Call (805) 259-7721, Saturday, Sunday or Monday.

* “Science at the Seashore” workshops will be offered by the Cabrillo Marine Aquarium for children 3 to 5, and in first grade through high school, beginning July 6. Hands-on activities will include using microscopes, exploring coastal and marine habitats and handling marine animals. Call (310) 548-7563.

* The Friends of Madrona Marsh will sponsor a Summer Science Camp for children in third grade and above beginning July 19. Four half-day workshops will explore snails, snakes, beetles and spiders. Call (310) 782-3989 or (310) 32-MARSH.

* The Santa Barbara Botanic Garden will host summer programs beginning July 17. Preschoolers will learn about plants on five consecutive Tuesday mornings beginning July 25. Children 6 to 9 can become “Nature Explorers,” in two sessions beginning July 17 and Aug. 7. Call (805) 682-4726, Ext. 102.

ASTRONOMY

* Reuben H. Fleet Space Theater astronomer Dennis Mammana will explain what will be visible in the night sky in 1995, at 7 p.m. Wednesday at the Space Theater in Balboa Park, San Diego. After the lecture, view the real sky through telescopes. Cost is $3 for adults and $1.75 for juniors ages 5-15. Call (619) 238-1233.

* “Cataclysmic Variables and Dwarf Novae” will be discussed at the monthly meeting of the Western Observatorium at 8 p.m. July 7 in the Tanglewood Recreation Center, Cypress. Call (714) 220-1310.

MARINE LIFE

* A Harbor cruise to introduce adults and children to the marine wildlife and history of Dana Point will be held from 7 to 8:30 p.m. Thursday starting from the Orange County Marine Institute, 24200 Dana Point Harbor Drive. Cost is $11 for adults and $8 for children. For reservations, call (714) 496-2274.

* A 1 1/2-hour tide pool exploration program will be held from noon to 1:30 p.m. Saturday at the Orange County Marine Institute, 24200 Dana Point Harbor Drive. Call (714) 496-2274 for reservations.