SAN JOSE -- What do earthworms prefer -- apples, potatoes or oats? How do you make a sound wave visible to the naked eye? Can a coffee can help measure the calories in a cashew?

In a tech mecca like Silicon Valley, it's not all that surprising some teenagers have a burning interest in the answers. But in East San Jose, schools don't offer any lab sciences until ninth grade, unlike those in Cupertino and other affluent areas -- a gap Saturday's science fair aimed to help fill.

Dubbed sciencepalooza!, the 15th annual event brought droves of East Side Union High School students to an exhibit hall at the Santa Clara County Fairgrounds. In braces and skinny jeans, they set up cardboard displays and waited nervously to tell roving judges about their projects.

"Sciencepalooza! can be a trajectory-changing experience,'' said Paul Kilkenny, the district's science coordinator. "It can end up being a huge change in self-concept.''

Students gain experience in meeting deadlines, coming up with ideas or replicating tried-and-true experiments, doing research, and analyzing and communicating the results. The event is primarily sponsored by the Synopsys Outreach Foundation, an offshoot of the integrated chip design company.

Cordell Wagner, 16, and Darius Scott, 17, wanted to know if earthworms prefer one food over another. Their conclusion:

"Oats,'' Cordell said, "probably because they're easier to break down than apples or potatoes.''

Ellesia Janto, 16, measured the calories in cashews, peanuts and marshmallows by burning the items in homemade calorimeters made out of different-sized coffee cans, concluding that the 10-centimeter can was best.

Brittany Blevins, 17, won an award for the most ingenious project with "Waves on Fire,'' a replication of a famous physics experiment. Using propane and a long silver perforated tube, she showed what acoustic standing waves look like.

"You're pretty much able to see sound,'' she said enthusiastically.

Deciding on a career won't be too difficult for Brittany. Though she loves children and said she wouldn't mind being a kindergarten teacher, she also inherited her father's interest in engineering.

"I have his little tinkering brain,'' Brittany said.

Contact Tracey Kaplan at 408-278-3482. Follow her at Twitter.com/tkaplanreport