Their space balloon took off Friday morning from the Morgan Territory Regional Preserve in eastern Contra Costa County.
The Bay School of San Francisco's science club placed a high-definition video camera on the balloon, along with other instruments.
"We're hoping this reaches about 100,000 feet in altitude and it will take some data measurements, pressure, internal temperature, external temperature," says Bay School science club member Jesse Greenfield.
"This has been a lot of work. We got to school yesterday at nine and we've been working straight through ? just got a couple of hours of sleep. When they work hard, they learn a lot," says Bay School science teacher Richard Piccioni.
A GPS device indicates the balloon landed in Turlock.