In contrast, a national study in 2000 found an average of 125 minutes of science instruction in elementary classrooms.
And 41 percent of Bay Area teachers said they did not feel at least prepared to teach their students science, according to the study done at the Lawrence Hall of Science.
The study may explain California's dismal scores on national science tests. The state ranked fifth lowest in the country in fourth-grade science on the 2005 National Assessment of Educational Progress.
Forty-six percent of Bay Area students scored proficient or above on the fifth-grade California Standards Test in science.
Limited teaching time provides one explanation for students' poor performance.
"If you don't interest kids in the early grades in science, then they're very unlikely to pursue careers in math and science," said lead researcher Rena Dorph. "We've got to do something different."
The study was commissioned by an emerging consortium of Bay Area philanthropic foundations, universities and science museums who wanted to know how best to support science education in the region, said Mark St. John, the president of the educational research firm coordinating the group.
Teachers want to teach science, Dorph said, but they are under pressure from state and federal tests to stress math and reading.
"Part of why we have this problem here is the state and federal policy context that really dictates what happens in schools and classrooms," she said.
In some cases, teachers are mandated to spend specific amounts of time teaching reading and math.
"There never seem to be enough hours or minutes in the day," said Susan Berrington, principal of Grant Elementary School in Richmond.
At Grant, teachers are required to spend about two and a half hours a day on reading and an hour a day on math, said Teacher Elizabeth Bundschu-Mooney. Fitting in time for science is difficult, she said.
"Unless the teacher had a passion for science, they probably weren't doing a lot," Bundschu-Mooney said.
The district had no science curriculum until this year.
Since 2004, the state has required fifth-graders to take a science test and recently adopted curriculum standards.
Bundschu-Mooney said she hopes teachers can come up with 50 minutes each week for science.
At Los Medanos Elementary School in Pittsburg, first-grade teacher Kristi Walton teaches a science lesson for 45 minutes to an hour each week.
On Wednesday, to her students' delight, she pulled out a small plastic case full of worms.
"The kids love science," Walton said. "It's so hands-on."
As part of learning the scientific process, students scribbled down observations ("gooey" and "squishy") and compared worms from the school yard with those that came in a mail order kit.
Sofia Ortiz, 5, said she learned to appreciate the squirmy creatures and their place in the ecosystem.
"I think they're nice," she said. "They want to help us."
With the state now requiring fifth-grade science tests, the school is gearing up to introduce more science concepts at lower levels to build a foundation, said Principal Angela Stevenson.
"We can't expect success if we wait until fifth grade to teach science," Stevenson said.
Like other districts, Pittsburg adopted a new science curriculum this year. Los Medanos elementary is turning one room into a science lab.
In Martinez, Marj Pampe, principal of John Swett Elementary School, said her teachers are able to make time for science. It's difficult to figure out how much time students spend each week on science because it's mixed in with reading and math, she said.
"Science can be a way to hook many of our students into our curriculum," Pampe said. "Science becomes part of the reading and the math."
Shirley Dang contributed to this story. Reach Paul Thissen at 925-943-8163 or email@example.com.
To see a video about the Bay Area science education study, visit http://www.youtube.com/watch?v=GqZUjR-Ex34