It's third period at Lawrence Middle School in Chatsworth, and social studies teacher Brent Smiley has exactly 50 minutes to cover 9/11.

He asks for memories; few of the eighth-graders have any since they were just 2 or 3 years old when the terrorists launched their attacks. He tells them Saddam Hussein was a thug who gassed his own people and that the Taliban oppresses girls. He mentions the heroes of Flight 93. He says the attacks had nothing to do with Islam any more than the Ku Klux Klan reflected Christianity. He stresses: "Not only do we have the ability to fix what's wrong, I would argue we have an obligation ... if not us, who? If not now, when?"

Lyndia Free, 13, raises her hand. "Have we ever been told what was their motive?"

Full coverage: A decade after 9/11

Smiley glances at the clock. "Nothing I can convey in three minutes," he says.

Time's up. The annual lesson about 9/11 is over. And so it goes in many classrooms around the country. A decade after the Sept. 11 attacks transformed America in so many ways, numerous students say they still know very little about those events. And many educators lament that they lack the time, expertise, resources — and in some cases, the nerve — to tackle the huge, complex and controversial subject in a meaningful way.

Many organizations, including the Smithsonian Institution, the California Department of Education and the Los Angeles Unified School District, have compiled repositories of teaching resources to address key questions about the event: what happened and why, how the attacks changed America and lessons learned. One of the Smithsonian websites includes, among many other things, links to suggested lesson plans for all ages: from creating flag murals for kindergartners to exploring Islamic extremism and Afghan culture for high school students.

But at least in California, many teachers say they simply don't have time to use much, if any, of these materials because they are urged to focus on the state's academic standards, which are linked to high-stakes student achievement tests. Further, those standards don't include 9/11 — or anything much beyond 1980, according to Avi Black, president of the California Council for the Social Studies.

"How can you possibly live in the current world and not know about 9/11?" Black said. "But there isn't much teaching on 9/11 … because of pressure for a lock-step adherence to the standards."

Smiley, for instance, said L.A. Unified issued a memo on the day of the attacks instructing teachers to turn off classroom television sets and return to the curriculum. He ignored the directive then, he said, but he can't afford to spend the time required to thoroughly teach about Sept. 11 when he has to get through centuries of American history, from the early European settlers to the Civil War and Reconstruction.

(A spokesman for L.A. Unified said the nation's second-largest school system has no policy on whether or how to teach about 9/11. Several schools are planning memorials Monday.)

Some say teachers shrink from the topic because of sensitivities over religion, war and politics. "Teachers are cautioned over and over again not to talk about religion," said Danford Schar, principal at Lawrence. "Some have interpreted that in a broader sense that we shouldn't be talking about religion at all, and that creates hesitation to say anything about those of the Islamic faith."

That caution, however, draws criticism from others dissatisfied by what they view as a one-sided focus on peace, tolerance and multiculturalism to the exclusion of hard lessons about safeguarding American values in a menacing world.

"Our country has enemies who hate what America stands for," said Michael Petrilli of the Thomas B. Fordham Institute, a Washington-based education policy group that recently issued a report on teaching about 9/11. "Kids should know something about radical Islam."

But that, teachers say, is one of many complex topics surrounding 9/11 that would require extensive training.

Still, many teachers say 9/11 is too important not to try to address in some way — especially since most students today were either not born or were too young to remember the attacks first-hand.

Black suggests that teachers be trained to weave 9/11 lessons into their required curriculum. As an example, he says, the Alien and Sedition Acts of 1798, part of the eighth-grade social studies standards, could be related to the Patriot Act adopted after 9/11 and the ensuing debates over national security versus civil liberties.

At Crenshaw High School, English teacher Van To assigns poetry and narratives about the victims and survivors and plans to require students to interview someone about their personal memories of the attacks. She also assigns "The Kite Runner," a popular novel about an Afghan boy, to teach students about Afghanistan and the differences among Muslims.

Eddie Grigorian at Chatsworth High School plans to show video clips of both 9/11 and Pearl Harbor to draw similarities, and he will ask students to write about their feelings and discuss them.

At Sun Valley Middle School, social studies teacher Stephen Franklin led efforts to construct an elaborate, multimedia memorial exhibit to expand his students' limited knowledge about 9/11. Each year, he said he sees students' knowledge shrink as the attacks grow more distant.

"They know airplanes flew into buildings and 'the terrorists' want to kill us, but they don't know why or who they are," said Franklin, who also leads an annual student trip to ground zero in New York City.

The exhibit, which all students will visit Monday and is open to the public, includes 9/11 news coverage, then-President Bush's speeches about it, 8-foot models of the Twin Towers, a giant paper flag with the nearly 3,000 victims' names handwritten on it and other items.

"9/11 altered the world with such an incredible impact," he said. "Kids need to know this stuff."

Many students agree. Lawrence eighth-grader Myahn Haroush said she would prefer to spend more time understanding this key event — which she says has already sparked family arguments over Islam — than learning about ancient civilizations. Lyndia Free says she wants answers to many questions about the terrorists' connection to Islam and the link between 9/11 and the wars in Iraq and Afghanistan, to name just a few.

"I've always been so confused — it's still such a blur," Lyndia said. "I really want to know the truth."

Full coverage: A decade after 9/11

teresa.watanabe@latimes.com