"Mrs. Judd? How come they flew into the towers?"
Joan Judd spent her summer vacation preparing for questions like that from her fourth-grade class in Milford, N.Y.
"A few of them were born in 2001. Most of them were born in 2002. They were not around for 9/11," said Judd, "When I prepared my lesson, I realized that I was talking about the Twin Towers and fourth-graders might not even know what the Twin Towers are."
Judd teaches at an elementary school in upstate New York, which, like most of the country, has no set standard on how to teach the terror attacks of 9/11.
"You have to assume they know nothing," says Richard Schude, an 11th grade history teacher at Franklin Delano Roosevelt High School in Brooklyn.
It's a touchy subject, and it is largely up to individual teachers to decide whether they want to touch it at all. Teachers like Judd and Schude spend their own time and money researching the facts and preparing their own lesson plans. Many others avoid it for fear of saying the wrong thing.
"I don't know how to approach it without saying, 'These monsters attacked us'," said a grade school teacher who didn't want to be identified. "There has to be another way to say it."
"There is. Survival," former NYC High School Principal Ada Dolch said.
Dolch had to evacuate her high school in the shadows of the Twin Towers on 9/11, taking her hundreds of students through the streets to safety in Battery Park. Dolch now volunteers for the Tribute WTC Visitors Center. She tells her personal story in the Tribute Center's online toolkit for teachers, appears in classrooms, and takes educators on field trips to the World Trade Center to help them gain a better personal understanding of the attacks.
"It's a scary topic. It's one that you want to be sensitive about," Dolch said, "You want to be careful what message you portray, especially since it's a raw issue."
It's a raw issue because 10 years later 9/11 is transitioning from a current event to part of American history.
New York State Sen. Jack Martins says teachers shouldn't have to seek out the best ways to teach on their own time and dime.
"I think we should have a set curriculum and the lessons should be taught in a way that is uniform and not subject to each individual teacher's preferences," said Martins.
Martins is proposing a bill that would make teaching 9/11 required by law in New York State. Lawmakers in Albany are expected to vote on it in January. Right now, 20 other states mention the terror attacks in their standards, some even provide lesson plans, but their teachers are not legally required to follow them or even teach it at all.
Judd says having a set standard would be helpful. But Schude isn’t so sure.
"I think teachers should be given some sort of a guide, I don't think they should be spoon-fed,” said Schude. “Every teacher has their own demographics that they're dealing with, and I think that point needs to be made."
Parents are largely supportive of teaching 9/11 in schools. They just want to make sure their kids are old enough to handle it.
"If they're too young and they're not going to be able to grasp what it means," said parent Koby Annan. "Really, there's no point in showing them that kind of tragedy."