The teacher had a geology question for sixth-graders at Phoenix Collegiate Academy.
She asked Thursday morning if anybody could explain a "divergent boundary," a principle in plate tectonics.
Noemi raised her hand and answered: "It's when two plates move away from each other."
It seemed a fitting description for what is happening in her life.
In the fall, Noemi's friends and classmates will move in one direction and she will move in another.
Noemi was born in Arizona and is a legal resident, but her parents are not. As pressure on illegal immigrants rises, her parents have decided they can't stay in Arizona.
Sometime before school begins again in August, they will move to New Mexico.
The last day of school is typically one of joy. This year is more complicated.
The passage of Senate Bill 1070, which makes it a state crime to be in the country illegally, has raised anxiety among immigrant families. And, as the school year ends, more children are realizing they won't be coming back.
Moving to Mexico
Francisco's last day in the Creighton School District was Thursday. His last day in the United States will be sometime in late June. His family is moving to Guadalajara, Mexico.
"It's been a sad day," Francisco said. "Last year, the last day of school was fun. Not this year."
Francisco, 12, his older brother and younger sister were born in Phoenix. His brother is finishing his freshman year at Arcadia High School.
The Arizona Republic is not using their last names to protect their identities.
But now, they are moving to where his parents moved from 15 years ago.
"It's hard to say goodbye to people. These are my best friends," Francisco said. "I'm going to be leaving to Mexico. It's a big change, but it's part of life."
Rosemary Agneessens, principal at Creighton Elementary School, has been writing letters of introduction for students like Francisco who may need them at new schools.
"I've got 50 families with a story like that," she said.
Francisco's parents, Juan and Maria, are confident their son will be able to make the adjustments in school. Juan has been using the Internet to check test scores at different schools in Guadalajara.
But they are worried about him leaving his friends. Francisco is a quiet, shy boy. He has two best friends, his classmates Ricardo and Jose.
"They understand, but they are sort of (quiet) like me," Francisco said. "The three of us have been best friends for as long as I can remember."
Juan and Maria are aware of the irony of their decision. They moved to this country, in part, so their children could have a better life. Now, they are taking them from the only country they have ever known.
"But there are not any other options," Maria, crying, said in Spanish. "We came together as a family and talked. And my sons told me they would not want to see me arrested."
Moving out of state
It's hard for a sixth-grader to be stoic when grown-up events like a new state law seem to be taking away your friends.
"I want to tell her mom not to move," Estephania de la Cruz said while hugging Noemi after science class at their south Phoenix charter school. "She's so kind and nice, she's like an angel."
Noemi, her brother and their parents don't want to move, but Noemi's mother, Luz Maria, said the economy and political climate are forcing her.
Both parents fear arrest and deportation.
When business slowed, Luz Maria lost her job at a bakery where she worked for nine years, and her husband's tow-truck business has been waning.
"It's hard right now, and it's going to get worse," Luz Maria said. "It's hard for me, but it's much harder because it affects my children."
Noemi cries every time she talks about leaving Phoenix. She will miss her friends, she said, and her school and her teachers. But mostly her friends.
Today, the last day of school, will be particularly dramatic. "I love my friends. I've been friends with Jacquelin my whole life."
The two of them sat on the floor in the hallway at Phoenix Collegiate Academy.
Jacquelin's mother used to watch Noemi when the girls were just toddlers.
They said they will miss talking. And playing tag. And fixing each other's hair.
"When we were kids, we used to do each other's hair a lot," Jacquelin said. "Now, I won't have anybody to do my hair."