Ahmed Mohamed, center, met Kiera Wilmot, right, and her twin Kayla Wilmot, left, at the White House on Monday. (Marie Wilmot)

Ahmed Mohamed, who became an international cause célèbre this fall when he was arrested for bringing a homemade clock to his Texas school, was one of hundreds of students who visited the White House on Monday. And he wasn’t the only one who had once been hauled off in handcuffs for dabbling in science.

Two years ago, a Florida honors student who was curious about chemical reactions mixed aluminum foil and toilet bowl cleaner in a bottle, resulting in a small explosion that damaged no property and injured no one. Kiera Wilmot, then 16, was arrested, expelled and charged with two felonies because of that science project gone awry.

Both of their stories have come to serve as symbols of what critics say are harsh school discipline tactics that disproportionately affect minority students, and that the Obama administration has pressed to change.

[White House hosts Texas student arrested for homemade clock]

When the two crossed paths Monday on the way into Astronomy Night at the White House, they didn’t have much time to talk, Kiera said. But they recognized each other, and they stopped to record the moment in a snapshot.

“He was like, ‘You’re the Florida teen!’ And I was like, ‘You’re Ahmed!'” Kiera said Tuesday. “When I first heard his story, I was like how could this happen again?”

President Obama didn’t mention either teen by name in his remarks at the event, which was meant to encourage young people to pursue careers in science and engineering. But he said adults need to be careful to nurture scientific creativity — not snuff it out.

“We need to inspire more young people to ask about the stars, and begin that lifetime quest to become the next great scientist, or inventor, or engineer, or astronaut,” Obama said. “And we have to watch for, and cultivate, and encourage those glimmers of curiosity and possibility, and not suppress them, not squelch them — because not only are the young people’s futures at stake, but our own is at stake.

Public outcry in response to the arrests of Ahmed and Kiera helped persuade authorities to drop the charges against both teens. Ahmed has spent the last month in a media spotlight as he’s visited companies like Google and Facebook and even traveled to Sudan to meet President Omar al-Bashir.

[‘Clock kid’ Ahmed Mohamed and his family will move to Qatar]

Meanwhile Kiera — who was ultimately allowed to graduate from her high school, after her mother spent thousands on legal fees — has been quietly working toward a mechanical engineering degree at Florida Polytechnic University.

Their stories ended happily thanks in part to an outpouring of Twitter rage on their behalf, but many young people who are shunted toward the so-called school-to-prison pipeline are not so lucky, advocates say. Suspensions and expulsions, even for minor offenses, are linked to higher dropout rates and a greater likelihood of involvement with the criminal justice system.

“It really highlights what we are seeing nationwide, and that is there is a school discipline crisis,” said Thena Robinson Mock of the Advancement Project, a national civil rights groups that has helped lead the charge against zero-tolerance discipline policies.

Kiera’s story in particular shines a light on the increasing numbers of black girls who are being shunted into the criminal justice system, an often overlooked trend, Mock said. Black girls were six times more likely than white girls to be suspended from the nation’s public schools in 2012, according to federal data.

Did race play a role in Kiera’s arrest? She has no doubt. “With those statistics, there’s no denying it,” she said.