A glossy booklet with an intriguing title recently turned up in Patrick Engleman's mailbox. "Why Scientists Disagree About Global Warming," it proclaimed.

A cover letter packaged with the book told recipients to "consider the possibility that the science in fact is not 'settled'" when it comes to the causes of climate change. Further, "students would be better served by letting them know a vibrant debate is taking place among scientists on how big the human impact on climate is, and whether or not we should be worried about it."

The letter was signed by Lennie Jarratt of the Heartland Institute, a conservative think tank that disputes the mainstream scientific theory that human-caused climate change poses a serious planetary threat.

The surprise here isn't the content, but rather the audience.

Engleman is a ninth-grade physics and chemistry teacher in Montgomery County, Pennsylvania, and he is one of thousands of teachers who've received this primer on climate science. The Heartland Institute said it's sending one of these books to every public school and college science teacher in the country — about 300,000 copies, according to spokesman Jim Lakely.

When Engleman received his copy, he was outraged. As someone who agrees with prevailing scientific thought on climate change and its causes, Engleman stewed as he thought about how this information might be deployed in other science classrooms.

"It's not that I'm the best science teacher in the world. It's not that I know everything," he said. "It's that someone's going to get this and think this is real."

'Muddying the waters'

The Heartland Institute's guerrilla lobbying effort illustrates the predicament today's science teachers face. Like all of us, science teachers inhabit a world awash in information and riven by stark political divides. Amid the noise, they're supposed to teach something that at least approximates objective truth.

"Social media has changed what information is considered valid or reliable," said Nancy Songer, a science education researcher and the dean of the School of Education at Drexel University. "I think it's muddying the waters in a way that's making it more difficult for science teachers actually to be able to emphasize, for example, a science approach in the classroom."

Teaching science has never been a totally apolitical task — just ask anyone who has ever taught the theory of evolution. But today, experts say, it's especially tough.

In essence, said Charles "Andy" Anderson, a science education professor at Michigan State University, science teachers find themselves squeezed into the same box as journalists and judges. All are cast as objective arbiters of information — an increasingly untenable position in a world flooded with "fake news" and "alternative facts."

"Everybody who is supposed to exert authority in some way is dealing with this kind of decay of our institutions for establishing and maintaining a sort of moral authority and intellectual authority," said Anderson.

This poses a particular challenge to those who are training the next generation of science teachers, folks like Susan Yoon, a professor at the University of Pennsylvania's Graduate School of Education.

susan yoonSusan Yoon, a professor at the University of Pennsylvania Graduate School of Education, teaches a course for future science teachers. (Avi Wolfman-Arent/WHYY)

Yoon teaches a specialty course called "Advanced Methods in Middle and High School Science," and her seminar is a small laboratory for the kinds of challenges science teachers face.

"I think it's harder — with this information explosion — to know how to negotiate through all this information that is available to you, both for the teacher and the student," she said.

An Earth-shattering moment

A recent Wednesday class provides one particularly trenchant example.

To start the class, student teacher Nick Gurol detailed a jarring episode where a number of students told him the Earth was flat. The students, all seventh-graders, had picked up this peculiar notion from basketball star Kyrie Irving, who said the same thing on a podcast hosted by two of his Cleveland Cavalier teammates.

Now imagine being a rookie science teacher whose task is to offer up an education to a bunch of kids who really like Kyrie Irving.

"Immediately, I start to panic," Gurol said. "How have I failed these kids so badly they think the Earth is flat just because a basketball player says it?"

He tells his professor and his peers he tried showing the students a YouTube video aimed at countering flat-Earthers. He tried reasoning with the the students. None of it worked.

"What do I do," he asked his classmates. "They're not listening to facts. They think that I'm part of this larger conspiracy of being a round-Earther. That's definitely hard for me because it feels like science isn't real to them."

classA course called "Advanced Methods in Middle and High School Science" confronts the challenges posed by "fake news." (Avi Wolfman-Arent/WHYY)

Yoon and the rest of the student-teachers dissected the problem, starting with some specific remedies, but eventually leading to a fundamental question for today's science teachers.

"Isn't it our role as science teachers to teach the truth?" Yoon said.

In other words, is it their job to correct misinformation on the shape or temperature of the Earth? Or is it more important to teach students how to think scientifically so that they can become better consumers of information?

Classmate Allison Sparrow said it's the former — science classrooms have to be bulwarks of scientific authority in a fact-starved world.

"I mean if you're not doing it in the science classroom, it's not going to happen at all," she said.

But you can't really tell students what to believe, countered Rebecca Raso. You've got to present the evidence and let them evaluate it.

"That way it's not just we're telling them that, but they can come to that conclusion themselves, which kind of gives them a better chance of actually believing it," Raso explained.

Yoon told her student-teachers that, as hard as they try, science teachers aren't likely to change a student's misconceptions just by correcting them. Society's best shot for an informed citizenry, she argued, would be giving students the tools to think like a scientist. Teach them to gather evidence, check sources, deduce, hypothesize, and synthesize results, she advised.

Nick Gurol agreed. Perhaps the best way to fix his flat-earther problem is to give his students the best tools and let them explore.

"They can come to that conclusion themselves, which kind of gives them a better chance of actually believing it," he says.

Ever the teacher, though, Yoon throws in one more question.

"What if they don't come to that conclusion?" she said.

Some students advised to make up their own minds

This may sound like an academic question, but it has real-world implications.

Take the topic of climate change. Nearly one in three Americans don't think global warming is caused by human activity, according to a recent Gallup Poll. How the nation's science teachers approach the subject could well influence whether that number goes up or down.

A 2016 study found that about a third of the nation's science teachers also teach their students that climate change may be the result of natural causes, not human intervention. And even those teachers who do believe the mainstream science may not be so willing to pass that view along to their students.

"Teachers have conflicting pulls on them," said study co-author Eric Plutzer, a political science professor at Penn State University. "On the one hand, science teachers want to convey the best science possible. On the other hand, they have a strong confidence in their students' ability to learn by exploring things on their own."

Complicating matters is the fact that climate change is a relatively new science that many current teachers didn't learn while they were in school. Although the subject is increasingly a part of official scientific standards in many states, Pennsylvania's standards, for instance, do not directly address climate change, according to Cheryl Bates-Lee, a spokeswoman with the Pennsylvania Department of Education.

Perhaps it's not surprising then that Plutzer found more than half of science teachers encourage students "to come to their own conclusions" on climate change.

"We wouldn't ever expect teachers to do that with other topics," he said "For example, we wouldn't expect teachers to say, 'Come to your own conclusions on plate tectonics.'"

Then again, even the most mundane scientific topics may no longer be safe from the muddied waters of modern life. After all, Nick Gurol's confrontation with a group of middle school flat-Earthers began with a lesson on — what else — plate tectonics.