When a visitor to Kimber Hershberger’s school offered a handshake, she declined it. She wasn’t being unfriendly. “Sorry, I have rock dust on my hands,” she said, smiling and holding them out for inspection. Her chalky mitts came from pounding sediments for models of conglomerate rocks, just one of the many hands-on lessons the innovative science teacher uses to help students unlock secrets of the natural world.

Hershberger, a third-grade teacher at Radio Park Elementary School with more than 30 years in education, loves showing children the scientific process: making a “claim,” gathering “evidence” and then forming “reasoning.”

“For me, it’s taking that natural curiosity and giving meaning to that,” she said.

By early next year, she could be recognized nationally for her classroom talents. She’s among the 2012 nominations under consideration for a Presidential Award for Excellence in Mathematics and Science Teaching, the highest recognition given to math and science teachers for outstanding instruction.

Since the award’s inception in 1983, more than 4,100 teachers have received the honor. It comes with a $10,000 prize from the National Science Foundation.

But Hershberger would rather talk about an achievement in hand — her recently published professional development book “What’s Your Evidence? Engaging K-5 Students in Constructing Explanations in Science.” She co-wrote it with Carla Zembal-Saul, a Penn State science education professor, and Katherine McNeil, a Boston College assistant science education professor.

One chapter covers “content storylines,” the heart of Hershberger’s philosophy. She follows its tenet of creating a “big picture” by sequencing science ideas to build on each other.

In that respect, when explaining simple machines or the solar system, she becomes part English teacher.

“I’m teaching a story when I’m teaching science,” she said.

With a unit on rocks and minerals, for example, students might follow a storyline like this: A test for minerals leads to the point that granite contains minerals, followed by teaching that rocks are formed by minerals. Then comes a deeper exploration of minerals as basic components. To learn about sedimentary rocks, students first make food layer models. Next, they create their own rocks out of clay and sediment. Lastly, they examine actual rocks under microscopes. “I believe my job is to empower my students to think, to do research, to make connections,” she said. They then get to report their “evidence” and “reasoning” in their own scientific journals, complete with cartoon characters such as “Crazy Crystal” and “Minerva Mineral.” “It’s helped them be more invested in their journals,” Hershberger said. Her own story started in Martinsburg, Blair County, where the education bug first bit her during visits to her mother’s elementary school classroom. At Juniata College, an independent study project — a multistate tour of progressive elementary schools — left an impression. “It was very inspiring to me to visit places where kids had ownership in what they were doing,” she said. To her elementary education degree she added a master’s in science education from Penn State. At Radio Park since 1985, she has taught professional development at the university, given presentations at the National Science Teachers Association annual conferences, and co-written several articles for NSTA journals. Her evidence of success comes from moments like when an electricity lesson excited a student. “He said, ‘Now, I finally understand how a flashlight works,’ ” Hershberger said. “That was pretty cool.”