(CNN) -- Science teachers consider Pluto's flunking out of planet status a plus rather than a minus.
"It's exciting. It's a chance to teach kids that this is the nature of science. Things are always changing," said Rich Hogen, who taught fourth grade for 32 years in the Arizona school system.
At the beginning of the week, it looked as if Pluto would be spared the subtraction as the International Astronomical Union considered increasing the number of planets to 12.
But Thursday's vote reversed course, categorizing Pluto and two of the planet hopefuls, Ceres and Xena, as dwarf planets.
"I think it would have been more difficult had they added more," Hogen said. "There's a lot of research out there on the nine planets. They just dropped one."
Instructors who taught for years that our solar system has nine planets will have to spend some time brushing up on the new categories.
"I spent a half-hour poking around in books to get a sense of what definition of a planet has been used in the past and how the proposed changes are taking place," said John Whitsett, who has taught chemistry and physics for more than 30 years.
"It's a chance to start looking at more than just the nine planets," Whitsett said. "What do we mean by a comet? What do we mean by a dwarf planet?"
Whitsett believes the change will focus attention back on science, which he thinks has been relegated to a supporting role in recent years.
"Ever since No Child Left Behind was passed, there's been a tremendous emphasis on reading and math, and as a result, especially in elementary schools, science has taken a back seat," he said.
"What we have is something that's been making a lot of press. Students are going to be asking questions, and I've always found that the best time to teach is when kids are asking questions, " Whitsett said. "Anything that gets kids engaged and thinking about science has got to be a good thing."
Susan Wagner, vice president for exhibits and programs at Adler Planetarium in Chicago, Illinois, said her team has some work to do.
"We will definitely be adjusting our exhibits to reflect this vote," she said. "When our building was created, we originally had eight planets that were placed in the outside façade, because Pluto was not discovered. So it's ironic that we're going back to the eight planets."
Inspiring future explorers
Becky Peltonen, an elementary school teacher in Panama City, Florida, had mixed feelings.
"On one hand, I like for the eight to have exclusivity, because you need to have certain characteristics to be a planet. It shows kids that some things do have to change. We need to teach modern science and use the new definitions," Peltonen said.
"But on the other hand, I'd like to stick with tradition," she said. "Let Pluto be grandfathered in."
Peltonen was disappointed about the astronomical union's about-face on numbers. "I wanted them to add the planets, because I think that would inspire the next generation of explorers that there are things out there to be discovered."
Peltonen, who teaches science to all grades at Oscar Patterson Elementary School, had her fifth-graders sing their mnenomic "planets song" after the news of Pluto's downgrade.
"I'm going to have to write a new song!" she said when they finished.
A top science teacher pointed out another change. "Teachers will have to redo their murals," Gerry Wheeler, executive director of the National Science Teachers Association, said.
But, he said, "The opportunity far outweighs the inconveniences of renaming a planet."
Whitsett, who is the president-elect of the NSTA, emphasized that the refigured solar system can energize teaching the true meaning of science.
"It's not a collection of facts. It's a process. It's a way of solving problems. As our understanding of these facts changes, then the science changes a little bit," he said.
Science and understanding change, but this change is not so earth-shattering, he said.
"The solar system right now is exactly like it was 24 hours ago," Whitsett pointed out. "Nothing's changed in that time period -- just the name by which we define each of these things."