Brontosaurus is a dinosaur
I’m not sure if it was elementary school science classes or Fred Flintstone’s Brontosaurus burgers that made the giant herbivore one of the most popular dinosaurs for me as a child. But for more than a century, Brontosaurus was not considered a true dinosaur: Paleontologist Othniel Charles Marsh named the first dinosaur fossil in 1879, two years after he identified a similar specimen and called it Apatosaurus. In 1903, researchers decided that the Brontosaurus fossil was a mislabeled Apatosaurus, and after that, they were all formally called Apatosaurus.
A 2015 report in Scientific American clarified that recent analyzes indicate that the two fossils are distinct enough to warrant separate names of the genes, so Brontosaurus is back (no need to unlearn it!). However, the systematic study of fossils reveals that there were far more types of massive plant-eating dinosaurs known as sauropods than paleontologists had previously imagined.
George Washington didn’t have wooden teeth
He did have serious dental problems (when he gave his first inaugural address in 1789, Washington had only one remaining natural tooth), but Washington never had any teeth made of wood. Instead, they were complex contraptions made of ivory, gold, and lead— some experts think people believed they were made of wood because the ivory had stains.
Washington’s dentures also contained real teeth, perhaps from cows and horses, and definitely from other individuals. He saved some of his own teeth, and one of his books addresses the purchase of nine teeth from African-Americans imprisoned in his plantation, Mount Vernon, according to the estate’s historians.
Although several former schoolchildren feel hurt at the time, Pluto was not the first planet to be demoted— it had already happened to a body called Ceres, which orbits between Mars and Jupiter. Ceres was still considered a planet when it was first discovered in 1801, but over time astronomers learned that it was part of an asteroid belt and that it revoked its planetary status. But the tale doesn’t end there— both Ceres and Pluto came back into a new category in 2006 when the International Astronomical Union named them dwarf planets.