Way back in 1913, everyone hailed Niels Bohr’s new model of the atom. It pictured electrons orbiting a central nucleus like planets orbit the sun, and it’s still the most common picture of the atom today. You can find it on countless science t-shirts and in TV shows like The Big Bang Theory, but here’s a reality check: scientists replaced it way back in the 1920’s.
But before we start pushing for more accuracy in our media (and I think we should), this old model still has something to teach us about how scientists today tackle big problems.
Physics was changing fast at the start of the 20th century, when a young Niels Bohr was out to prove his worth. In college, he worked obsessively in a competition meant for mature scientists and won its gold medal. By the time he earned his Ph.D., Bohr was a force to be reckoned with. He landed a job with a Nobel Prize-winning professor. When that relationship quickly soured, he simply arranged to work with another Nobel laureate by the name of Ernest Rutherford. In 1912, he fatefully took on his mentor’s old project: the structure of the atom.
Only a few years earlier, Rutherford had discovered roughly how an atom was built, but his model couldn’t explain how it worked, much like a sketch of a bike without its gears. Amazingly, it only took Bohr a year to breathe life into his boss’s model and make it his own. Among its successes, Bohr’s model of hydrogen explained why hydrogen lamps (picture neon signs) glow red instead of another color. In other words, he’d taken that sketch of a bike and painstakingly drawn in working gears. Not everyone had been on board with Rutherford’s model, but Bohr’s hard work cemented its place in science. The Norwegian Nobel Committee moved fast (for them!) to award Bohr the prize in physics in 1922.
But all that success doesn’t mean the model was perfect. It got hydrogen right, but it failed miserably at describing the other elements. Bohr and others spent the 1910’s and 1920’s debating how to make the model better. One scientist got better results when he tried oval-shaped orbits, which quickly became the norm. Another scientist came up with the idea that two electrons could share an orbit, an idea that ended up outliving the Bohr model itself.
Unfortunately, not all of these issues could be fixed. Just four years after the Nobel Prize, a huge sea change in physics made Bohr’s model obsolete. The new model, called quantum mechanics, took a page from Bohr but took it to a whole new level. It explains the lives of atoms much better than Bohr’s model does, and science has never turned back.
And yet it’s Bohr’s model of the atom that people recognize most today. Image search for “the atom” online, and the vast majority of results show his atomic solar system. Nearly no results show the strange, balloon-like shapes that have accurately described the deepest workings of chemistry for nearly a century.
So why has the Bohr atom stayed around? “It gives us a good place to start the conversation about the composition of the atom,” says high school chemistry teacher Dr. Jason Dyke. This is tricky material, and Bohr’s picture of the atom is simple and works well enough, so it’s a good introduction. When it comes to the more modern models, Dyke says “we tend to only touch on those briefly and leave it behind” because there just isn’t the time. After school, people tend to remember the image that they spent more time with.
However, Dyke says that replacing the Bohr model in his curriculum would be difficult, and not just because it’s easier to learn. He says he uses it to teach students that “even [information] that is somewhat wrong can be enormously useful for […] changing the thought process in a certain field.” Indeed, it may seem unlucky to give a Nobel Prize to a model that was quickly replaced, but it celebrates the great step forward that science as a conversation took. While using Bohr’s flawed model, he and other scientists came up with ideas that have held strong into the 21st century.
Science deniers often use the changing models in science to cast doubt on what we know, but Bohr’s story teaches us to stand firm. Just like how Bohr’s ill-fated model correctly explained hydrogen’s glow, today’s imperfect models in climate science and pharmacology can help us understand climate change and make better medicine. The way that we slowly improve imperfect models lets us tackle huge, tough problems bit by bit, and it works. And when we do have to update our understanding, it certainly doesn’t mean we have to throw out the baby with the bathwater.
I’ll admit that I get tempted to explain “the real science” when I see a Bohr atom, but this can be about more than pedantically correcting t-shirts. It’s an opportunity to talk about the evolving models and debates that drive forward our understanding of the world. Next time you see the Bohr atom in the wild, I hope you’ll reflect on that, too.