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The Bohr’d atom

Happy 4th of July everyone.

A bit of interesting news came out of A Rice University recently with the announcement that a research team had created a Brobdingnagian atom that’s about a millimeter in size.

Not only is the atom huge but its size caused the atom to ironically resemble the somewhat antiquated image of an atom envisaged by Danish physicist Neils Bohr in 1913 in which electrons were imagined as orbiting the atomic nucleus like a little planetary system.

Using lasers and electric fields, the research team at Rice ballooned potassium atoms until one electron was orbiting at such a distance that it bridged the gap between the microscale and the macroscale.

Lead researcher Barry Dunning and Helen Worden Professor of Physics and Astronomy stated that:

“In a sufficiently large system, the quantum effects at the atomic scale can transition into the classical mechanics found in Bohr’s model, Using highly excited Rydberg atoms and a series of pulsed electric fields, we were able to manipulate the electron motion and create circular, planet-like states.”

I remember the day I learned that the planetary image of atoms was incorrect. It was a pretty bizarre feeling but it also was my first foray into the wonderful world of quantum weirdness.

Even if the planetary atomic model isn’t strictly accurate looking through our modern perspective of atomic orbitals, it was the first successful theoretical model of the atom. Scientists of that time were puzzled that when elements like hydrogen emit light, it wasn’t a nice rainbow of colors but discrete lines of color or wavelengths. Why did atoms emit these spectral lines? Bohr’s main radical idea was that electrons could only be in specific clearly defined orbits around a nucleus. All other orbits between these allowed orbits were verboten. Bohr’s second breakthrough idea was that electrons leaped from one orbit to another, releasing or absorbing energy as they did so. This neatly explained how the spectral lines were produced.


The little bit of quantum weirdness in this process that always intrigued me was the idea that electrons apparently went from one orbit to another without really existing in between. This of course leads into one of my pet peeve expressions…A “Quantum Leap“. Casually, this means a huge increase….like “a quantum leap in technological sophistication.”

In physics it means a very small jump from one electron energy level to another. I love expressions derived from science that completely reverse the original meaning.


The domino effect of understanding that resulted from Bohr’s insight helped open new eyes onto the universe and created tools with awesome utility. Astronomical spectroscopy tells us the chemical composition and the physical properties of objects in the sky and also what their velocities are. Lasers can also be traced back to Bohr since they operate by exciting electrons into high orbits which then release their coherent light when they drop down to lower orbits.

Bohr’s atomic insights gave scientists a much deeper understanding of the physical and chemical properties of atoms and paved the way for the even deeper understanding that scientists have today. I wonder what further secrets are waiting to be revealed to future generations of scientists.

Hopefully my treatment of this topic here sparked your interest by more that just a quantum leap

p.s. My historical condolences to poor Austrian physicist Arthur Erich Haas who apparently anticipated Bohr’s breakthrough idea of quantized electron energy levels by three years only to have his ideas laughed at.

p.p.s. Happy birthday to my dizygotic twin Joe 🙂

8 comments to The Bohr’d atom

  • nowoo

    “I love expressions derived from science that completely reverse the original meaning.”

    Phil Plait points out the example of “meteoric rise” in his book Bad Astronomy.

  • Sam

    Brobdingnagian <– What a great word!

    If it ‘bridged the gap from microscopic to macroscopic’, does that mean we could actually see it (using a microscope)? Or is that macroscopic in a kind of abstract sense? What would it look like!?

  • esmitt

    The whole shift of electron orbits causing the emmision of photons in the visible and invisible spectra is what freaks me out on a daily basis. Looking at the Nitrogen sky, contemplating sunsreens and even looking at the red traffic light gives me a little titter of ‘geez that is cool’. I never did really appreciate it back in university physics, but it leaves me truly agog…why the heck to people have to make up stuff when we have such seriously bizarre stuff in our own reality.

    Thanks Bob.

  • Quantum Leap might sound illogical to a student of physics. But quantum has several meanings.
    While in physics it generally means the smallest measurable amount, outside of the science realm it simply means an amount or a specified portion, it being a derivative of the word quantity.
    Therefore a change in value of an object from where something might be measured in inches to where it must be measured in miles could rightly be called a Quantum Leap although it has nothing to do with quantum mechanics.

    In your article, describing a “quantum leap” in atom sizes, nicely clashes the two definitions.

  • Sam, It might have been more accurate to say that the electron bridged the gap from the quantum to the classical.

    I don’t think a normal microscope could see it but whatever device they used in the top picture above, that’s what it looks like with current technology.

  • Sam

    Thanks Bob…
    I did wonder how a single electron wave thing in a high energy shell could be visible.
    I have some knowledge at least electrons getting excited and quantum leaps from physics A levels and books, so it seemed a silly question when I was typing it, but the word ‘macroscopic’ threw me.

  • dcardani

    For a second, I thought you were describing the element “jumbonium,” which you can see described here:


  • John Powell

    It’s not just scientific terms that get mixed up in common usage. Take the word ‘decimate’ – it literally means to reduce by one-tenth. In common usage today it means utter destruction. Originally it referred to the Roman military practice of executing one-tenth of the men in a mutinous legion.

    Don’t get me started on on the words ‘liberal’ and ‘conservative’… the meanings of these words are flip-flopped and twisted seemingly with every generation in the US.

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