Placeholder Image

Subtitles section Play video

  • Thanks to Google for sponsoring a portion of  this video, for supporting small businesses,  

  • and for helping people find  jobs. More about that at the end.

  • Atomic orbitals have long been a source of  frustration for me. On the one hand, you  

  • have simple cartoon diagrams that make them feel  friendly... but which are so varied and vague they  

  • don't really convey much beyond the basic idea  that atoms have a nucleus and some electrons. Some  

  • people try to take the cartoony diagrams and make  them feel more random, orquantum” – which is an  

  • improvementbut they're still very much just  cartoon stand-ins for the vague idea ofatom”.

  • On the other hand, you have atomic orbitals  depicted as fuzzy clouds or balloons or  

  • rainbow donuts, which are definitely more  technically accurate (or technically inspired),  

  • but none of which feel like they give me a sense  of what's actually going on - like, what does this  

  • blobby thing have to do with orbiting particlesIs the electron inside it? Or on the surface? Why  

  • do some of them have more blobs and others donutsAnd why are some of the donuts rainbow-colored?

  • I want to know what an atom looks like! Andwant that picture to actually have something  

  • to do with the nitty gritty reality of atoms  (since they are, indeed, real things). You know,  

  • like how a diagram of the solar system is both  a totally-not-to-scale caricature and yet also  

  • represents the very real idea that the planets  all orbit the sun in roughly the same plane,  

  • and that some are farther out and some  are closer in; and if it's animated we  

  • get to see that the closer planets complete  their orbits more often. It's a nice picture!

  • And that's what I want for atoms: a good picture. There are a few things I'd like that picture to  

  • get across, some of them because  they're important for the physics  

  • of atoms, and some of them because they're  questions my brain wants answers to. Like

  • Where is the electron? How fast is it orbiting

  • How much energy does it have? How big is the picture relative to other pictures?

  • Of course, the wave-particle nature of quantum  mechanics means some of these ideas (like the  

  • electron's position) don't translate exactly from  our everyday intuition to the atomic scale...  

  • BUT, there is a way of thinking about  wave-particle duality where you picture  

  • the wavefunction as a bunch of water, and the  particle as a speck of dust in that water;  

  • the particle is mostly guided by where the water  goes (and the water is guided by the equations  

  • that determine how water behaves depending  on its circumstances). And, if you apply the  

  • mathematics of that idea to atomic orbitalsand then render it in 3D, here's what you get.

  • Isn't it beautiful? Here's another

  • And another.

  • In fact, I made a bunch of these. And  they're all mesmerizing, and beautiful,  

  • and isn't the ground state of the hydrogen atom  just so cute?? And aren't the excited states so  

  • majestic? There's so much structure and detail in  them, I love it. You can see the patterns in the  

  • orbitals, you can get a sense that they actually  ARE orbitals (I mean, something is orbiting!).

  • Ok, so I do have to be clear: the dots don't  each represent a separate electron - the whole  

  • collection represents the wavefunction of a single  electron, and the individual dots represent all  

  • the places that electron could be (a higher  density of dots means a higher probability of  

  • the electron being there). Electrons with more  energy are more likely to be far away from the  

  • nucleus, so higher energy orbitals are biggerThe motion of the dots is showing theflowof  

  • the wavefunction, and DOES correspond to an extent  with its actual angular momentum, though they're  

  • NOT electron trajectories. Unless you think  Bohmian trajectories are real (in which case,  

  • they really are electron trajectories!). I'll let  the philosophers of physics fight that one out.

  • But the point is these visuals are created by  representing actual electron wavefunctions in a  

  • visual language that our brains can understandthat of objects and light and shadows and motion  

  • in 3D space. There's actually stuff orbiting!!  And they're pretty! I hope you like them too.

  • Oh, one final thing - I 100% get that these  are not easy to draw. So if you want a cartoon  

  • representation of an atom that's simple  but more closely based in atomic physics,  

  • here's my proposal: it's based on the three  “P” orbitals (the ones from the “P” block of  

  • the periodic table): one of them has the electron  orbiting one way, one in the opposite way, and in  

  • the third one the electron is orbiting the same  amount but around some perpendicular direction,  

  • and we can't know which, which is why the points  aren't moving in the middle orbital, and why I've  

  • drawn a dotted line and question mark for the  sideways circle. And if you want you can add  

  • an electron to each orbital - or two electronsif one is oriented spin up and one spin down.  

  • THIS is a MinutePhysics-approved  cartoon representation of an atom.

  • Thanks to Google for sponsoring this portion  of my video. When Google reached out to  

  • sponsor MinutePhysics, I immediately  said yes, because I use Google search  

  • literally every day for everything from 3D  software tutorials, to physics equations,  

  • the weather, recipes, and of course coronavirus  vaccine information. And Google has been focusing  

  • a lot on supporting individuals and small  businesses over the last year - Google can  

  • even help *you* or your family and friends  discover opportunities and find jobs where  

  • you live! Just search "jobs for physics  majors" or "jobs for veterans in Montana"  

  • or "jobs for" whatever it is you do, and Google  will help you find opportunities tailored to you!  

  • Thanks again to Google for sponsoring  this part of my video, for making it  

  • easy to convert centimeters to inches, and for  helping us all find the information we need.

  • Ok, the sponsored segment is  over and you're still here!  

  • You probably want to know about the  rainbow donuts. The color there represents  

  • the "phase" of the wavefunction, which informs  how different wavefunctions interfere with  

  • each other, and it's essentially being  represented by motion in my 3D visuals.

Thanks to Google for sponsoring a portion of  this video, for supporting small businesses,  

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 electron orbitals orbiting atom atomic picture

A Better Way To Picture Atoms

  • 3 0
    Summer posted on 2021/05/19
Video vocabulary