This week in my art studio I thought I would learn some theoretical physics and finally wrap my brain around what’s known as the uncertainty principle. Also? Hummingbirds.
The Heisenberg uncertainty principle states that there is a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known.
In layman’s terms: the more precisely one property is measured, the less precisely the other can be controlled, determined, or known. Thanks Wikipedia, you have a lot of information to share but I think we need a way to help us visualize this principle.
Lucky for us, I stumbled across what may be the best analogy I have heard that helps to explains this principle in Brian Greene’s book, The Hidden Reality. In the book he tells you to imagine you are taking a photograph. If you take a photo of a moving object with a slow shutter speed the image you get back of that object will be blurred. Therefor, the image is giving you some information about the movement through space or speed of the object but not its exact location.
If you instead turn up the shutter speed you can get a photo of the object in focus and seemingly frozen in place. That photo can give you information on the exact location of the object but no information as to how fast it was moving. Much in the same way you that you can’t determine the exact speed and location of a particle, you can’t capture both movement and exact location in a photo. Because of how you view an object you can only clearly capture one bit of information or the other.
I thought it would be fun to go outside and take some photos to try and recreate this analogy. I decided to snap some photos of the fastest things I could find in my yard and found some hummingbirds more than ready to demonstrate their wing speed and the uncertainty principle for us!
Of course please remember that when physicists are talking about the uncertainty principle they are actually talking about tiny particles and the quantum realm. So please do keep in mind that these hummingbirds photos are just a way to try and help us visualize what happens on super-small scales and is obviously not an accurate representation of particle physics.
Hummingbirds in motion.
Hummingbirds in space.
This was a fun way to visualize the fundamental problems in capturing both the speed and location of a particle. If only the rest of theoretical physics was as easy to visualize!
I also made some art with the mathematical representation of uncertainty principle!
I love Brian Greene, but haven’t gotten the chance to read The Hidden Reality. Awesome. This article gave me the ‘aha!’ moment for the Heisenberg Principle I could have used in high school.
The book is really interesting if you like theoretical physics. I actually got the audio version and Brian Greene himself narrates it so it is a double win!
Your equations are always so pretty, Amy!
I had the exact same reaction to Greene’s analogy when I read it — it’s so clear and easy to understand that I’m almost a little skeptical that it’s not a misleading one (why haven’t all texts been explaining it that way!)
Also, I remain bitterly jealous of you west coast folk and your hummingbirds. I love our RTHUs, but a little variety would be nice. 🙂
Thanks quarksparrow!
As for being misleading I too have to assume that anything in the human visual realm being compared to the quantum or particle realm has to be at least in some sense misleading.
I would say that it’s only misleading if you take it too literally. Personally, I think the mental image of a photo blur is a good one to work from. There are so FEW good mental images offered up by quantum mechanics; you have to take what you can get.
Where quantum particles differ from hummingbird wings is that not only must electrons be observed as blurry, but that the electron really IS blurry. Blurry in some fundamental way that has less to do with the limitations of our cameras than with the limitations of the very building blocks (i.e. “quanta”) of reality.
PS: Oh, and ditto the appreciation of your care for detail in rendering equations.
My favorite/terrible joke:
Heisenberg was driving a car. From behind he hears a siren and sees a police officer is pulling him over.
The cop comes up to his window, so naturally, Heisenberg rolls it down.
The cop asks “Sir, do you know how fast you were going?”
He replies “Sure don’t, but I know where I am.” —
Ha, maybe?!
It made me giggle. 🙂
Great photos! It’s a nice analogy you used, too.
That is so cool! And wow, hummingbirds are gorgeous! We get a few of them here, but unless you’re actively feeding them you never see them (and certainly not at this time of year, it’s still winter)
I love this and I love BG! What a wonderful (and beutifully inspiring) way to think about position&movement!
But since people are asking… I think one way that the anallogy can be a tad bit misleading is that it suggests that the problem is with our technology – the camera is not the best tool to capture all the hummingbird info at once. This could suggest that if we invent a better camera we can know it all. But – (if I remember my QM classes properly!) the properties of not-knowing actually are inherrent to the particle, not any problem with the instrument of detection.
Oops! I now see that breadbox already said this – and more succinctly than I did!
Thanks Raven! I also think that part of the problem in thinking in terms of photography is that by the time the information about the particle reaches your method of viewing it, the particle has moved. Or it has moved because you have viewed it. This is not a problem with photographing large objects.
My twitter and Mad Art Lab friend, Chainbear said it was a lot like pool balls. To see an electron you have to bounce a photon off it. Much like with pool or snooker balls these two things bounce off of eacother so by the time you "see it" the electron is actually somewhere else. So it's not a problem with equipment it is a fundamental problem with viewing.