The Uncertainty Principle


Today’s Music: They Might Be Giants – Particle Man

The Heisenberg Uncertainty Principle refers to measuring the position and speed of tiny particles in the quantum physics world. It states that the more precisely one property is measured, the less precisely the other can be controlled, determined, or known.
For those of you expecting a waggish post relating to why I always lose socks in the laundry, or why I can never find my keys, sorry to disappoint. While those are both interesting topics deserving of further attention, I’m actually going to stick with physics here.

I’m not a scientist. My math skills are adequate but unimpressive. But science, and quantum physics in particular fascinate me. The search for an explanation of the universe, from it’s largest phenomena to it’s smallest appeals to the tinkerer in me.
And while I knew what the Uncertainty Principle said, I never quite grasped the meaning.
Finally, someone explained it to me in a way I could understand.

It's not really there...

Right now, you’re able to see this because photons (light particles) are bouncing off whatever screen you’re looking at and reflecting onto your eyes.

Now think about the size of a photon vs. the size of your screen. there’s no comparison. Your screen is bombarded by photons, but because of the size difference, the constant barrage makes no difference.

Now shrink it down. Say to the size of an electron.

Objects on your monitor are MUCH smaller than they appear.

The photon and the electron are not that dramatically different in size. In fact, they are close enough, that the momentum of the photon that bounces off the electron is enough to move the electron, like you being bumped in a crowd during, say, a rush hour train commute.

So, the Uncertainty Principle (simplified) says you can either know the Speed of the electron OR it’s Position.
If I figure out the speed of the electron, I’ve done this by bombarding it with photons. How fast the electron passes through the photons tells me how fast it’s moving.
But since each photon that hits the electron changes it’s position a bit, I don’t know exactly where it is. To note it’s speed more accurately, I have to hit it with more photons, bouncing it around even more.

Going the other way, say I want to know where the electron is. So I tap it with just one photon. That will give the least bounce against the electron. So now I know where it is.
But because there is only the one (or other very small amount) of photons, I can’t track the speed of the photon.
I can only know one or the other.
Still with me? No shame if you’re not. Honestly, I first heard of the Uncertainty Principle in high school, and it’s taken me to the start of middle-age before I understood what it meant.

The explanation that cleared it up for me came from Dr. Brian Greene’s eminently readable The Elegant Universe. Seriously, there is very little math in the book, and some of the analogies are hilarious.

So, back to the Principle.
Since only one condition (speed or position) can be known at a time, only the probability of the other can be measured. If the speed is known, then I can only say that the electron is between a probably range here and there.
If I know where the electron is, I can only say it’s going between a probable range of this fast and that fast.

Albert Einstein (the guy with the hair) famously said “God does not play dice with the universe”. He never agreed with the uncertainty principle because it relied on probability instead of a solid “it’s going this fast, and it’s here”.

Do I look uncertain to you?!?

Now, all these years later, I finally have some idea of what the hell he’s talking about.
How cool is that?

****EDIT – If anyone sees anything wrong in the above, please correct me in the comments and I’ll update the post!!!Β  Thanks.

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53 responses to “The Uncertainty Principle

  1. THWAP! That was the sound of my head slamming into a brick wall.

    On a note related to only one word, but not in the same context at all, my husband got the Motorola Photon 4G this summer. It is amazing. He sits in the passenger seat and watches sports while we go places, it’s a WiFi hot spot that’s faster than a lot of other WiFi, it even has a kick stand.

    Like

    • Isn’t science fun?

      I thought Sprint was clever – my Moment ended up lasting to 3 months before I’m eligible for an upgrade. Fortunately, they agree the break was their fault so they replaced it. With the same outdated phone.

      Please tell me he’s getting the kick stand chromed!

      Like

      • That’s a good idea. He should have that thing chromed. I’ll suggest it. I have a Moment too! I got mine almost 2 years ago, nearing upgrade time. This is a funny story actually. I bought it and 22 hours later dropped it face down on the only piece of tile that sticks up in my office foyer. Shattered the screen. We ordered a new screen from China and Nick soldered it on for me. It’s been working fine ever since. I have gone through 4 phone cases though. I drop this thing at least 3 times a week. I hate it in comparison to the Photon, but am not willing to spend $400 on a phone just to get it a couple of months early. I’ll get something with Ice Cream Sandwich when the time comes. Woo hoo!

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        • I bought a screen protector from Zagg.com and with it, I have bounced my phone off pretty much every surface there is with no screen damage.
          It’s a little difficult to apply, but totally worth it.

          Just keep your fingers wet with their spray so you don’t get fingerprints on it!!!

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  2. You lost me at the . . . Not really. I sort of actually understand this. My question is why? Why do we care about the speed or position of an electron? I guess what I’m saying is what are the ramifications?

    My husband loves this stuff. I think I’ll get him The Elegant Universe for Xmas.

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    • Well, one of the reasons it is pursued is to develop a deeper understanding of how the universe works.
      One of the things Heisenberg did with the Uncertainty Principle was resolve a conflict in equations trying to state position and speed. His principle shows that probable (as opposed to “definite”) is inherent in quantum mechanics and not a flaw. That was Einstein’s objection..

      The ramification was that it allowed thinking to continue in quantum physics with some fundamental questions resolved. This has led mostly directly (from what I understand) to the current search for the Higgs Boson (also referred to as “the God Particle”).
      From a practical point of view, will this give us a better toothbrush? Probably not.
      But the internet was also developed from a theoretical “what-if” question, so who can tell…

      Sorry to run so long, Linda, but your question made me think – a lot. And I had to do a bit of research to get my facts straight. Which I still might not have…

      If anyone catches any flaws in my post/comments, feel free to correct!

      Like

  3. pursuitofhappieness

    Very cool!

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  4. Hi,
    Wow way too early in the morning for me to get my head around that one. πŸ˜€ (It’s just after 5am here, and I’m enjoying my first cup of coffee)
    However “The Elegant Universe” sounds rather interesting and I will have to check that out. πŸ™‚

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    • I feel your pain, magsx2 – I should have started the post with a warning.
      If you’re into this kind of thing, I’m finding The Elegant Universe to be an excellent book.

      Like

  5. Great explanation for the layman/woman. BTW did you ever see the Animaniac’s cartoon with TMBG’s Particle Man as the theme and cartoon?
    Hilarious. One of the great things about having a kid.

    http://www.evtv1.com/player.aspx?itemnum=1758

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  6. Here’s a fun and interesting interpretation of the TMBG song:
    http://linkstew.org/1999/04/920/

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    • I loved Animaniacs/Tiny Toons. No idea how I missed this video – thanks for the link
      And the in the second link – wow – you’re man put a lot of thought into that!
      Thanks for the links – good stuff, and hope the explanation was comprehensible. I’m literally overjoyed I actually understand it after all this time…

      Like

    • Very cool. ❀

      Like

  7. I find all this stuff fascinating. It makes sense when I’m listening to the explanation or reading it, but a day or so later, I can’t explain the concept. The Elegant Universe sounds like an excellent read.

    Like

    • I wish I could retain more than a tiny fraction of the science I read.
      I’m lucky I’ve retained a working definition of fractions!
      You’re right though, it is fascinating stuff.
      Thanks for coming by!

      Like

  8. The Elegant Universe is a MUST read πŸ™‚

    Like

  9. Well, I must say it is taking me a minute or rather – I read this early this morning too – before my coffee and I have been thinking about it until I felt alert enough to try again. AND ok, I am grasping it, I am in one of those cool places that makes you fee llke you are approaching something hugely profound. It is is the middle of my brain and I don’t know what I am thinking specifically – if I did I wouldn’t be able to tell you from where the thought originated.
    Excellent incorporation of waggish – Bravo! You Rock and I am going to have too think of something before Saturday for a prize πŸ™‚
    Great post – πŸ™‚ Peace

    Like

    • These guys thought all day and changed the world.
      Profound is a perfect word, Lizziecracked.

      And reading your posts is prize enough!
      (though I’d not say no if a donut was saved…)

      Like

  10. I was with you until the song ended.

    “Is he a dot, or is he a speck?
    When he’s underwater does he get wet?
    Or does the water get him instead?
    Nobody knows, Particle man”

    You’re obviously way smarter than me. I would love to hear about those renegade socks though. πŸ™‚

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  11. What Edward said. I was thinking 2 things. I will have difficulty finding some thing wrong so I’ll take your word on this and second, a different uncertainty principle. “Doesn’t “expecting the unexpected” make the unexpected expected?”

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  12. LOL! Very cool indeed. I’m with you – science really is fascinating. Love that song by They Might Be Giants – hilarious!

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    • Thanks. I love this stuff!
      Surprisingly, TMBG they have a bunch of educational songs too – Why Does The Sun Shine, James K. Polk, Supertaster…
      The list goes on

      Like

  13. That’s a good explanation, Guapo.

    There’s another example of the principle in experiments with light, which acts like either a wave or a particle, depending on how we observe it. Set up an experiment to check its particle-like properties, and it behaves like a particle. Devise an experiment to look at its wave properties, and it acts like a wave. But when we’re not observing it, light is both a particle and a wave, or neither one. Our observation of light–or anything in the universe–affects its behavior. Open the box to check on Shrodinger’s cat, and it assumes either an alive or a dead state, but until you check, it’s both alive and dead at once (or it’s neither alive nor dead).

    In related news, scientists at CERN’s Large Hadron Collider think they’re very close to finding the Higgs boson, sometimes called the “god particle.” Finding it would confirm some big, fundamental theories about the creation of the universe, the nature of matter, and most of what physicists have been studying for the past hundred years. Oh, wait though… they say within the next several months they’ll either have the Higgs boson pinned down or prove it doesn’t exist. Either one will be HUGE, but if it turns out to be the latter, our understanding of physics will be turned on its ear. This geek (thumbs pointing at myself) is looking forward to news from CERN.

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    • I’ve been following the Hadron collider experiments. Right now, they are trying to corroborate results they’ve had that suggest circumstantial evidence the particle may exist, but it isn’t sure enough yet.
      Yeah, all us geeks are waiting for the results!

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  14. I’m not ashamed to admit that I had to read every. single. word. carefully. to. figure. out. what. the. heck. you. were. talking. about. But I got there. Just took a lot of concentration. πŸ™‚
    Interesting. And very insightful for me. I have a block with math. And science. Good thing I’m in marketing and not anything serious.

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    • No shame at all, theflameinside. I’ve reading and rereading about this for 20+ years and I only now have some inkling of it!

      And I bet you take your marketing very seriously.

      Like

  15. You make science fun, good sir!

    Like

  16. alfred beilin

    afternoon everyone hope yous had a nice xmas and heres to the new year
    alf beilin

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  17. I know exactly where I am. However, I have no idea how fast I’m getting there.

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  18. Are they going to let you know about the god particle directly? I’ve been having trouble getting people up at the collider to respond to my text messages.

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  19. I love physics as well and I am also not great in math. However my understanding of Heisenberg’s Uncertainty Principle it relates to the measurements of tiny particles and how we (humans) affect that measurement. He concluded that to understand where something is and measure it’s distance or even it’s speed and velocity is complicated by the fact that we affect it with even the light we use.

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    • That’s about it, V.
      The problem is that the light particles (photons) bouncing off a small particle affect the position of the particle.
      To measure it’s position accurately, very few photons are bounced, so position is less affected.
      To measure speed, more photons need to be bounced, which will affect position. Thus the exclusive nature of the 2 measurements.

      Unless I just confused us both…

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  20. Obviously a Pre-AFA post! πŸ˜‰ … Thanks for the link back to here. Easy to understand, well, relatively speaking. πŸ™‚ Very good.

    I brief mentioned Heisenberg’s Uncertainty principle relative to my fascination with the interchange between science and religion. You may enjoy my description of in in the third paragraph. But also trying to set up the video.You may recall this post. http://afrankangle.wordpress.com/2012/02/27/on-a-quantum-thought/

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  21. I get it! I get it! …and I was an art major! Very cool to understand and yet how did they figure that out? It must all be theoretical.

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  22. I hate not to get what Susie thinks she has got… I would have rather read about losing socks in the laundry. I have to agree with Albert.

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  23. Fascinating post, I look forward to reading more. I found you via Susie’s blog. I regret that I overlooked science when I was younger and in school, at least I have time to catch up now.

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  24. Well, crap. I’m blonde. *cries*

    I would like to know if that means you understand the movie Looper.

    πŸ™‚

    Like

Ahem *best Ricky Ricardo voice* Babble-OOOoooo!!!

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