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Sub Atomic Particle Sizes (Orders of Magnitude related)

  1. Jun 21, 2012 #1
    Hello my name is Brendon.

    I'm a graphic designer currently studying an MA. My major project is based around Eames' Power of 10 film and more recently the Huang twins Scale of the Universe website.

    I'm trying to reproduce these ideas in print, using folding to represent the orders of magnitude. However not being a man of science (i love physics but don't have 'technical' brain), i'm finding it difficult to make sense of a lot of the information i find.

    My main resource has been the Orders of Magnitude Wikipedia page, as this is the only place i have found the sufficiently aggregates the information. However, i'm aware than wikipedia is not a valid source for academic citation - and i'm trying to do some research myself to verify the information. However when following links i often end up running in circles.

    My question is whether anyone would be able to help me verify and confirm information regarding the sizes/lengths (whether they're confirmed or theoretical) concerning the information in these images:

    [PLAIN]http://postimage.org/image/brzv4e225/full/ [Broken][/PLAIN]

    image host[/PLAIN]

    Any help would be very greatly appreciated.


    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Jun 21, 2012 #2


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    :confused:10 chars
  4. Jun 22, 2012 #3
    The project is essentially a study to see if the materiality of printed matter combined with haptic senses can enhance the learning experience. It a series of very large fold out posters, in which each plane represents an order of magnitude.

    Does this clarify it any further for you?
  5. Jun 22, 2012 #4


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    Sounds very cool. I'm not much help getting your numbers though.
  6. Jun 22, 2012 #5
    electrons are point particles, and thus have zero volume (no size).
    protons and neutrons are made up of quarks. quarks are point particles and have zero volume.
  7. Jun 22, 2012 #6
    thank you jnorman,

    so is the information relating to powers of 10 in the above pictures just straight up wrong - or is there a suggestion that the sizes are in some way hypothetical?

    can someone explain to me how something can have mass yet no "size"?

    forgive me for my ignorance i really have zero knowledge with regards to the technicalities involved.

    thank you

  8. Jun 22, 2012 #7
  9. Jun 23, 2012 #8


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    Regarding elementary particles (quarks, leptons (e.g. electrons, neutrinos)) they are (today) considered pointsize (zero size), whether they have substructure or not is unknown (see e.g http://math.ucr.edu/home/baez/physics/General/open_questions.html#particle). AFAIK, the physical sizes that sometimes is referred to are upper limits, i.e. the maximum size the object could have (if it has a size :)). I think estimates like these are somewhat related to how Charge radius is measured, but I'm not an expert on this, so if anyone has better info, please correct me.

    If I could answer that, it would be worth a Nobel Prize :smile:. Seriously, the search for the Higgs boson is about how elementary particles gain mass (see Higgs mechanism).
  10. Jun 23, 2012 #9


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    Just another note regarding the Huang twins Scale of the Universe website (I tried their application some months ago):

    1. At 10-16 m you see a note saying "Lengths shorter than this are not confirmed". So their sizes regarding quarks and neutrinos are quite hypothetical (I don't know where they got their estimates from). Personally, if I did a presentation like this I would stop at this point and simply list the quarks and neutrinos and write "size unknown" and/or upper limits.

    2. They illustrate atoms with electrons classically orbiting the nucleus (protons/neutrons), which is quite common (and simplified), but I should point out that that view is obsolete. That's the old Bohr model, superseded by quantum mechanics, see Atomic orbital. I would personally visualize the atom with a nucleus surrounded by an electron "cloud" (the electrons have no definite positions, just probabilities that they are/can be located at particular positions).

    3. Regarding the size of the Universe, they give a strange entry which easily can be misunderstood. The size of the (entire) Universe is unknown. The radius of the observable Universe is estimated to around 47 billion light-years. They probably used a common misconception (see "78 billion light-years" (a lower bound) and "156 billion light-years" here: http://en.wikipedia.org/wiki/Observable_universe#Misconceptions).
    Last edited: Jun 23, 2012
  11. Jun 23, 2012 #10
    DennisN thank you very much!

    This is exactly the kind of explanation I was looking for!

    Part of my research is going to be a comment about the difficulty of researching this information (as a layman) and how things such as the Scale Of The Universe application can promote misconceptions by not citing any sources for their estimations.

    Regarding "upper limits" - is there a source of information that you know of, which states these in layman's terms? i.e. as powers of -10m? I don't really need to get too technical with my research, as a graphic designer i just need to make sure that the information i do get comes from a reliable, citable source.

    If not i'll just have to figure out a way of visualising this area of the project that is slightly different than it is now. At the moment it all fits rather neatly into a series of 10 posters - with a little juggling at the very smallest orders of magnitude (because its sooo strange down there).

    Anyways thank you for your replies!

  12. Jun 23, 2012 #11
    Is anyone able to explain the following reference on wiki for me please:

    Carl R. Nave. "Cowan and Reines Neutrino Experiment".

    Retrieved 2008-12-04.

    (6.3 × 10e−44 cm2, which gives an effective radius of about 2 × 10e−23 m)

    how do they actually work out the (hypothetical) effective radius?

    I can find sources which state the length 6.3 x 10e-44 cm2 but nothing which confirms the measurement of 2 × 10e−23 m or how they worked it out.

    many thanks

  13. Jun 23, 2012 #12


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    I don't know how they might do it for neutrinos, but for standard subatomic particles such as electrons and protons, they can do it by firing them at a sheet of gold and seeing how many particles get close enough to a gold atom to be deflected.

    What they are measuring here is not the size of the physical particle, but the size/ strength of the charged field that interacts with the gold atoms.
  14. Jun 23, 2012 #13

    is this what produces the wonderful scatter pictures is see so often?

    These kind of obvious explanations are exactly what i'm after! There is so much information to go through and so many concepts for me to try and learn in a relatively short space of time.

    I'm still puzzled by the actual maths though.

    Are these two numbers the same, but just expressed in a different way:

    6.3 × 10e−44 cm2


    2 × 10e−23 m

    or do you think that there is some formula that has been used to arrive at the second number?

    again sorry for being so needy here, my brain is quite literally frying...


  15. Jun 23, 2012 #14


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    No. One is an area (n2), the other is a length, so they can't be referring to the same thing.
    Even if they were the same unit, their scale is different by 17 orders of magnitude (that's a hundred million billion billion times).

    Furthermore, that first number is more than billion times smaller than the smallest possible length (er... area) the universe is hypothesized to allow - the Planck unit of length is on the order of 10-35m.

    To my only moderately-educated eye, that first number is nonsense.

    I suppose it behooves me to ask where you got them from.
    Last edited: Jun 23, 2012
  16. Jun 23, 2012 #15
    things are beginning to make sense!

    your help is very much appreciated

  17. Jun 24, 2012 #16


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    Hi Bren!
    I think those are really good and important points! Yes, it is difficult, but after all you are venturing into two big and naturally "fuzzy" frontiers of physics; particle physics and astrophysics/cosmology, where there are lots of unknowns. And the point about misconceptions/citing sources is very important indeed! In internet talks, I often refer to Wikipedia simply because it's fast and convenient, but it's of course not always reliable. Two good things about Wikipedia IMO are that you often can find links to primary sources, and that you can find interesting discussions and links on article talk pages. Regarding simplifications in general I'm usually positive, as long as the basic idea gets across without getting too distorted. But I really don't like the old Bohr model I mentioned above, it fooled me personally for many years until I got more acquainted with quantum mechanics.

    No, I have no numbers nor any source. The Particle Data Group link submitted above is a good one, but I didn't see any size estimates there.

    But I just remembered there was a thread on this forum which discussed this a while ago:

    "What exactly is an electron?" (page 2)
    (see the entries from A. Neumaier and Vanadium 50, and you'll understand that these things and their sizes are not very clear-cut :smile:)

    And here's another one which discusses it briefly:
    "Size of particles"

    Yes, it's strange down there! And very interesting!

    You're welcome! I wish you good luck with your project!

    I also second all Dave said above. I don't know how they do it with neutrinos. Or how it's done with quarks (if it's done?). I actually would very much want to know more about it myself :smile:. Bren, you could also post a question in the subforum "High Energy, Nuclear, Particle Physics", maybe? (https://www.physicsforums.com/forumdisplay.php?f=65)
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