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How do we know if electrons are spherical?

  1. Jul 6, 2007 #1
    When we study physics or chemistry, we often see particles, atoms, neutrons, protons, electrons, etc being portrayed as little spheres.

    But in fact, how do we know if they are spherical?
  2. jcsd
  3. Jul 6, 2007 #2


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    Staff: Mentor

    Most aren't spherical, that's just a representation for simplicity.
  4. Jul 6, 2007 #3


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    Homework Helper

    Yeah but it's kind of misleading. A related question would be why the couldn't use cubes, diamonds, heart shapes instead universally. Note that this isn't a science question.
  5. Jul 6, 2007 #4
    I don't know, but maybe sphere is considered the simplest symmetric 3D shape, which helps in making calculations less complex.

    Mr V
  6. Jul 6, 2007 #5


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    Staff Emeritus
    Science Advisor

    In fact, at the level of electrons and other elementary particles, ibecause of quantum indeterminacy, it is wrong to use the concept of "shape" at all.
  7. Jul 6, 2007 #6
    Yeah you right. It was my mistake. There is no notion of a definite shape at the level of electrons. It is all too complicated at that level.

    Mr V
  8. Jul 6, 2007 #7
    In fact, we know with much certainty that electrons do not have shape at all. They exist only at a point. In fact, it could be quite possible that protons and neutrons only have a shape because they are made of three quarks that can't exist on top of one another. If we could only see a lone quark we may be able to see that the quarks exist only at a point as well. Then all shapes and volumes would be a manifestation of the repulsion between points.
  9. Jul 6, 2007 #8


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    Gold Member

    Being portrayed as spheres in diagrams does not indicate anything about their physical properties any more than being coloured blue with a black line around them.

    The sphere is the symbol that requires the least description - needing only a radius - and is therefore the least misrepresentative. If they drew atoms as little cubes, then the first question asked would be "What's with the 8 pointy bits?"
  10. Jul 6, 2007 #9


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    Remember that our "atom" really is a model. We can't really see what they physically look like. We use a model to describe it.

    If atoms weren't treatable as spheres, it would be because some part of their physicality sticks out more than some other part (say, taller than it is wide) - you would be able to "orient" an atom. Which you can't.

    While atoms may not actually be little hard balls, their interaction with the world really is as if it were a sphere.

    Subatomic particles OTOH, are points; they have no dimension. But they still interact with the world in a spherical manner (i.e. same in all orientations.)
    Last edited: Jul 6, 2007
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