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B Is it true that objects cannot touch each other?

  1. Oct 31, 2016 #1
    Some scientists say that objects do not actually touch eachother since the electrons repel eachother. And here is a video where a physics Professor (Philip Moriarty) explains the touching process between objects as the contact point where the attracting and repelling forces reach an equilibrium :

    What is your opinion about it?
  2. jcsd
  3. Oct 31, 2016 #2


    Staff: Mentor

    If there wasn't a thing like electromagnetic forces, we would likely fall into earth since most of matter is simply empty space.
  4. Oct 31, 2016 #3
    Actually there would be no earth to fall thru. Plasma perhaps?
  5. Oct 31, 2016 #4


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    Sure, you get into all kinds of questions about "what is a particle", "what is touching", "what is the volume of a particle", etc. Many of these questions can take on a philosophical element.

    Generally, fundamental particles - such as an electron - are considered as points without any internal structure. When considered in that manner, they have no volume. For all practical purposes, they could never interact by virtue of occupying the same space. However, particles manifest field effects. Those account for the impression of a particle having a size, and being able to interact with other particles.
  6. Oct 31, 2016 #5


    Staff: Mentor

    Yes. And at the end of those thoughts there won't be much left of our universe as we know it. IMO @DrChinese has said everything that can be said about it.
  7. Nov 1, 2016 #6
    Any opinion about the video I sent?
  8. Nov 1, 2016 #7


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    The video makes valid points. Both Moriarty's and Brady's (i.e., the man behind the camera) imputs are important here.
    I'd summarize it as follows:
    1. The everyday definition of contact, as vague as it is, can be thought of as: 'I can't put anything in-between two touching objects', or maybe something like 'solids are making continuous whole'
    2. This definition can't be applied to microscopic objects even in principle.
    3. There is a very precise definition of contact used in physics.
    4. Whenever you hear 'there's no contact, it's actually repulsion', it is meant to convey that the first definition can't be applied to microscopic scales and the actual interaction is similar to that of e.g. magnets repelling.
    5. But you should keep in mind that it's just a rough analogy, intended for the very narrow goal specified above, and the actual interactions are more complicated.

    I'd compare it to the case of teaching people about the Bohr's model of an atom: it's patently wrong, and if one's serious about physics, it needs to be unlearned at some point. However, if you don't know anything about how atoms are made, it's a nice, handy, easy to digest visualisation that conveys some valid points.
  9. Nov 1, 2016 #8
    What does interaction of electromagnetic forces mean? What is exactly meant by interaction here?
  10. Nov 1, 2016 #9
    What exactly is meant by interaction of electromagnetic forces? What happens during this process?
  11. Nov 1, 2016 #10


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    The OP has been banned for previous offenses under another username. This thread will be locked since they can no longer reply. Any members with questions regarding this topic are encouraged to make a new thread.

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