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We never really touch anything?

  1. Jul 23, 2009 #1
    i was watching this show on the science channel called the known universe it stated that we never really touch anything because our skin is made up of atoms which have electrons and since the things we touch have the same we never actually come in contact with anything? if that is true how do we "feel" anything?
     
    Last edited by a moderator: Aug 11, 2013
  2. jcsd
  3. Jul 23, 2009 #2
    How does the sensation of "feeling" arise? Because there is a force acting on the nervous system. What causes this force? The Coulomb repulsion caused by the electrons, mostly.
     
  4. Jul 23, 2009 #3

    DrChinese

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    As an extension of xepma's post: what we call "matter" is quite nearly a perfect vacuum. The entire Milky Way once fit into a space much smaller than a human cell. Most interactions are due to the fields generated by the gravitational and the electromagnetic forces associated with atoms. Rarely do the atoms in your body actually come into direct contact with other atoms.
     
  5. Jul 23, 2009 #4

    HallsofIvy

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    Of course, whether we really "touch" something depends on what you mean by "touch"! I would consider the effect described by xepma and Dr. Chinese to be "touching".
     
  6. Jul 23, 2009 #5
    Touch, as noted, is rather subjective. on the other hand, even solid metals are 99.9999 percent ( I arbitrarily stopped typing 9's) "empty" space....feeling arises via information transfer.....evolutionary based sensory perception
     
  7. Jul 23, 2009 #6
    Even though things never "touch" as my finger, for example, gets closer to hitting a key the electrostatic repulsion as I get closer causes the surface of my finger to deform. Our brains/bodies have evolved to attach a sensation with a deformation of the skin. Think about a windy day, when the day is calm we don't feel air impacting on us but we know that it is and then a strong gust comes along and suddely feel like we're being pushed by a strong force. We were always being pushed around by air, our body's nerve just didn't really have the sensitivity to detect it before. Sensation is in the head.

    P.S. in the future you should probably post something like this in the General Physics forum
     
  8. Jul 23, 2009 #7
    Great post Dr. Chinese. Interesting topic OP brought up, I think touching would also be somehow related to the physiology of our nervous system.

    It's an electrical sensor after all, so there's no mechanical touching in the conventional sense.
     
  9. Jul 24, 2009 #8

    Yes, literally speaking we never touch anything. Electrons in the outer shells of atoms repel each other at 10^-8 metres.(yes, you aren't really sitting on a chair, but hovering/flying slightly above it at 10^-8m.)




    Buried in the skin, there are nerve cells, which have extra electrons they can release when acted on by a force from outside. These electrons flow along the nerves, atom to atom, eventually reaching the brain, where other cells interpret this electrical signal as 'pain'. At no time do any atoms or electrons actually touch each other; the only 'contact' is the electromagnetic force ( positive and negative) between particles.
     
  10. Jul 24, 2009 #9

    Sure, but that would be a totally new way of defining 'touch', as far as our perception of solid structures goes. Our perception doesn't reveal that when are having sex, we are actually merely exchanging photons with no physical touch between the atoms of...(don't tell your wife i told you this:smile:)
     
  11. Jul 24, 2009 #10

    negitron

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    [Morbo]NERVES DO NOT WORK THAT WAY! GOODNIGHT![/Morbo]


    Well, he's right, they don't. It's much, much more complex than that; suffice to say it's a combination of electrical and chemical signals that propagates along the nerve in stepwise fashion. Between nerves, across gaps called synapses, chemicals called neurotransmitters carry the message from one nerve cell to another. Most of the electrical signals aren't carried by electrons, anyway, but by ions, principally calcium and potassium.
     
  12. Jul 24, 2009 #11
    Is it only electron repulsion, or there is proton repulsion too? If you push someone, and if he falls down, the whole atoms moved.

    Why a touch doesn't cause an momentarily electric current?
     
  13. Jul 24, 2009 #12
    This sounds like Zeno's paradox all over. :)

    Touch is not just in the mind, in my opinion. I think when any two objects come into any type of meaningful contact, they are touching. I also would consider electric field repulsions to be touching, since they need a medium to be transmitted through. We create our own electric fields, which interact in "close" proximity with objects around us, i.e. we touch.
     
  14. Jul 24, 2009 #13
    boninthesand

    Here is a thread I started earlier that you might be interested in reading.

    https://www.physicsforums.com/showthread.php?t=301495

    I'm no scientist, but from what I've read in books recently, and from very smart people on this forum, I believe Dr. Chinese said it best above. All you are "feeling" are the electromagnetic forces of electrons in the hammer repelling the electrons in the rock. And the electromagnetic force is extremely strong.

    Daisey
     
  15. Jul 24, 2009 #14
    Yeah, this subject reminds me of two magnets in a repulsive arrangement.
    Of course, the issue here does not involve pure magnetism. Still, it reminds me of that.
     
  16. Jul 24, 2009 #15
    then if we are only feeling the electromagnetic pulses, than how do we manage to pick something up?/
     
  17. Jul 24, 2009 #16
    We can pick stuff up because of the friction between an object and our hands.
     
  18. Jul 25, 2009 #17
    As has been pointed out, the source of friction is coulombic forces (i.e. electromagnetic interaction) and, just as we are discussing here, when a block or something slides across something else, like with out hands, there's not actually anything touching. Keep in mind that the seperation between surfaces are on the atomic order so the distance would be about 1/100,000's the width of a human hair. So it's not like you can squint your eyes and see the seperation. You are familiar with a situation where the atomic nuclei of two atoms actually do touch... a nuclear bomb.

    P.S. Completely incorrect use of electromagnetic pulse btw (an EMP is a type of weapon/ phenomena following a nuclear explosion in atmosphere).
     
  19. Jul 25, 2009 #18
    Touch, or fuse?
     
  20. Jul 25, 2009 #19
    Uhh... potentially neither, fiss? Is that a word? Depending on the energy level involved and the nucleus under consideration this is either a fission event (like the original bomb where the atom "splits"), a fusion event (where the nuclei fuse), or simply isotope creation (where a neutron simply "joins" the nuclei).
     
  21. Jul 25, 2009 #20
    Interesting. Actually I was really wondering when two nuclei actually do "touch", does that always lead to a nuclear explosion. I'm guessing your going to answer by saying that two nuclei would only touch in situations where tremendous forces were added to make them touch, and that would inevitably lead to a nuclear explosion. And I guess it would follow that nuclei would never naturally (in nature) touch (unless the nuclei lived inside a star). Correct?
     
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