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Urgent Physics Question

  1. Mar 17, 2004 #1
    Question : A wall is placed in the middle of the room (not those thick walls but regular thin walls). And an object is continuously hitting it with a constant force. Physicists believe that if it keeps hitting the wall with a constant force, the atoms at that particular place on the wall will move apart and the object will go pass the wall (to the other side) and the wall will come back together (or rather the atoms will come back together). So my teacher asks if this is possible?

    It would be great if you can answer this really quick because I have to write a paper about it.
  2. jcsd
  3. Mar 18, 2004 #2


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    I know of no physicists who believe such a thing. Do you have any support for that statement?
  4. Mar 18, 2004 #3
    I read smt similar but not by hitting the wall...As far as I remember the book says that a car may cross through the garage door(Of course it is a very small possibility).It was a possibility let by quantum theory.Well, I was 14 or 15, now I study physics but I haven't taken quantum theory course.So I dont have any scientific support to that thing.
  5. Mar 18, 2004 #4
    I think I read the same thing in the book The Elegant Universe, by Brian Greence. From what I remember, there's a small possibility that a particle might temporarily acquire energy and pass through a solid wall, and return the energy afterwards. But the chances of that happening are small anyway, so imagine how small the chances are that a whole ball will go through a brick wall.

    But of course, if you hit the wall with the ball long enough, eventually it will go through. But you will also notice a ball-shaped hole in the wall. :wink:
  6. Mar 18, 2004 #5

    Chi Meson

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    As Brian Greene states, you will have to throw that ball against the wall close to an infinite number of times (or "for nearly an infinity"; both terms are nearly meaningless since you can never be close to infinity) before there will be a small change of this "tunelling" to occur.

    The book was already mentioned: "Elegant Universe." NOVA made a 3 part miniseries about it, but the book covers this topic a little better. No one is doing this experiment, however, since no one has several hundred trillion years to carry it out.
  7. Mar 18, 2004 #6


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    Uncomfortable as the thougth may be, the particles that make up the ball do not have any definite location, but only probable locations. The location of the entire ball is a result of averaging out the most probable locations of all the particles that make up the ball. Because these particles number ni the billions of billions, the sampling being averaged is very large, and the average is quite accurate.

    However, the possibility of any particle in that ball being ten or twelve centimeters away from where you see it is NOT zero, it's just very very small. So, if any particle in the ball could eb on the other side of the wall, then it si possible for all of the particles in the ball to be on the other side of the wall.

    As for the term "nearly infinity", perhaps the term "practically infinite" would be more proper. If you threw the ball against the wall once per second, and started doing so at the moment of the Big Bang right up till today, you still would not have done it enough times to have a fair chance of seeing the actual event of "ball tunneling". Any event that takes longer than the age of the universe is, in practice, infinite. Therefore, the event that could take place in theory cannot in practice due to the "practically infinite" amount of time required.
  8. Mar 18, 2004 #7


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    I truly and sincerely wish that this isn't a question about quantum tunneling, as everyone here is guessing. If it is, this is a very sad, horribly distorted, and at best, misleading discription of it. "... atoms.... move apart and the object will go pass..... the atoms will come back together..."? Someone in charge of the educational standards at where you are needs to be informed of such gross inaccuracy. And your teacher needs some serious physics lessons.

  9. Mar 18, 2004 #8
  10. Mar 19, 2004 #9


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    But he is right.
  11. Mar 19, 2004 #10
    THAT'S what makes it an ouch!
  12. Mar 19, 2004 #11
    wa sa this is sounds fantasy only if the ball it self is a wave or something ,

    i dont think it is possible, consider the light is focus on a non transpercy object no where in the world it would go through it. no matter how long u focus. wait i m not talking about laser. just normal light beam. =D
  13. Mar 19, 2004 #12
    {i m not professional} it might be true for some toppest scitenist ....
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