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Pushing and making holes

  1. Apr 24, 2006 #1
    When you push your finger into the bread you see how it drowns and makes a hole after a short while. Also when you push your finger into the cake, you find your finger making a hole. The same is with the sheet of paper. But on the other hand when you try to make a hole in at least one of 100-sheet stack you find yourself not making a hole in any of them. There are many other objects that take less or more pushing to make a hole. But when you push your finger into the wooden door you don't find your self making a single change, but since there are so many materials and many of them are "hole-making" and many or not, I think that after all it may definitely be possible to make such hole in anything out there, it just may take some time. SO here's my question, why is it happening? and is there any formula that lets me find a time needed to make a hole in any object after its chemical structure?
  2. jcsd
  3. Apr 24, 2006 #2
    Not really sure what you mean here. You can make a hole in pretty much everything. If you want to make a hole in a piece of wood get a drill. If you want to make a whole in rubber you can get a piece of hot metal. If you just want to push your finger through a piece of wood then you're going to be waiting a long time. I'd imagine the wood would decay before you could put your finger through the material (depending how thick, type of wood, etc.). Other than that, there are quantum theories that state energy can be borrowed & theoretically you could push your finger through the wood. However, to push such a large object through a material is very unlikely & would take an eternity.
  4. Apr 24, 2006 #3
    I think this might be about bonding in the material right? That occurs on quite a few levels. It can be between the atoms the material is made out of or just how the fibres of something interlock with each other.

    The only reason you can't push your finger through something like a piece of metal is that your finger isn't putting enough force on the bonds between the metal crystals & atoms to break their bonds.

    If you were to use a diamond point and fit it to a huge hydraulic cylinder, you could easily push it through a piece of steel. Infact, the steel would look more like butter to the diamond than a solid.

    As for calculating the force needed, that's quite a complex question, purely because the force can arise at different levels within the material. If the material was a perfect crystal say, you could estimate it if you knew the bond strength of the atoms within the crystal. But in the real world things don't usually crystallise perfectly and you end up with lots of crystal domains in the same chunk of material (a polycrystalline), which will break more easily than they would if they were one continuous crystal (a monolith). Then that crystal might be processed on an even higher mechanical level, mineral wool insulation that's spun into a blanket for example.

    As heartless says, theoretically you finger could just slide through something if the energy were to randomly distribute itself in a particular way at your finger tip. But the chances of it happening are pretty much zero. By comparison, winning the lottery is almost a dead cert.

    Push harder and you'll be making holes in everything!
    Last edited: Apr 24, 2006
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