How come we can't walk through walls?

[masudr]

So, your question is, "How come we can't put one solid through another?"

 

[BB&A]

In response to masudr, that is the direct question I had in mind. But the water/air analogy mentioned above is a very good one..a solid can go through liquids and gases and remain intact. So, why is it -- at the atomic or even quantum level, is it not possible for a "solid" to go through a "solid" with each remaining intact after the passage.

 

[Wellsi]

what would happen if the solid entered another solid, yet was unable to continue any further and was hence stuck in the other solid? would ne thing special happen there?

 

[turbo]

what would happen if the solid entered another solid, yet was unable to continue any further and was hence stuck in the other solid? would ne thing special happen there?

Lets imagine that you have a block of iron and a block of copper on the desk in front of you. If you think that the nucleus and electrons of each atom are infinitesimal points, then you might imagine that each atom is mostly empty space and that you could slide one block through the other. This is not the case, though. The electrons are not little points, but are smeared over all the places where they are permitted to be, and they are already as tightly packed as permitted by the Pauli exclusion principle. Being fermions, they resist being packed any closer than they currently are (with same-spin neighbors). Because of the Pauli exclusion principle, it is impossible to superimpose the two cubes in one space at the same time. If you will Google "degenerate matter" you will find out more about how the behavior of fermions effects the properties of matter.

 

[BB&A]

Iron Block vs. Copper block -- why neither can go thru the other

Very well. Now, let's shift to the next scenario..I want to cut each block in half. I use a saw to do that. How is it that I can cut thru the interlinked bonds of the copper block's atoms? Perhaps put another way, how does brute force shear one copper atom's connect to the next causing them to separate?

The response to this is going to lead to my final question which is what force can be harnessed to allow the separated copper block atoms to remember their location with each other and rejoin once the "brute force" -- the saw -- leaves? Answering this will lead perhaps to the answer to the reason for my very first question (why can't we walk thru walls): Can a force be harnessed to allow the wall to part to allow our passage...This principle was shown by the "bad guy" in the sci fi movie, Terminator II.

 

[turbo]

It's only a movie special-effect. The robot had the (entirely fictional) ability to phase-change and to rearrange itself in any configuration to duplicate objects or people. Quite a handy plot-device, but it is nothing that we can make any material do. Look at an ice cube in a tray. We can leave it on the counter until it melts, then put it back in the freezer until it re-freezes. Is it the same ice cube with the same molecules all in the same relative positions? Not even close.

 

[antonantal]

Hey what if you go to school and walk through the wall of your classroom with a bulldozer Show those people what quantum physics is all about.

 

[BB&A]

Good line about the bulldozer...except the repair cost will exceed my tuition! Also, doesn't fiction inspire discovery as in - ahem - science fiction?

To the core questionm, is there a force that keeps the atoms of a block of copper with each other and ONLY with each other rather than drifting off somewhere else in a 72F room?

My wonderment is whether there is a force can be tapped to allow the mass of atoms to be moved to create a passageway without brute force or heat or chemistry...something at the quantum level that can be used as a "lever" part the atoms into creating a partition of the copper block.

 

[reilly]

Physical reality says solids do not pass through each other. So quantum theory has to yield that fact. It does.

In the classical kinetic theory of gasses there is a probability that all the air in a room will simulataneously arrive at a single spot in the room. So, there probably is some chance that solids can pass through each other. You can be sure that 1. It's unlikely that the probability can be computed except in a very approximate way, and 2. that probability is undoubtedly so small that it's negliable in practice, just as the "air" case above -- how many places store compressed air to safeguard aginst a temporary vacuum?

I do recall that, given enough time, a block of steel resting on a block of copper will merge into each other, due to thermal activity. In fact, I suspect that the Second Law of Thermo says that that merging must happen.
Regards,
Reilly Atkinson

 

[BB&A]

Reilly (and everyone else who participated in this thread, thank you for clearing up a lot of things).

 

[scarecrow]

Think of it like this. When your ceiling fan is off, you can easily put your hand through it and touch the ceiling. Now when it's on full blast, the blades start looking almost like 1 object, and if you put your hand in there, it's going to stop you.

Now think about atoms and electrons and such orbiting at light speeds. It may give the appereance of being 100% solid, but I doubt that's even possible. Anyways, I hardly know what I'm talking about, just referring to an example my chemistry teacher gave me way back in high school, maybe it'll help.

I love that analogy.

 

[Wellsi]

yes, that analogy was brillian thank you nexus!
we finally are doing Pauli Exclusion Principle in our chemistry classes now, thanks for the heads-up before hand guys haha i have abit of a head start now :)

 

[Wellsi]

Not to revive an old argument... but i am putting together sources to use in my essay here and have got one about the PEP and Degenerate Matter to explain that, one on probabilities of atoms lining up so that one object CAN pass through another and one analagy as to why it is so hard for one thing to pass through another.

If ANYONE has ANY ideas about cross-cultural relations to this topic... eg what has an asian/ african country contributed to the research or what is the opinion of scientists in this area... or something that involves developing countries it would be MUCH appreciated guys :)

 

[Haelfix]

My point of view is that it *is* possible in principle, but so astronomically small and unlikely that it will never happen. By astronomically small, I mean something so ridiculous its for all intents and purposes zero by any sane individual.

Consider what would have to happen.. All the molecules of the solid lattice would have to have tiny quantum perturbations within them, so that their substructure arranges itself in more and more unlikely configurations, so as to say self screen their own coulomb potentials. Worse you'd need all these molecules to enter a more or less coherent state amongst themselves, and presumably one that is bosonic in character. In otherwords you'd need to calculate the probability from quantum jitters alone for an arbitrarily long phase transition from solid to gas, that somehow miraculously doesn't decohere within the time frame, and somehow has interaction terms that are made to be small with respect to the incoming particles of the magician about ot walk through the wall.

In the first page of this thread, someone posted a number from classical reasoning alone. It is infinitely worse in the quantum picture, where now things have non pointlike spatial extent.

 

[disregardthat]

I have heard that in quantum physics, there is no certainty that one thing will happen, and if it will happen sooner or later. I have heard on television about the quantum theory (which usually exaggerates things) that all the things that MAY occur, actually occur, only in different universes. Is this true or not?

I believe it was something similar the schrödingers cat experiment was all about.

But since wikipedia is so bad at explaining things at an earthly level, could someone quickly say what schrödinger actually wanted to prove with his (non animal abusing) experiment?

 

[Wellsi]

http://realityshifters.com/pages/archives/jan04.html

its a site i was on looking around for an external explanation... i don't know the person that does it but apparently she has some credibility in the fact that she has published some books and does tours on life help or something... scroll down on the page to find out.

She reckons that to walk through a wall all you need to do is concentrate so hard on what is on the other side and not concieve that there is a barrier (in this case a wall) in between you and your destination. Sound like crap to you guys?

One more thing, i was attempting last night to piece together "degenerate matter" and the "Pauli exclusion principle". does anyone have an explanation that doesn't bust my head while trying to work it out. How are the two related?

 

[Wellsi]

Ok this is the webpage i used to find (or atleast attempted too) the definitions of the PEP and Degenerate matter. The explanations are brief and simple, i tried to use wikipedia but for me it was incomprehensible.

http://www.daviddarling.info/encyclopedia/P/Pauliep.html and
http://www.daviddarling.info/encyclopedia/D/degenmat.html

Does anyone have a more advanced link between the two other than what i wrote in a source anaylsis:
"These two articles are taken from the website of David Darling and explain reasons why it is impossible for one solid object to pass through another. The Pauli Exclusion Principle (PEP) allows for electrons to fill sub orbitals within the atoms electron clouds, but only two electrons can occupy each sub orbital. As no two electrons can occupy the same quantum state at the same place and time, there must be a differentiation between the electrons so they can both sit in the same sub orbital. This change is the change is spin. One electron will spin one way, one the other, thus they can both now occupy the same sub orbital. When another object comes to pass through, these outermost electrons on the atom repel each other (partly because they both have the same electric charge and cause like repels like in electrical and magnetic fields and partly because they must satisfy the PEP and none may occupy the same space time as other electrons. As there are only two different ways an electron can spin, the sub orbital, once full, cannot have more electrons pass through it.
This is why the PEP is relevant to putting one solid object through another. If great enough force is applied to compact the matter through which one is trying to pass, the solid object forms into “electron degenerate matter” which will resist anymore compression. Degenerate matter has every quantum state allowed by the PEP filled, and hence no matter will pass through this object.
Applying large amounts of force to a table will hence bend and compress the table in accordance to these two principles, but they will not allow a hand to pass through solid matter for these two reasons. "

Im not sure how correct it actually is. Would you guys care to analise it for me and make corrections.