# Probablity of Walking through a Wall

by Paul is Cool
Tags: probablity, walking, wall
 P: 2 Apparently, if all your particles are primed for tunnelling through a wall then you can walk through it, but the probability of all your particles tunnelling simultaneously is so low that you would have to attempt it more times than the age of the universe in years. Could someone please explain this to me. Thank-you very much.
 Emeritus Sci Advisor PF Gold P: 9,355 It's hard to answer when we don't know if you know anything about quantum physics already. For example, do you know what a wavefunction is? Would calculations make any sense to you? For now, let me just assure you that although the probability is non-zero, it is much, much, much less than you (or I) can even imagine. The probabilities we're talking about are typically less than 1/10^(10^30). As a comparison, the age of the universe, in seconds, is less than 10^19 seconds.
 P: 2,828 Welcome Paul_is_Cool if you wait long enough, diamonds will appear in your pocket. Maybe you should find an occupation for the meantime Maybe you know that QM is only about probability. Physicists gave up predicting A or B, they can just predict prob(A) or prob(B). Of course, this does not change the old classical physics, where prob(classical event) = 0.9999999999999............ and this = 1 for all purpose.
 P: 2 Thank you so much for that explanation; it was very enlightening. The truth is I'm actually doing this as part of a maths poster in order to show probability in an interesting way (a poster that says ' what's the chances of me appearing on the other side of a wall?' in bold lettering attracts people to read it).
Emeritus
PF Gold
P: 6,236
 Quote by Paul is Cool Apparently, if all your particles are primed for tunnelling through a wall then you can walk through it, but the probability of all your particles tunnelling simultaneously is so low that you would have to attempt it more times than the age of the universe in years. Could someone please explain this to me. Thank-you very much.
You know what really hurts ? When HALF of your particles tunnel through the wall. That probability is billions and billions of times higher than that ALL of them tunnel through...

cheers,
Patrick.
P: 27
 Quote by Paul is Cool The truth is I'm actually doing this as part of a maths poster in order to show probability in an interesting way (a poster that says ' what's the chances of me appearing on the other side of a wall?' in bold lettering attracts people to read it).

Paul, just make sure you say "what *are* the chances", and not "what is the chances", or "What is the chance?" singular. That whole subject-verb agreement thing can put a big dent in the impact of said poster.
At college, we had a pi-day. I was going to set up e-day the next year, (Feb 17), starting at 2:22 am (that's 1:82 base 60), but, well, I got sidetracked.

You may even want to put Vanesch's blurb about half of the atoms tunnelling, great visual.

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