Can you turn a tire's inner tube inside out through a hole in its wall?
Article wrote:
This question, first posed by physicist Eric Voice in January, had many Physics World readers stumped. But what made the question harder was that readers were asked to find the solution using only their minds - without writing or drawing anything down. Voice reveals the answer in this month's issue, which includes photos of what happens when you try it for real. The question serves to show just how hard many people find it to visualize in three dimensions.
I say yes, but I'm having a hard time visualizing this (as predicted by the article).
I haven't looked up the solution yet, but when I find it, I'll try to post just the link and not the actual solution, to give everyone a chance to try this without a pre-set image to work from.
The hole must be big enough to accommodate the reversal.
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patiodog
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Mon 24 May, 2004 01:50 pm
I'm not so sure you can. It seems to me you'd have to pass the far side of the tube through the wall opposite the hole. But I'm having trouble with the image, too, so I'm not at all sure of my answer.
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fishin
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Mon 24 May, 2004 01:50 pm
I'd say "Yes".
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kuvasz
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Mon 24 May, 2004 01:59 pm
and that's different from turning your tee shirts inside out via the neck hole just how?
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BoGoWo
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Mon 24 May, 2004 02:01 pm
sure you can; but you are approaching a 'mobious' surface, along the way.
the hole only needs to be big enough to allow the constricted rubber to pass through.
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sozobe
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Mon 24 May, 2004 02:01 pm
Sure.
I do it when I sew pillows all the time.
Oh but wait it's a TUBE...
D'oh.
<squinching eyes...>
I still think you can, same principle. I can only visualize it halfway, though. Hole, fine. Reaching in and grabbing a piece of the tube on the inside and pulling it out, fine. I'm starting to think NO, that the bottom er hard to describe part stops it, the fact that it's connected.
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BoGoWo
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Mon 24 May, 2004 02:02 pm
and you are going to build a Murphy bed!???
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sozobe
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Mon 24 May, 2004 02:09 pm
I'm tellin' ya, I think it's no. I have to think about it more. If it were a sphere, no problem. But the tube -- oh, impossible to describe. Am really really wanting to go find an innertube and try it.
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BoGoWo
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Mon 24 May, 2004 02:10 pm
i guess your cycling days are numbered!
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patiodog
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Mon 24 May, 2004 02:11 pm
Thinking about it this way: if you severed the tube completely and turned it inside out, you'd have to fold the entire lip back and pull it over the tube. This is impossible if you fail to sever the tube completely, ergo it is impossible to turn the tube inside out just be making a hole in it. Making a hole, after all, is the same as failing to cut all the way through.
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sozobe
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Mon 24 May, 2004 02:22 pm
Hey, great explanation.
I'm certain of "no." You can turn some of it inside out, but not all of it... my halfway thing. In other words, you can't end up with an inside-out innertube that looks like an innertube, (a donut) you end up with a halfway inside out thing (an eclair).
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BoGoWo
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Mon 24 May, 2004 02:23 pm
wrong; visualize a donut (same problem different scale) made of thin rubber, now cut a fairly large hole in one side, and pull the opposite wall through; continue, until all is through!
hmmmm now i'm not so sure
thinking (this may take some time........)
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BoGoWo
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Mon 24 May, 2004 02:24 pm
yup, it has an outside surface, and an inside surface, so from the hole you can reverse the entire outside to inside.
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patiodog
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Mon 24 May, 2004 02:27 pm
Hmmm... As you pull the inside surface through the hole, you are closing the loop -- the donut hole is disappearing. I don't think you can pull it through with the inside equator is intact.
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rosborne979
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Mon 24 May, 2004 02:28 pm
cicerone imposter wrote:
The hole must be big enough to accommodate the reversal.
I think the problem assumes the elasticity of the inner tube is sufficient to accomodate the physical material (it's a topology problem using a common item as an example).
(or maybe you were just being facetious... if so, sorry CI )
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BoGoWo
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Mon 24 May, 2004 02:29 pm
kids - don't try this at home!!
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BoGoWo
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Mon 24 May, 2004 02:31 pm
o.k. i just did it; it works!!
now haw am i going to get this f----ing thing back on my bike?
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rosborne979
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Mon 24 May, 2004 02:34 pm
patiodog wrote:
Thinking about it this way: if you severed the tube completely and turned it inside out, you'd have to fold the entire lip back and pull it over the tube.
Yeh, this is the way I started thinking about it. But I can't quite visualize the last little segment coming through as the tube is finally inverted... ugh.
patiodog wrote:
This is impossible if you fail to sever the tube completely, ergo it is impossible to turn the tube inside out just be making a hole in it.
Is this true? Is it impossible to to invert the tube if you fail to sever it completely? If so, then I believe you have the correct answer, but I'm not certain that it's impossible.
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sozobe
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Mon 24 May, 2004 02:36 pm
I'm certain enough to make a bet. Any takers? (No, you cannot turn an innertube all the way inside out.)
)
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