SIGforum
Today's Science Problem
November 14, 2017, 12:01 AM
konata88Today's Science Problem
Slightly different question.
Is the answer above true always? Or only true if A is filled beyond a certain volume?
"Wrong does not cease to be wrong because the majority share in it." L.Tolstoy
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kkinaquote:
Originally posted by konata88:
Slightly different question.
Is the answer above true always? Or only true if A is filled beyond a certain volume?
It is definitely
not always true. The outcome can be altered with slightly different starting conditions. From the Wiki article...
quote:
At large extensions, the pressure inside a natural rubber balloon once again goes up. This is due to a number of physical effects that were ignored in the James/Guth theory: crystallization, imperfect flexibility of the molecular chains, steric hindrances and the like.[5] As a result, if the two balloons are initially very extended, other outcomes of the two-balloon experiment are possible,[1] and this makes the behavior of rubber balloons more complex than, say, interconnected soap bubbles.[4] In addition, natural rubber exhibits hysteresis: the pressure depends not just on the balloon diameter, but also on the manner in which inflation took place and on the initial direction of change. For instance, the pressure during inflation is always greater than the pressure during subsequent deflation at a given radius. One consequence is that equilibrium will generally be obtained with a lesser change in diameter than would have occurred in the ideal case.[1] The system has been modeled by a number of authors,[6][7] for example to produce phase diagrams[8] specifying under what conditions the small balloon can inflate the larger, or the other way round.
The answer is correct for the parameters I set forth in the OP.
November 14, 2017, 12:25 AM
Sig Sauer KrautHa. I guessed the correct answer. The way I thought about it was that a balloon usually gets easier to inflate once you get past a certain point. That, and I figured it was a trick question and would be the least obvious answer. :-)
November 14, 2017, 01:04 AM
kkina^^Excellent! If you watch the video, he gives what *may* be a clue when he inflates the larger balloon, taking obvious effort on the first breath, and a much easier time on the second exhale. Hard to tell if this was intentional or not.
You never know about those trick questions. Is he trying to smokescreen the obvious answer and make you pick the most bizarre choice, or is it really a tricker?
November 14, 2017, 01:25 AM
46and2quote:
Originally posted by Gustofer:
Answer B. Or...42.
Definitely 42.
(I guessed they'd equalize, too).
Cool problem.
November 14, 2017, 05:53 AM
zingoThere was a pretty good clue at the beginning of this.
quote:
Originally posted by kkina:
Two child's party balloons, initially identical....
But not identical any more. The balloon has changed.
November 14, 2017, 06:01 AM
Sig2340Then there's that there pervert equation to consider.
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November 14, 2017, 07:07 AM
RichNI had that happen once with a condom. Damn thing started expanding and almost sucked my testicals up inside me.
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November 14, 2017, 03:53 PM
flashguyI chose #4 (air flows from smaller to larger balloon) upon first reading the question (before reading any of the--initially incorrect--responses of others). I confess that I remember seeing a demonstration of the effect when I was in high school physics class in 1953.
flashguy
Texan by choice, not accident of birth November 14, 2017, 08:01 PM
Yellow JacketPersonally, I believe you're the victim of a hoax.
The part of the video where he opens the valve is actually running backwards. Notice that he carefully ensured that his face was not visible during that portion. It would be difficult to hide that his speaking wouldn't match the audio.
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Viet Nam '69-'70 November 14, 2017, 11:36 PM
kkinaquote:
Originally posted by Yellow Jacket:
Personally, I believe you're the victim of a hoax.
The part of the video where he opens the valve is actually running backwards. Notice that he carefully ensured that his face was not visible during that portion. It would be difficult to hide that his speaking wouldn't match the audio.
Google "2 balloon experiment". This is a well-known phenomenon. I doubt that there could be so many people in on a hoax.
As far as the video running backwards, where do you see that? Try searching this on Youtube; are all those videos running backwards?
November 15, 2017, 12:00 AM
BisleyblackhawkWhen the valve is opened between the two balloons...the larger balloon, due to its dominant nature, actually sucks the air out of the weaker smaller balloon...much the same way a cat (being the dominant creature) can suck the breath from a sleeping human (the weaker subservient creature)...it's just nature.
I actually expected them to balance out until both were approx. the same size...cool post

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November 15, 2017, 12:15 AM
oldRogerI can give you a real world example of the principles involved.
When repairing a bicycle tire you need to inflate the tube slightly to give it enough shape to get it into the tire to avoid a pinch flat. Care is required since the tube very definitely gets easier to inflate as you put more air into it. I use natural rubber tubes and it is very easy to blow one out, they will form a bulge, look like a cheap toy balloon and pop.
November 15, 2017, 12:31 AM
kkina^^Good example! Thinking about it, it does sound right when I had a bicycle.
November 15, 2017, 12:53 PM
KMitch200quote:
Originally posted by Bisleyblackhawk:
I actually expected them to balance out until both were approx. the same size...cool post
Yep, me too! Cool experiment.
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After the game, the King and the pawn go into the same box.
November 17, 2017, 03:18 AM
BuddyChrystAnyone who's made a poodle balloon animal should've been able to answer this correctly.
What? No one makes balloon animals???
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