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#1
04-24-2012, 11:00 PM
 The Flying Dutchman Guest Join Date: Nov 2000
Sucking, and I don't mean through a straw

We all know the scientific mechanism that allows us to suck liquids through a straw, but what about sucking in a limp spaghetti noodle ? I can't believe that atmospheric pressure can push that limp noodle into my pursed lips any more that I can push my limp...............
#2
04-24-2012, 11:08 PM
 Carptracker Guest Join Date: Jan 2009
Quote:
 Originally Posted by The Flying Dutchman I can't believe that atmospheric pressure can push that limp noodle into my pursed lips ..
Believe it. It does. Why can you not believe this?
#3
04-24-2012, 11:44 PM
 Trinopus Member Join Date: Dec 2002 Location: San Diego, CA Posts: 7,164
Quote:
 Originally Posted by Carptracker Believe it. It does. Why can you not believe this?
It's a little counter-intuitive, especially when we think of forces involving linear vectors passing through the center of mass of the object being accelerated. The idea of a whole lot of little forces being "toe-nailed" (illustration for disambiguation re toe- and finger-nails) takes a kind of leap of visualization. We're more accustomed to the "billiard ball" model of forces and acceleration.
#4
04-25-2012, 07:22 AM
 cornflakes Charter Member Join Date: Aug 1999 Location: Bubbaville Posts: 4,456
Quote:
 Originally Posted by Trinopus It's a little counter-intuitive, especially when we think of forces involving linear vectors passing through the center of mass of the object being accelerated. The idea of a whole lot of little forces being "toe-nailed" (illustration for disambiguation re toe- and finger-nails) takes a kind of leap of visualization. We're more accustomed to the "billiard ball" model of forces and acceleration.
Why wouldn't air molecules be pushing the other way after interactions with the molecules of our lips?
#5
04-24-2012, 11:16 PM
 beowulff Member Join Date: May 2001 Location: Scottsdale, more-or-less Posts: 9,703
It's not pushing from the end, like your limp...
The spaghetti is being pushed from all over, especially right near your lips.
#6
04-24-2012, 11:25 PM
 Dewey Finn Charter Member Join Date: Apr 2003 Posts: 14,739
Some of your questions might be answered in this Straight Dope column.
#7
04-24-2012, 11:40 PM
 cornflakes Charter Member Join Date: Aug 1999 Location: Bubbaville Posts: 4,456
Cecil kinda covered this one. Personally, I think that the spaghetti is pulled in by the difference in pressure between the atmosphere and inside your mouth. If I'm doing the math right, sucking on a 1/16 inch thick strand of spaghetti should pull the strand into the mouth with about 1/10 ounce of force (I'll leave it to someone else to test this. )
#8
04-25-2012, 08:54 AM
 zut Charter Member Join Date: Apr 2000 Location: Detroit, MI Posts: 3,594
Quote:
 Originally Posted by cornflakes Cecil kinda covered this one.
Yes he did, and gave a particularly shitty answer.

Previous threads on this subject may be useful:
Fishy Spaghetti Explanation (1/2008)
Spaghetti Physics (12/2000)
#9
04-25-2012, 12:00 AM
 Gary "Wombat" Robson Vombatus Moderatus Moderator Join Date: Mar 2003 Location: Montana, U.S.A. Posts: 9,444

[moderating]
Since Cecil covered this, I've moved the thread to "Comments on Cecil's Columns" for further discussion.
[/moderating]
__________________
Everything in moderation!
#10
04-25-2012, 09:58 AM
 penumbrage Guest Join Date: Jan 2008
Quote:
 Originally Posted by The Flying Dutchman We all know the scientific mechanism that allows us to suck liquids through a straw, but what about sucking in a limp spaghetti noodle ? I can't believe that atmospheric pressure can push that limp noodle into my pursed lips any more that I can push my limp...............
Can you believe you can suck spaghetti through a (close fitting but not tight) straw?
Can you believe it still works even if the straw is just 1/4 inch long and form fitting to the pasta?
I'm afraid I can't help you with your other problem, you'll either have talk your significant other into sucking or shop around for a new one who will.
#11
04-25-2012, 10:13 AM
 The Flying Dutchman Guest Join Date: Nov 2000
Here's what I think.

Close your mouth and with a noodle of spaghetti starting from the front of your mouth, you can pull it through with your tongue and the roof of your mouth to the rear. Care must be taken to not over tension the noodle or it will pull apart.
No atmoshere is involved.

Really, I just figured it out.

Of course we can not apply tension to liquids, but we can with solids.
#12
04-25-2012, 01:40 PM
 Powers Charter Member Join Date: Jun 1999 Location: Rochester, NY, USA Posts: 838
Look, we can solve this by simple experiment. Place a human being and a plate of spaghetti in a vacuum chamber and see if he or she can still suck a strand up.

Powers &8^]
#13
04-25-2012, 02:51 PM
 davidm Charter Member Join Date: Mar 2002 Location: Near Philadelphia PA, USA Posts: 5,642
Place someone in some kind of pressure chamber, have them seal their lips around a piece of spaghetti, then increase the pressure. I don't think the spaghetti will slither into their mouth.
#14
04-25-2012, 02:59 PM
 davidm Charter Member Join Date: Mar 2002 Location: Near Philadelphia PA, USA Posts: 5,642
On a more serious note, do the above with a test tube with a rubber stopper. Drill a spaghetti size hole in the stopper, and place a wet piece of cooked spaghetti through the hole so that most of it is still hanging outside of the test tube.

suspend the whole thing spaghetti down in a pressure chamber, then increase the pressure and see if the spaghetti is sucked into the test tube.

#15
04-25-2012, 09:12 PM
 Trinopus Member Join Date: Dec 2002 Location: San Diego, CA Posts: 7,164
Quote:
 Originally Posted by davidm Place someone in some kind of pressure chamber, have them seal their lips around a piece of spaghetti, then increase the pressure. I don't think the spaghetti will slither into their mouth.
Um... Why not? It seems to follow logically. It would certainly work that way with a cup of soda and a straw.

And, actually, both this and the vacuum chamber experiment are feasible...
#16
04-26-2012, 09:53 AM
 Happy Lendervedder Guest Join Date: Dec 2001
Quote:
 Originally Posted by The Flying Dutchman We all know the scientific mechanism that allows us to suck liquids through a straw, but what about sucking in a limp spaghetti noodle ? I can't believe that atmospheric pressure can push that limp noodle into my pursed lips any more that I can push my limp...............
...noodle into your wife's pursed lips.

Sorry, that adds nothing to the conversation but I had to finish the thought.
#17
04-26-2012, 11:22 AM
 Irishman Guest Join Date: Dec 1999
Quote:
 Originally Posted by davidm Maybe it's the air pressure on the back of your head?
This is where an experiment needs to be devised that makes two hard-mounted fixtures, one of which creates suction and presses up against the other one. And we need some kind of force gauge to measure the suction force.

Quote:
 As for sucking on your hand, don't your bodily fluids have pressure? Those pressures are presumably in stasis with the air pressure, so when the air pressure on a portion of your hand is reduced, the fluid pressures push it out.
That is an excellent point. The interior forces of the material in question are also part of the issue. That is why I shifted the example to a hard object like a cabinet or wall, something that does not have fluid inside that can deform easily.

This is definitely a thought provoking topic.
#18
04-26-2012, 02:57 PM
 zut Charter Member Join Date: Apr 2000 Location: Detroit, MI Posts: 3,594
A suction cup has a little hollow between the cup and the surface. When you push on the cup, the hollow flattens and pushes air out. When you relax, the cup springs back, increasing the size of the hollow and decreasing the pressure within. The circumference of the suction cup creates a seal that (for a reasonable length of time) maintains the lower pressure within the hollow.

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