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…

Believe it. It does. Why can you not believe this?

It’s not pushing from the end, like your limp…
The spaghetti is being pushed from all over, especially right near your lips.

Some of your questions might be answered in this Straight Dope column.

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. :slight_smile: )

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.

[moderating]
Since Cecil covered this, I’ve moved the thread to “Comments on Cecil’s Columns” for further discussion.
[/moderating]

Why wouldn’t air molecules be pushing the other way after interactions with the molecules of our lips?

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)
[url=The Spaghetti Incident? - Cecil's Columns/Staff Reports - Straight Dope Message Board]The Spaghetti Incident? (12/1999)

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.

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.

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^]

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.

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.

Anyone have access to equipment this could be done with?

Maybe this is something that could be suggested to Mythbusters.

Thinking about this anew…

Take something thick but soft, like the palm of your hand, and hold it up to your lips. Begin sucking. You will notice an inclination for the skin to pull into the mouth through the lips. This does not on the face of it seem to be by external air pressure pushing the skin into the mouth. The hand is fairly thick, and the tissue soft enough but bones rigid enough that it does not seem to be the same as if a thin, flexible membrane were held to the opening.

So what causes the movement? It is tempting to say that the suction creates a pulling force. But how does that work?

Suction is created by inhaling, which expands the lungs, and creates a larger volume for the air that is in the mouth/lung system. If the opening of the mouth and nose is sealed, the result is the same amount of air in a much larger space, or a lower air pressure. Why does this lower air pressure pull on the material over the opening?

If the mouth opening is sealed with a thin membrane, it is easy to say that the suction is really the pressure difference inside the mouth vs outside air, and the movement comes because the external air pushes the membrane into the opening.

But take a thick, rigid surface that is solidly mounted, like a wall or an item of furniture. Now put your mouth up to the surface (feel free to clean the surface to your content prior to this exercise). You create a suction force that holds the mouth to the surface without the surface moving. The rigid nature of the surface means it is not being deformed, and the solid mounting means that air pressure on the far side is irrelevant. What causes the force that secures your mouth to the surface, the “suction”?

Maybe it’s the air pressure on the back of your head?

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.

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…

Yes, but not intuitively.
Powers &8^]

…noodle into your wife’s pursed lips.

Sorry, that adds nothing to the conversation but I had to finish the thought.