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Author Topic: Drinking Straw Question??  (Read 10682 times)

Offline edcase

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Drinking Straw Question??
« on: 07/02/2006 17:36:42 »
This may be a stupid question as im not all up on science.
Me and some friends were argueing whether a straw that is about 10 miles long could be used for drinking?
Could the air pressure etc still be able to force the drink from 10 miles away up the straw?.
Obviously we knew you couldnt do it in one breath, but by holding a finger over the straw end, it doesnt allow air pressure to escape and so the water would stay in the straw (like when you try it with a normal straw and some water). So by doing this could you eventually get the water to travel the 10 miles?

Hope its not to much of a silly question, just curious.


 

Offline edcase

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Re: Drinking Straw Question??
« Reply #1 on: 07/02/2006 17:39:39 »
OOps sorry its seemed to posted twice. Not sure how to delete this post
 

Offline neilep

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Re: Drinking Straw Question??
« Reply #2 on: 07/02/2006 17:53:06 »
quote:
Originally posted by edcase

OOps sorry its seemed to posted twice. Not sure how to delete this post



That's ok Joe...I deleted the other one for you.

What a great question !...I don't know the answer and I'm just not ready to stick all the straws in my house together and then buy some more to make up ten miles !:D

My gut instinct is to say yes...if you suck on on end then it seems logical to assume that liquid will be drawn into it from the other end.

Lets hope a passing ' ten mile straw suction ' expert passes by and answers.:)

Men are the same as women.... just inside out !!
 

Offline rosy

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Re: Drinking Straw Question??
« Reply #3 on: 07/02/2006 18:14:10 »
It's going to depend on whether you're sucking *up* the straw or along it.
About 10m is the normal limit that atmospheric pressure can push water if there's a void above it... so even if you've sucked every air molecule out of the straw you won't get it above that. And anyway, the pressure difference between outside and inside would collapse a conventional drinking straw long before that.
10 miles along a gentle incline would be possible in principle, given a stiff enough straw... but you'd be limited to a rise of less than 1m/mile which could be an engineering challenge!
 

Offline Ray hinton

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Re: Drinking Straw Question??
« Reply #4 on: 07/02/2006 20:44:13 »
I TAKE IT FROM THIS QUESTION, THAT YOU LIVE TEN MILES FROM THE BREWERY !!!

RE-HAB IS FOR QUITTERS.
 

Offline edcase

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Re: Drinking Straw Question??
« Reply #5 on: 08/02/2006 17:44:32 »
LOL, damn you figured me out.
 

Offline daveshorts

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Re: Drinking Straw Question??
« Reply #6 on: 11/02/2006 15:30:28 »
If you are sucking very pure water with no dissolved gasses you can suck up more than 10m but the situation is unstable and if a bubble forms it will grow bigger and bigger as the water boils until it gets back to about 10m height. This is how trees can suck water up their xylae even though they are more than 10m high. In most cases however the 10m limit stands.
 

Offline Andrew K Fletcher

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Re: Drinking Straw Question??
« Reply #7 on: 11/02/2006 17:00:36 »
Sorry Dave, but you can't suck water up a tube more than 10m no matter how dissolved gas free the water is in the tube, because you still have the cavity in front of the rising water level which no amount of sucking can address. so your statement "if a bubble forms" is not correct either, because you have still got to get around the space above the water which is your equivalent to a bubble already formed.

And this is precisely why the cohesion tension theory fails, because the tree cannot draw water up in this manner any more than you can suck water up a tube from the top. Cavitation is known to take place in trees, but it does not stop the circulation. It would stop the circulation if the tree used the current erroneous cohesion tension theory to lift water.

Andrew

quote:
Originally posted by daveshorts

If you are sucking very pure water with no dissolved gasses you can suck up more than 10m but the situation is unstable and if a bubble forms it will grow bigger and bigger as the water boils until it gets back to about 10m height. This is how trees can suck water up their xylae even though they are more than 10m high. In most cases however the 10m limit stands.



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
 

Offline daveshorts

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Re: Drinking Straw Question??
« Reply #8 on: 12/02/2006 11:02:37 »
Sorry everyone else:
Andrew, your own experiments have prooved that you can (he has syphoned water over 10m) deal with it.
 

Offline Ottehg Star

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Re: Drinking Straw Question??
« Reply #9 on: 12/02/2006 11:21:01 »
if you wanted to try and suck the drink 10 miles along a straw dont forget to get a really big glass because thats just over 250 cubic metres (off the top off my head) of coca cola you gonna be sucking up,
 

Offline Andrew K Fletcher

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Re: Drinking Straw Question??
« Reply #10 on: 12/02/2006 14:58:46 »
Sorry Dave, The experiment at Brixham does not siphon water, it causes water to flow in a circular direction in a n shaped tube, giving the appearance of a syphon effect, but the flow rate differs somewhat to a siphon effect, and at lower levels than ten metres using the same inverted U tube, it is possible to observe the flow rate of the saline and compare with the flow rate of a siphon triggered in the same tubing. There is a marked difference to the way the water behaves. Trust me on this Dave. Or conduct the simple experiment yourself and compare.


Andrew

quote:
Originally posted by daveshorts

Sorry everyone else:
Andrew, your own experiments have prooved that you can (he has syphoned water over 10m) deal with it.



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
« Last Edit: 12/02/2006 15:11:23 by Andrew K Fletcher »
 

Offline daveshorts

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Re: Drinking Straw Question??
« Reply #11 on: 12/02/2006 17:55:03 »
again sorry everyone else this is a long running discussion. Andrew has set up a syphon over 10m high using boiled water and instead of making one arm heavier by making it longer he has injected saline solution into it causing a flow to be established:

Andrew
You are correct that you can't suck up more than 10m if there is a bubble at the top, but if there is not (eg something like a syringe completely filled with water at the top) as your experiments show a column can exist that is more than 10m high and therefore you can apply slightly more force with the syringe and the water will move up.

What is the difference in the way the water behaves? If you want to persuade a physicist that something interesting is going on you will have to show them numbers, and do some maths to show that it is not explained by current theories.
 

Offline rosy

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Re: Drinking Straw Question??
« Reply #12 on: 12/02/2006 18:43:11 »
Oh lord, here we go again..

Andrew:
Presumably when you were making your measurements you took some notes on what you observed so...
what was the height of the column?
how much saline (what volume, what concentration/density) did you inject?
what was the (approximate) flow rate? how did you measure it?
did you carry out the experiment at a range of heights (above and below the 10m cut-off)?
did you do parallel experiments (at the same height) for a conventional syphon and for your saline system? how much saline was injected? what was the height difference between the syphon arms? what was the flow rate of each system?
have you compared flow rates for open (conventional syphon like) and closed (loop) systems for the injection of saline solution?

From your post above it's clear you've carried out the experiments so you presumably have the data and can (and presumably have done) the calculations which would establish the truth of your assertions about the difference in flow rate.

The point about science is that one person does the experiment and then provides their conclusions *along with the data* which would allow colleagues to check that those conclusions are supported. It shouldn't be necessary for each person to carry out an experiment, but none of the posts I've read by you on this subject (or your website, last time I looked) carried this data.

Please.. produce it!
 

Offline Andrew K Fletcher

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Re: Drinking Straw Question??
« Reply #13 on: 15/02/2006 18:42:17 »
Dave, your syringe analogy does not work, even with boiled water. For example, I came up with the idea of including a valve at the top of the U tube, using rubber ring compression joints, with good airtight seals.
The addition of the valve, via a T piece, caused the formation of a cavity and the collapse of the water columns at the same level that the perfect complete tube succeeded.

The reason being, is in your vertical tube analogy with a syringe at the top, will inevitably fail, because you are relying on the adhesive qualities of water to maintain the column of water inside the tube, by sticking to the syringe plunger. This cannot and will not work. For example, mercury was used in the same experiment and failed, producing a cavity above the mercury.

Rosy, yes, I have conducted the experiments many times using varying amounts of concentrations of salt, sugar, tea, urine, milk, liquidized leaves from a tree, fruit juice etc. No matter what the concentration is, the flow still occurs. admittedly, there appears to be a varying rate of flow initially.

But you must also remember that as soon as the salt solution or any other solution is added, it instantly gets diluted by the volume of water in the downward flowing side.

It would also appear from observing the flow at lower levels against the flow above ten metres, that some additional acceleration of the flow occurs at the higher levels.

as for comparing the flow rate to a siphon, at 24 metres or less, the siphon simply does not work over the ten metre level.

I do not have a website.

Finally, no matter what maths, stats, video evidence, television news footage, school experiments, Invention fair exposure, these experiments receive, you or your colleagues for that matter will still remain unconvinced, no matter how much evidence is before you.

The experiments are childishly simple and beautiful to observe, and have convinced all who stand before them. Everyone on this site has an interest in science, yet, how many of you have even thought about repeating the bench top model and investigating this new paradigm for circulation?

Answer of course is: Not a single one of you! You would rather send me away to do some more homework and keep me quiet and off your back.

Have you any idea how frustrating it is to keep hearing we are not convinced, we are sceptical, and worst of all, we can't be bothered to test it for ourselves because there is nothing in it for us.

But I promise you this, before I die, I will shove these tubes so far up the ass of science, it will have to rush to the toilet and empty all of its bullshi-t down the pan.

RE:
You are correct that you can't suck up more than 10m if there is a bubble at the top, but if there is not (eg something like a syringe completely filled with water at the top) as your experiments show a column can exist that is more than 10m high and therefore you can apply slightly more force with the syringe and the water will move up.

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
 

Offline rosy

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Re: Drinking Straw Question??
« Reply #14 on: 15/02/2006 21:23:02 »
quote:
The reason being, is in your vertical tube analogy with a syringe at the top, will inevitably fail, because you are relying on the adhesive qualities of water to maintain the column of water inside the tube, by sticking to the syringe plunger. This cannot and will not work. For example, mercury was used in the same experiment and failed, producing a cavity above the mercury.

That seems reasonable but not surprising. Water will stick better to some materials than to others. From my own experience I know that water spreads out better on (and therefore adheres better to) common or garden plastic tubing than it does to a common or garden plastic syringe, you can see this from how a drop of water behaves on each. Certainly I'd expect if you introduced a plastic surface to which water doesn't adhere very well that would trigger the cavitation event you need for the water to fall back to the vacuum level.

quote:
Rosy, yes, I have conducted the experiments many times using varying amounts of concentrations of salt, sugar, tea, urine, milk, liquidized leaves from a tree, fruit juice etc. No matter what the concentration is, the flow still occurs. admittedly, there appears to be a varying rate of flow initially.

Yes. Numbers please. Densities of the fluids injected and rates of flow. Of course they'll be diluted as soon as they're injected but you'll still have the same amount of initial potential energy increase from introducing a higher density liquid high up.

quote:
as for comparing the flow rate to a siphon, at 24 metres or less, the siphon simply does not work over the ten metre level.

How did you set up the siphon? (Use a U of tube and then move one end? Fill up the container at the bottom of one of the tubes and see whether the levels equalised? How long did you observe the system for (I'd expect it to take a while for the pressure changes to equalise out over a long length of even very slightly elastic tube (certainly anything bendy enough to fill with water and then raise 10m plus).
Just saying the siphon didn't work is uninformative. If I know what you did then I can figure out if I'm wrong that all your observations can be explained by conventional physics, as I believe, or not, as you believe.

quote:
I do not have a website.

Clearly I was mistaken, but nine months or so ago, last time we had this discussion, you linked to a web page (I think it had a sort of brown-ish background) which I was under the impression you were involved with. It had a load of stuff about gravity and trees on it.

quote:
Finally, no matter what maths, stats, video evidence, television news footage, school experiments, Invention fair exposure, these experiments receive, you or your colleagues for that matter will still remain unconvinced, no matter how much evidence is before you.

And so on.
Um, I don't know about my "colleagues", but I'm genuinely interested, or I wouldn't be pursuing this. But you still haven't given me the very specific information I've asked you for and you seem to imply you've collected.
I don't doubt what you say about your results, but all you give us is conclusions not data. If you want to be taken seriously by the "scientific community" you have to play by its rules. If not, why are you bothering to be abusive?
You need to realise that the science doesn't need a new theory except to account for results that can't be explained in terms of existing theories. Since, qualitatively, your results appear to be entirely explicable in terms of standard physics if you believe that they are quantitatively different you will have to provide all the calculations backed up by the numerical measurements on which they are based and  detailed experimental protocols.
 

Offline ariel

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Re: Drinking Straw Question??
« Reply #15 on: 18/02/2006 16:29:17 »
ok well, i used to stick the ends of straws together to make these 4 straw long super straws....and i found it harder to drink...
so i guess making a super super super long straw...would be super super super hard to sip.
(ahh but these were with rather large straws....if i used coffee stirrers...i bet i could make it much longer!)
 

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Re: Drinking Straw Question??
« Reply #15 on: 18/02/2006 16:29:17 »

 

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