| Topic: |
Science > Physics |
| User: |
"Lisa Goose" |
| Date: |
04 Jun 2006 10:37:22 AM |
| Object: |
physics |
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| User: "T Wake" |
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| Title: Re: physics |
04 Jun 2006 11:34:35 AM |
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"Lisa Goose" <me@privacy.net> wrote in message
news:6hv5821gcjdq68g9ki4h0cgicrfl2ltph0@4ax.com...
sucks
Cool. But that is of secondary importance to the bigger question. Do you?
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| User: "Phineas T PuddleDuck" |
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| Title: Re: physics |
04 Jun 2006 10:46:19 AM |
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In article <6hv5821gcjdq68g9ki4h0cgicrfl2ltph0@4ax.com>,
Lisa Goose <me@privacy.net> wrote:
sucks
rocks
--
The greatest enemy of science is psuedoscience.
Thats Mr Puddleduck to you, k00k!
Laughing at physics kooks and cranks for over ten years now.
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| User: "The Ghost In The Machine" |
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| Title: Re: physics |
04 Jun 2006 02:00:06 PM |
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On Sun, 04 Jun 2006 16:37:22 +0100, Lisa Goose wrote:
sucks
Physics cannot possibly suck. Take an ordinary soda can and a straw, and
suck in the more or less usual manner. What is happening?
Atmospheric pressure, that's what happening.
If you can, get a straight soda straw of about 10m in length (or, more
likely, some flexible plastic tubing), place the can at an appropriate
spot, go up a ladder (or a second or third story window!) and see if you
can still suck water from that can of soda.
A probably more practical experiment, especially if the tubing is
transparent, is to fill that tube with water, cap one end (I wouldn't
recommend a finger for this), then upend the tube carefully into a water
reservoir and observe what happens. (It's probably easier to use a heavier
liquid such as mercury. 10 meter tubes are very unwieldy. :-) )
--
#191,
It's still legal to go .sigless.
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| User: "The Sorcerer" |
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| Title: Re: physics |
04 Jun 2006 07:47:42 PM |
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"The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
news:pan.2006.06.04.18.35.21.91153@earthlink.net...
| On Sun, 04 Jun 2006 16:37:22 +0100, Lisa Goose wrote:
|
| > sucks
|
| Physics cannot possibly suck. Take an ordinary soda can and a straw, and
| suck in the more or less usual manner. What is happening?
|
| Atmospheric pressure, that's what happening.
|
| If you can, get a straight soda straw of about 10m in length (or, more
| likely, some flexible plastic tubing), place the can at an appropriate
| spot, go up a ladder (or a second or third story window!) and see if you
| can still suck water from that can of soda.
|
| A probably more practical experiment, especially if the tubing is
| transparent, is to fill that tube with water, cap one end (I wouldn't
| recommend a finger for this), then upend the tube carefully into a water
| reservoir and observe what happens. (It's probably easier to use a heavier
| liquid such as mercury. 10 meter tubes are very unwieldy. :-) )
|
Ok, can I have a blow-job? (Females only need apply)
Androcles
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| User: "Henning Makholm" |
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| Title: Re: physics |
04 Jun 2006 08:26:47 PM |
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Scripsit The Ghost In The Machine <ewill3@earthlink.net>
On Sun, 04 Jun 2006 16:37:22 +0100, Lisa Goose wrote:
sucks
Physics cannot possibly suck. Take an ordinary soda can and a straw, and
suck in the more or less usual manner. What is happening?
As a matter of definition, what does "suck" mean here?
It should be fairly easy to create negative pressure in an appropriate
solid body, but perhaps "suck" ought to be restricted to fluids. The
tensile strength of water before cavitation sets in is rather
pitiable, but is there anything that _in principle_ prevents a fluid
from sustaining a negative pressure?
--
Henning Makholm "Det er jo svært at vide noget når man ikke ved det, ikke?"
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| User: "Edward Green" |
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| Title: Re: physics |
04 Jun 2006 08:51:28 PM |
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Henning Makholm wrote:
Scripsit The Ghost In The Machine <ewill3@earthlink.net>
On Sun, 04 Jun 2006 16:37:22 +0100, Lisa Goose wrote:
sucks
Physics cannot possibly suck. Take an ordinary soda can and a straw, and
suck in the more or less usual manner. What is happening?
As a matter of definition, what does "suck" mean here?
It should be fairly easy to create negative pressure in an appropriate
solid body, but perhaps "suck" ought to be restricted to fluids. The
tensile strength of water before cavitation sets in is rather
pitiable, but is there anything that _in principle_ prevents a fluid
from sustaining a negative pressure?
No. And the tensile strength of water in a clean capillary tube (no
nucleation sites for vapor) is rumored to be un-pitiable.
There is the famous problem of how water can passively climb to the top
of tall trees by capillary action, given the limitation of cavitation.
Two posibilities are that the process is not passive, but the water is
pumped up by the roots, _or_ that the water is actually in tension at
least part of the way. Or both.
To this I add my own third screwball theory, that water in very thin
capillaries with highly hydrophilic walls does not act like bulk water,
but is locally supported by the wetable surface. It's all surface
layer, no bulk.
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| User: "Edward Green" |
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| Title: Re: physics |
07 Jun 2006 06:42:10 PM |
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Edward Green wrote:
There is the famous problem of how water can passively climb to the top
of tall trees by capillary action, given the limitation of cavitation.
Two posibilities are that the process is not passive, but the water is
pumped up by the roots, _or_ that the water is actually in tension at
least part of the way. Or both.
Oops. I got the root pressure part wrong. Root pressure could either
be purely passive (osmotic pressure), or aided by active processes.
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