Talk:Negative pressure

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Physics

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I think that the explanation of the term (negative pressure) should be based on the general understanding of words negative and pressure and so the description should start with an explanation why they are combined into something that seems neither negative nor pressure (e.g. "zero point" should be defined first). Otherwise it might create more confusion than elucidation and create in the minds of intelligent young people for whom wikipedia is made, a conviction that the physicists are nuts who don't know what they are talking about.

So please someone fix this page in such a way that an intelligent high school student won't be turned off from studying physics by the content of this page. It happens too often that misguided attempts to make physics a mysterious science (I know, "job security") turns intelligent young people away from becoming a physicst. I know that popularisation isn't easy if someone isn't Feynman but any physicists who has the time to do it should try it since the alternative is new Middle Ages. Please note that the great majority of humans still believe in ghosts (holy and otherwise) which isn't very safe for a democratic society (with its majority rule). Jim 14:29, 29 Dec 2004 (UTC)

How does the belief in God undermine physics? JD79 18:54, 25 March 2006 (UTC)[reply]

Science talks about nullification of hypotheses and the simplest valid theory. Most religions talk about faith in theories rather than experiments. The two are thus contradictory. In practice however, many scientists are also religious and have no real qualms about this as the religious part of their lives is independant of the science part. Unfortunately, some religious groups, particularly in the US, are confused and try to harm science to bolster their own weak beliefs. Now please go and troll on usenet or slashdot. --njh 22:29, 25 March 2006 (UTC)[reply]

I tried to provide some context - acooke, 20060909

Pressure vs Density[edit]

What's the difference between negative pressure and negative density? - Omegatron 00:52, May 2, 2005 (UTC)

pressure={\frac {force}{area}}

whereas

density={\frac {mass}{volume}}

. Pressure depends on the the force (how many particles there are, and how fast they're moving (i.e. how hot they are)), density depends on the total mass of the particles.

Unfinished pieces and inline comments[edit]

Moved from article source

example	atmospheres (bar)	kPa	Torr
sucking drink up a straw
vacuum cleaner
carburettor manifold

"Perhaps link to that video of the crab being sucked through the wall? Might be a bit gorey"

IMHO This is off track. All of the examples given above simply illustrate a difference in pressure "creating" a force (two forces that are unequal being resolved). The issue to me seems to be the concept of negative absolute pressure and I also can't get a handle on that. HOWEVER if the consensus of mathematicians and physicists is that there is such a thing then the rest of us have to do our best to grasp the concept. I imagine the mathematics is beyond more than a handful of people, and definitely way beyond me, so I must hope someone can put it into lay terms without losing the basics.
LookingGlass (talk) 21:52, 21 January 2008 (UTC)

vacuum in atmospheres[edit]

The article said that vacuum was -1 atm, which I changed to 0 atm. Now I realize that both are true. It's 0 atm absolute pressure, but -1 atm gauge pressure. Is that what was meant? — Omegatron 01:16, 31 March 2006 (UTC)[reply]

Yes. --njh 03:16, 31 March 2006 (UTC)[reply]

Redirect to Pressure#Negative pressures[edit]

I'm changing this disambiguation page to a redirect to Pressure#Negative pressures. The page previously listed 5 disambiguations:

negative pressure as opposed to positive pressure
vacuum
negative gauge pressure, a way of expressing pressure measurements below atmospheric pressure
suction
transpirational pull

But in actual fact, vacuum, suction and transpirational pull are all examples of negative gauge pressure. Seeing as this is all covered on the Pressure page anyway, I see no reason for this to be a separate disambiguation page. George Makepeace (talk) 12:26, 26 July 2013 (UTC)[reply]

Add negative pressure in cosmology[edit]

Add negative pressure in cosmology. — Preceding unsigned comment added by 2A02:587:4108:7600:89DF:4285:4839:6603 (talk) 06:54, 7 May 2017 (UTC)[reply]