Can anyone show me a diagram explaining negative pressure ,simply?

Answer 1

There is something called gauge pressure. This is the pressure above the atmospheric pressure. If the area you are in is less than the atmospheric pressure, it is considered negative pressure.

Answer 2

Yahoo Answers does not support diagrams...sorry.

But look at what pressure is. Its simply a net force (F) acting perpendicular over an area (A). In other words F/A = P (pressure in newtons per m^2 for example). If that force is directed away from the area, that would be negative pressure. If the net force is directed towards the area, that would be positive pressure.

A common example of negative pressure is the air pressure over the camber (top curved part) of an airfoil, like an aircraft wing. Here, due to something called the Bernoulli Effect, the net force is pulling upward on the wing and that's what keeps that airplane airborne. [See source.]

When air passes faster over the top of the wing due to camber than under the wing where there is no camber, there is more force under the wing than over it. The net force then is upward away from the top of the wing. Since that negative net force is operating over the area of the top, that is negative pressure.

Answer 3

i don't know of one offhand. and i'm to lazy to go surfing around XP. but negative pressure is actually really simple to explain ^^. its anything less then 760 mmHg, the pressure of our atmosphere. a vaccum tube in a tv has negative pressure in it. and if you take a straw, hold you finger on one end then suck on the other, bam... you just made negative pressure. XP