The discussion centers on the mechanics of a Torricelli barometer, specifically how a vacuum at the top of the tube influences the movement of liquid, such as mercury. Participants clarify that the vacuum does not exert a force; rather, atmospheric pressure pushes the liquid up into the vacuum. The vacuum is created when the tube is inverted after being filled with liquid, and the height of the liquid column is determined by the external atmospheric pressure, which is approximately 760 mm for mercury at one atmosphere. The conversation emphasizes that vacuums do not "suck" but are a result of pressure differentials.
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CollinsArg said:Hello! When a torricelli barometer is made there is a vacuum at the end of the top of the tube, does this vacuum exert a force to the water or mercury to go up?
It's not clear what you mean here. All vacuums have the same absolute pressure: zero.and how is that it can be a bigger vacuum depending on the air preassure? How does it exactly work? Thanks.
I mean, this force as an absorbent force like the contrast of natura force(?SteamKing said:How can a vacuum exert a force? A vacuum means there's nothing there.It's not clear what you mean here. All vacuums have the same absolute pressure: zero.
What would happen to your barometer if there were no vacuum in the end of the tube, and the liquid (water, mercury, whatever) tried to climb into the top of the tube?
I'm not sure I understand the distinction. A force is a force. What is the liquid in the barometer tube being absorbed into?CollinsArg said:I mean, this force as an absorbent force like the contrast of natura force(?
the top of the tube which is closed is empty, so there is a vacuum there, below there is water, but when the atmospheric preassure decrease the vacuum becomes bigger and the water decrease its level in the tube.SteamKing said:I'm not sure I understand the distinction. A force is a force. What is the liquid in the barometer tube being absorbed into?
CollinsArg said:the top of the tube which is closed is empty, so there is a vacuum there, below there is water, but when the atmospheric preassure decrease the vacuum becomes bigger and the water decrease its level in the tube.
I've seen videos with vacuum chambers that absorb the air and it produce like a "force" that suctions X thing.
So why the vacuum in a barometer is produced and why its force is weak(? :P
Pressure! Sorry, English is not my mother tongue and I'm learning it! I'm from Argentina hehe..SteamKing said:If nothing else, please learn to spell 'pressure' correctly.
It's not clear what you mean when you say the vacuum becomes 'bigger'. Since a vacuum is already nothing, does this mean it becomes more 'nothing'?
A simple barometer is made by taking a tube of sufficient length and then filling it completely with liquid, so that no air or other gas remains trapped inside. Once the tube is filled and no gas is left trapped, the open end of the tube is closed and the tube is then inverted. The end of the tube is placed in a dish or bowl which contains additional fluid, which will mix with the liquid in the tube once the lower end is opened.
https://en.wikipedia.org/wiki/Evangelista_Torricelli
The reason the fluid level in the tube drops and creates a vacuum in the tip is that atmospheric pressure from the outside of the tube is trying to balance the pressure created inside the tube by the column of liquid remaining there. If the tube is filled with mercury and there is 1 atmosphere of pressure on the outside, the top of the mercury column inside the tube will be exactly 760 mm higher than the level of the fluid in the dish or bowl. This is an illustration of Pascal's law:
https://en.wikipedia.org/wiki/Pascal's_law
You've been looking at the barometer all wrong. The vacuum in the tip is created when the filled tube is inverted. The fluid isn't pulled up by some mysterious force located in the top of the tube. The outside atmospheric pressure pushes the fluid up into the vacuum in the tip, because there is nothing in the tip to resist the fluid being pushed up by the atmosphere outside.
I don't know about these videos you are viewing. I do know that there is no such thing as an 'absorbing' force.CollinsArg said:Pressure! Sorry, English is not my mother tongue and I'm learning it! I'm from Argentina hehe..
I understand what you are saying but what I mean is:
I see too realities, the one that you have just said, that there is nothing there and that nothing doesn't do anything indeed. And a reality that there is a nothing that does do something, and I saw it in some videos for ejample "video". So why is it that in the video the nothing has an "absorbing force", but in the vacuum of the barometer nothing seems to do that vacuum, and even though it can be bigger or not (yeah to become more nothing) :). Thank you
i left the link u just have to press where it says video in blue colourSteamKing said:I don't know about these videos you are viewing. I do know that there is no such thing as an 'absorbing' force.
DrClaude said:I haven't looked at the entire video, but it looks very-well made. The presenter clearly explains, for instance in the sequence staring at 2:17, that is is the air left at the top of the vial that is pushing the liquid out.
Vacuums don't suck.