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Old 31st July 2020, 09:02 AM   #1
Pixie of key
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25 liter glass bottle upside down. Inside the bottle 12 l. water. negative pressure

25 liter glass bottle upside down. Inside the bottle 12 l. Of water. The negative pressure. The bottle jerks down and protrudes 35 cm. upwards when air pushing inside bottle.

https://youtu.be/vzblIc2OaSs

Why does the bottle move first downwards and only then upwards? When air is pushed inside the bottle where is under pressure.

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Old 31st July 2020, 09:10 AM   #2
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"The negative pressure".

Reminds me of Rush's "Tom Sawyer". In the middle of the song Geddy just belts out "The River!!".
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Old 31st July 2020, 10:37 AM   #3
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Because the void above the liquid is under at least a partial vacuum.

When the seal at the bottom of the bottle is broken (carefully obscured by the placement of text), the liquid is pulled up and the bottle is pulled down by that vacuum and the pressure outside the bottle.

Simply two masses (liquid and bottle) moving in opposite directions to conserve momentum from their original stationary position.
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Old 31st July 2020, 06:03 PM   #4
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A law of energy/momentum- For every action there is an equal and opposite reaction. Water exiting = bottle raising. Like the gasses exiting the back of a rocket, the rocket goes forward.
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Old 1st August 2020, 04:18 AM   #5
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Originally Posted by GodMark2 View Post
Because the void above the liquid is under at least a partial vacuum.

When the seal at the bottom of the bottle is broken (carefully obscured by the placement of text), the liquid is pulled up and the bottle is pulled down by that vacuum and the pressure outside the bottle.

Simply two masses (liquid and bottle) moving in opposite directions to conserve momentum from their original stationary position.
Maybe, but I guess thatís not the whole truth or else itís explained completely differently somehow.

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Old 1st August 2020, 04:20 AM   #6
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Originally Posted by casebro View Post
A law of energy/momentum- For every action there is an equal and opposite reaction. Water exiting = bottle raising. Like the gasses exiting the back of a rocket, the rocket goes forward.
"Water exiting = bottle raising"

The bottle protrudes upwards even before the water protrudes out of the bottle?

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Old 1st August 2020, 06:21 AM   #7
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Originally Posted by Pixie of key View Post
"Water exiting = bottle raising"

The bottle protrudes upwards even before the water protrudes out of the bottle?

🤔
What is the reaction mass of the air? Did you know that 40% of the recoil form a rifle is from the powde rgasses exiting the barrel?
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Old 1st August 2020, 06:47 AM   #8
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How you're supposed to deduce anything from that I don't know. No description of what was actually done (what triggers the event?), and a very jerky video, as well, as already noted, the text hides what is happening.

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Old 1st August 2020, 07:27 AM   #9
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Originally Posted by casebro View Post
What is the reaction mass of the air? Did you know that 40% of the recoil form a rifle is from the powde rgasses exiting the barrel?
No, did not knew that.

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Old 1st August 2020, 07:32 AM   #10
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Originally Posted by zooterkin View Post
How you're supposed to deduce anything from that I don't know. No description of what was actually done (what triggers the event?), and a very jerky video, as well, as already noted, the text hides what is happening.

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This is originel video

Under pressure inside the glass bottle. Air pushes inside the bottle, the bottle pushes first down and only then up?!?

https://youtu.be/UH3PfKZnnMo

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Old 1st August 2020, 07:51 AM   #11
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Originally Posted by Pixie of key View Post
This is originel video

Under pressure inside the glass bottle. Air pushes inside the bottle, the bottle pushes first down and only then up?!?

https://youtu.be/UH3PfKZnnMo

��
1. Frankly I do not see any downward motion in the second video.
2. I think the apparent downward motion in the first video is just due to the bottle slipping down between the chairs when it is rocked by the motion of the stopper being first drawn into the bottle. Not an action/reaction thing but only a bottle insecurely propped on wobbly chairs being rocked and then slipping down due to gravity.

Why are the chairs thrown upward and to the sides once the bottle starts to go up? Seems odd unless there is a lot of friction between the bottle and the towels/chairs. In any case the setup leaves a lot to be desired and not much can be concluded from it.

Last edited by Giordano; 1st August 2020 at 07:54 AM.
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Old 1st August 2020, 06:37 PM   #12
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Originally Posted by Giordano View Post
1. Frankly I do not see any downward motion in the second video.
2. I think the apparent downward motion in the first video is just due to the bottle slipping down between the chairs when it is rocked by the motion of the stopper being first drawn into the bottle. Not an action/reaction thing but only a bottle insecurely propped on wobbly chairs being rocked and then slipping down due to gravity.

Why are the chairs thrown upward and to the sides once the bottle starts to go up? Seems odd unless there is a lot of friction between the bottle and the towels/chairs. In any case the setup leaves a lot to be desired and not much can be concluded from it.

It looks obvious to me that what GodMark2 said is correct. The area above the liquid initially decreases and air comes in to fill some of the bottle below the liquid. If the stopper could have been instantaneously replaced with an initially empty balloon, that balloon would have been sucked in, and would have stayed that way.
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Old 1st August 2020, 11:40 PM   #13
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Originally Posted by Giordano View Post
1. Frankly I do not see any downward motion in the second video.
2. I think the apparent downward motion in the first video is just due to the bottle slipping down between the chairs when it is rocked by the motion of the stopper being first drawn into the bottle. Not an action/reaction thing but only a bottle insecurely propped on wobbly chairs being rocked and then slipping down due to gravity.

Why are the chairs thrown upward and to the sides once the bottle starts to go up? Seems odd unless there is a lot of friction between the bottle and the towels/chairs. In any case the setup leaves a lot to be desired and not much can be concluded from it.
The motion is there, but the downward section only occupies about three or four frames of the video, and is only a few tens of pixels in total.

When the stopper fails, air+liquid rushes into the vessel. From this, the bottle is forced down by the air pressure above and the vacuum inside. Previously, this was balanced by the air pressure at the stopper, but when that failed, there was no more net pressure where the stopper used to be.

The chairs are forced apart when the bottle moves down. This causes the bottle to move down less than is would had it been impeded as energy is put into moving the chairs. It also appears that the wicker legs of the chairs flex a bit, acting like a spring.

Then the partial vacuum inside fully equalizes. When this happens, the liquid still has momentum, and begins to compress the remaining gas and/or to impact the top of the bottle. This compression/impact then causes the bottle to accelerate up. Without the chairs impeding the downward acceleration of the bottle, this acceleration would exactly counter the original downward acceleration. But, as the chairs stole some of that downward acceleration, the upward acceleration is now greater than the portion of acceleration that was put into the bottle, causing a net upward acceleration. The spring action of the wicker legs adds to this upward acceleration.

Sorry, Pixie of key. You may wish for more complication, but wishing does not make it so.
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