Physics behind flow of water from a bottle

[rambharath94]

Hello Guys;

If u turn a water bottle(full of water) upside down and bring it down towards water present in a bigger vessel than the bottle's mouth. Then water from the bottle will stop flowing at the moment the bottle's opening (mouth) gets immersed in the water present in the vessel why ?

 

[siddharth5129]

this would happen at the moment the vacuum created in the wake of the water flow becomes strong enough to support the weight of the water in the bottle. it won't necessarily be at the moment the mouth of the bottle touches the larger fluid surface in the bigger vessel.

 

[256bits]

Good answer, but...

To be physically correct, if we take the surface of the larger body of water as a datum level, it would be the atmospheric pressure on the surface of the larger body of water supporting the pressure from the height of water in the bottle above the surface of the water.

It acts the same way as a barometer.

With lower atmospheric pressure, more of the water would flow out of the bottle.
In fact, if the atmospheric pressure could be zero ( a vacuum ), all the water would flow out of the bottle.

 

[A.T.]

If u turn a water bottle(full of water) upside down and bring it down towards water present in a bigger vessel than the bottle's mouth. Then water from the bottle will stop flowing at the moment the bottle's opening (mouth) gets immersed in the water present in the vessel why ?

What replaces the water in the bottle, when the water does flow? Is this still possible when the mouth is submerged?

 

[Nathanael]

What replaces the water in the bottle, when the water does flow? Is this still possible when the mouth is submerged?

Couldn't it still "fill up" with vaccum? I would still consider that to be water flow.

 

[A.T.]

Couldn't it still "fill up" with vaccum?

Right, but leads to the pressure imbalance mentioned by others already. I was pointing out what is different between the two cases.

 

[rambharath94]

this would happen at the moment the vacuum created in the wake of the water flow becomes strong enough to support the weight of the water in the bottle. it won't necessarily be at the moment the mouth of the bottle touches the larger fluid surface in the bigger vessel.

how exactly is the vacuum created inside the bottle isn't it like the air flows inside the bottle at the same time the water flows out of it , this can be seen in water dispensers when u open the tap , water bubbles raise inside the water can?

 

[rambharath94]

What replaces the water in the bottle, when the water does flow? Is this still possible when the mouth is submerged?

I think air is the thing that replaces water , but i'am not sure how this will work in vacuum ? If air is the thing that is replacing , then water will not stop to flow at the moment the mouth gets submerged in case of vaccum.

 

[rambharath94]

Good answer, but...

To be physically correct, if we take the surface of the larger body of water as a datum level, it would be the atmospheric pressure on the surface of the larger body of water supporting the pressure from the height of water in the bottle above the surface of the water.

It acts the same way as a barometer.

With lower atmospheric pressure, more of the water would flow out of the bottle.
In fact, if the atmospheric pressure could be zero ( a vacuum ), all the water would flow out of the bottle.

So u are saying that it does not depend on the criteria of submergence?

 

[Khashishi]

Under normal situations, in order to empty a bottle of water, you have to fill it with air. If you turn a bottle upside down, water leaks out the opening, and air leaks in. But if you put the top of the bottle underwater, you can't get air to leak in anymore, so the bottle can't empty.

(but if your bottle is over about 10m tall, you might see the water at the top of the inverted bottle start to boil and a layer of water vapor form at the top)

 

[rambharath94]

Under normal situations, in order to empty a bottle of water, you have to fill it with air. If you turn a bottle upside down, water leaks out the opening, and air leaks in. But if you put the top of the bottle underwater, you can't get air to leak in anymore, so the bottle can't empty.

(but if your bottle is over about 10m tall, you might see the water at the top of the inverted bottle start to boil and a layer of water vapor form at the top)

What in case of vacuum that is the main concept i don't understand?

 

[Khashishi]

You need to be more clear.

 

[rambharath94]

You need to be more clear.

I need to understand how the water flow will be in case of vacuum , will it terminate at the moment the bottles opening is submerged in the bigger water surface(this is the case where air is present) or not ?

 

[siddharth5129]

Where is this vacuum present? If it's present throughout your system, then the water flow won't terminate until all the water from the bottle has flown into the bigger container (Because there's no air pressure to counter the weight of the water in the bottle ) If you're talking about vacuum present above the column of water in the bottle, then it would terminate as soon as the weight of the column of water is exactly balanced by the atmospheric pressure on the rest of the water surface (the water in the larger container I mean ). It doesn't depend on when the bottle opening comes in contact with the larger surface (if it doesn't come in contact at all, then all your water would flow out of course )