Air pressure bottle experiment

[harrymetu]

​At first, the total air pressure and water pressure inside the bottle at the intial depth of the red straw is greater than the air pressure from outside, not great enough for water to flow out through the top of the straw, but enough to prevent air from outside from moving into the bottle( water). Same with the blue straw. As the red straw is pulled upwards, the total air pressure and water pressure in the bottle through the straw decrease because the depth decrease, eventually reaching a depth in which air pressure from outside is greater than it. Thus air moves into the bottle(water) through the straw, and as air bubbles ascend to the top space in the bottle with air, the air pressure inside the bottle increases. Then total air pressure and water pressure at the depth of the blue straw then exceeds the pressure outside the it and pushes water out from the bottle through it!
Pretty cool!!

[manoocgegr]

Oh God. Took my an hour to understand this. Solution is to think simple. When the red straw is below blue straw, system is at equilibrium. Air cant go through red one because of the head from water surface to the bottom end of the red straw. Also air cant get in because of the head from blue straw ti the bottom end of the red straw. When the red straw is pulled up, notice the guy PINCHED the straw. This causes a drop in inside air pressure (like a syringe effect) so when he releases the red straw the air flow inside and it makes a condition like the bottle cap is open so water flows. Its all about that pinching

[KMVclassic]

At the start there is vacuum in the bottle above the water. When the straw is lifted, the vacuum is strong enough to break the water barrier and the bottle sucks in air from outside. The vacuum inside the bottle is now filling with air, the Atmospheric pressure in the bottle pushes the water out.

[cutiepommy]

Thanks bro I have been searching for this kind of project❤

[dsp]

So simple and elegant. Both the experiment and the video

[asria]

(I'll state what i understand from my previous studies)

inside the bottle we have water vapor pressure because its a system and the water inside has an empty space above it so there will be some sort of vapor pressure even though it is room temperature (we don't necessarily need to reach boiling point for that, liquids have different vapor pressures in equilibrium states over a wide range of temperatures).

This vapor pressure is not equal to the atmospheric pressure, yet not way too small for the atmospheric pressure to crash it.

What i think happened is that at first, when the put the straw, he pinched it so that no more air get into the straw, and he dipped it until it reached it's initial position.

The pressure in the straw is not equal to the atmospheric pressure either, according to the law of conservation of mass in fluid dynamics (venturi effect), since the area decreased(its narrow), the pressure increases as for p=a/m where m and p are inversely proportional.

And since they did use an object like a staw, the action of pressing it downwards (even though it seems that it has a little pressure, it will affect the system, at this point, the system is not closed because due to the blue straw, it can lose mass, but in the initial position, where no matter entered or exited the system we can treat it as if it was closed until the water exits the blue straw) dipping the straw (till this level) will increase the pressure andeventually it was equalized with the outside pressure so that it stays at equilibrium (im talking about how it reached its initial position)
so now we have the pressure inside the straw which is more than the atmospheric pressure, and its pressing on the water surface, the pinching was to keep the forces and pressure as desired and not to let any more air particles press into it to keep it at equilibrium, so when it was pressed downwards, according to Archimedes principle the water displacement will be equal to the volume of the straw, thus increasing the vapor pressure inside the system, and thus, equalizing it with the atmospheric pressure.

Now we have a state of pressure equilbrium.

And then, When the straw is lifted, the stress from inside the water particles of the high pressure is less since the water is exposed to less surface area, ( the pressure decreases) and the atmospheric pressure on the straw will be greater than the vapor pressure(when the straw was lifted it was no longer equilibrium), thus pushing it downwards creating bubbles blubblubblubblub.

Because the system before that was at equilibrium with its environment, no water leaked from the blue straw. But as the system had undergone stress according to Le Chatalier's principle, it will have a new vapor pressure equilibrium.
This can be achieved by changing temperature and vapor pressure for a closed system, but since this system can no longer be treated as closed, the way it "copes" with the stress is through losing the mass it lost from the blue straw, (not the red staw obviously cuz atm pressure is higher) so the only exit is the blue straw that is not faced upwards thus the pressure still affects it but the net force is in a different direction, and the pressure affecting it from the right is less of coursw. So the water will flow to a certain amount until the system equilibrium is reached again.

OH MY GOD I FEEL THAT ALL MY PHYSICAL CHEMISTRY GRADE 10 STUDIES HAVE LED TO THIS MOMENT

[UselessGuy]

Its going to be a good idea for a water dispenser but its too small

[Casper-fofl]

The straw is pulled up and the air is strong enough to put more air in the bottle allowing it to let water out as it can draw more air in to replace the water volume with air

[what-unyq]

Oh, that noise. I can't handle that.

[melissavirtue]

I'm about to make it. It'd so cool!

[Adekalo]

It's called a siphon, ok so you know its name 😉

[arthicle]

I do not agree with what people say here and i'd like to explain my pov, i may be wrong though. If anyone thinks i'm wrong i'd be delighted to hear why !

In the very beginning, at water level we have atmospheric pressure, the height of water is the same in the straw and in the bottle, because the air in the bottle and in the straw are both atmospheric pressure. The pressure at the inlet of the blue straw is greater than atomospheric pressure though, since there is a certain height of water to be added. The pressure at the outlet is atmospheric pressure but there is also surface tension which helps maintain the equilibrium with the inlet pressure, therefore there's no flow. Everything is at equilibrium. Then the guy pinches the straw, which doesn't allow the air from the environment to get in. By lifting the straw while keeping it pinched, the air stuck is expanding, therefore lowering its pressure (pV=nRT, right hand side of the equation is constant but on the left side we raise V therefore to keep it constant p must be lowered). Now, still while lifting the straw pinching it, the air in the straw excerts a lower pressure on the water than the air in the bottle. Therefore, water is sucked through the red straw, lowering the air bottle pressure since it now expands because of the water flow in the red straw, until equilibrium is reached (pressure at "bottle level" is the same everywhere, so p_bottle = p_redStraw + pressure due to extra height of water in the red straw, with respect to the water level).
Now we have reached equilibrium and the "highest height of water" has been raised. This is important since as mentionned before, for the blue straw, the inlet pressure depends on that highest height of water. Now when he finally stops pinching the straw, atmospheric pressure is back in the red straw, but this time we have built that extra height of water, which results in a greater water pressure at the inlet of blue straw. The inlet pressure being greater than the outlet pressure + surface tension, flow begins. Then due to inertia it keeps for a while

[shawnmolnar]

It's hydronic pressure resisting atmospheric pressure when the straw is lower.

[vladmatsala]

If the red straw is lifted the amount of water over the blue straw is bigger. Now it's easier for water to flow(fall) sucking air through the thinner layer. Brilliant experiment😊🎉

[ganeshs]

I hate how my mind can understand this in high school and not now

[wildergomez]

I need this for my plant for when I travel for work. thank you for sharing

[vivekg]

Dear youtuber pleasd share the complete process, so that we may replicate it and see for ourselves. Regards

[myquotes]

How to make this can you please explain😢

[MichaelSkinner-ej]

This is the solution! I just have to figure out how to scale it up and how to implement it

[goatgaming]

bro fr just made a water bottle bong lmao