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/sci/ - Science & Math

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2640409 No.2640409 [Reply] [Original]

when you have a bottle with holes in it and water filled above the holes, the water only leaks out if the cap is on. why? like in terms of pressure...?

>> No.2640415

I always thought water leaked out regardless if the cap is on or not.

>> No.2640421

Because the holes are in the cap, and if you take the cap off then it does not qualify as leaking, it is simply fulfilling the regular function of a water bottle.

Did I get it right?

>> No.2640427

the holes are in the bottle. not a riddle lol

>> No.2640430

When the cap is on it creates a barrier between the water and air, preventing the air on top from exerting pressure. The air next to the holes can still exert pressure on the water and keep it contained.

>> No.2640435

>>2640430
hmmmmm OK

>> No.2640459

Is this true? I just looked it up and it says it is. But why when I punch a hole in a water bottle will it leak? If I just right now poked a hole in one, unopened, with a pencil would it leak? How calmly must the hole be punched?

>> No.2640488

>>2640459
yeah i dont get it. seems like it would. time for OP's pic?

>> No.2640526

you now know every 2 liter and 20 ounce bottle is made with tiny holes near the cap which never leak liquid, but allows gas to escape

>> No.2640587

I think he means that if you punch a small hole in a water bottle, the viscosity (is that how you spell it?) of the water will be just great enough to stop the water from coming out the hole when you remove the atmospheric pressure from the top (cap is on), but not the sides. This resistive force is not strong enough, however, to keep the water in the bottle with the atmospheric force still present (cap is off)

>> No.2640632

>>2640409
>>2640587

you have it backwards, water only leaks out if the cap is on because then, the bottle is a closed system and the pressure is equalized enough that the surface tension can hold the water in the bottle unlike when the cap is off and the bottle is an open system with atmospheric pressure pushing on the top of the water and forcing it down enough to break the surface tension at the hole and leak out

>> No.2640642

>>2640632

why did I say it backwards too

To reiterate water leaks when the cap is off, but stays in equilibrium when the cap is on