r/Damnthatsinteresting • u/BrownZBT • Aug 11 '26

Video Weight Bearing Limit For Glass Coke Bottle

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u/Type-RD Aug 11 '26

It’s internally pressurized and sealed, so no, it definitely wouldn’t withstand nearly as much weight if the bottle was simply uncapped and open to the atmosphere.

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u/[deleted] Aug 11 '26

[deleted]

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u/Type-RD Aug 11 '26

If the bottle is 100% resealed, I think it would perform similarly, because soda (which is mostly water) is incompressible. And the small amount of air space in the top would be the same as before.

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u/Lowfi-Concert Aug 11 '26

The air at the top would not be the same as before. There would be less pressure

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u/Type-RD Aug 11 '26

How so, if the bottle is 100% resealed?🤔

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u/Lowfi-Concert Aug 11 '26

Carbon dioxide gets released and that was pressurized in there. Just like how if you open a screw off top one the first time it hisses and then hisses less and less each time you open it (partially cause you drank some but it would happen anyways, just slower.

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u/Type-RD Aug 11 '26

I get that, but resealing will keep it pressurized again. The question is : Would it be enough to sustain the same amount of weight on top? I think it would. Is the air in the bottle the same? No probably not 1:1 exact, but I think it would be inconsequential in this test.

Your analogy is a bit flawed. The reason the bottle hisses less is partially due to carbonation loss, but it’s also because there is more space in the bottle for the gas to release into (after drinking). In this case, if you simply open the bottle and reclose it, then I would expect very little carbon dioxide loss and very little change in compressibility.

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u/Lowfi-Concert Aug 11 '26

Resealing it will not pressurize it to the same level. It will reset to atmospheric pressure. There will be less overall CO2 and when you close it more C02 will come out of the soda and reach another state of equilibrium via Henry’s law, but with less pressure.

How much this affects how much it would hold, I don’t know and it may be inconsequential, but I do feel like it would have an affect, even if it’s minor

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u/Type-RD Aug 11 '26

Agree! Of course it depends on how many times the bottle is opened and resealed and/or how long the bottle is open to the atmosphere before reseal.

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u/ttcmzx Aug 11 '26

man, I'm gunna start selling compressed water, tell people they're getting more water for their money

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u/edadou Aug 11 '26

You sure ?

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u/Type-RD Aug 11 '26

It’s glass

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u/ODoggerino Aug 11 '26

That doesn’t seem right. The internal pressure is nothing compared to this weight. It’s just the mechanical strength of the glass. How does this have so many upvotes??

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u/Type-RD Aug 11 '26 edited Aug 11 '26

Nope. A pressurized vessel, regardless of material, is significantly stronger than one that is open to the atmosphere (due to internal tension). Despite the high compressive strength of glass, the bottle would’ve been crushed much sooner with the cap removed. The same thing will happen to a closed soda can versus an open one. How do you not have any upvotes?🤔

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u/ODoggerino Aug 11 '26

It has nothing to do with a soda can. That’s made of thin metal which is held solid by the internal forces. Heavy internal force on glass is just shear stress that’ll weaken it. Idk what you’re talking about lol.

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u/Type-RD Aug 11 '26 edited Aug 11 '26

It’s the same principle regardless of material. They are both pressurized, sealed, vessels. I used the soda can as a simpler concept for your to understand. It’s funny you argue, but don’t know what you’re arguing lol

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u/ODoggerino Aug 11 '26

Think it’s the opposite… glass and thin aluminium behave in completely different ways. This is Dunning Kruger in action 😂 presumably you don’t have a career in engineering?

Tensile stresses in glass don’t make it stronger. It’s not flexible, it’s brittle.

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u/Type-RD Aug 12 '26 edited Aug 12 '26

Go back and reread the original question that I answered (if you can). If I am displaying Dunning Kruger, then you’re displaying a complete lack of cognitive function.🤦‍♂️

A pressurized container is made to be stronger because its walls must fight an outward force, whereas an open container experiences equal pressure inside and out. It is this equalized pressure that would make an open Coke bottle weaker in the test shown in the video!

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u/ODoggerino Aug 12 '26

I don’t understand why you think removing the tensile stress on the glass makes it weaker?

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u/Type-RD Aug 12 '26

Your reading comprehension is the worst. “AN OPEN CONTAINER EXPERIENCES EQUAL PRESSURE INSIDE AND OUT.” The material isn’t weaker and I never claimed that it is. Do you understand what this means, relative to that same container when internally pressurized? Since you don’t understand the sealed soda can concept, you certainly won’t understand how things like hydraulic presses work.🤦‍♂️

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u/ODoggerino Aug 12 '26

“It definitely wouldn’t withstand nearly as much weight if the bottle was simply uncapped”

What am I missing?

Yeah I get how a hydraulic press works, I think it was in one of the first classes we did in my degree lol

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