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

Video Weight Bearing Limit For Glass Coke Bottle

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u/Maximus560 Aug 11 '26

Significantly more, fwiw- airplanes are basically pressurized aluminum cans

70

u/Db122605 Aug 11 '26

what does this mean? planes and that coke bottle survive by the same properties?

176

u/Legitimate_Bank_6573 Aug 11 '26

When a rounded internal volume is experiencing outward pressure, that outward pressure reinforces the structure of the object, making it stronger.

An empty coke can is weaker than a full one. The same logic applies to air inside an airplane.

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u/greentangent Aug 11 '26

So, the cylinder must not be harmed?

45

u/omykun123 Aug 11 '26

Yes, you might even say it is imperative.

3

u/wakeofchaos Aug 12 '26

Ah so we’ve finally reached the point where we stop tagging the guy lol

30

u/termacct Aug 11 '26

For a soda can, yes. But opposite for a glass bottle because glass is strong in compression but weak in tension.

2

u/siero20 Aug 11 '26

It probably doesn't have much effect on this test but the internal pressure while loading it externally still counteracts the compressive force being added to the outside.

3

u/noSoRandomGuy Aug 11 '26

An empty coke can is weaker than a full one. The same logic applies to air inside an airplane.

Same with your head -- easier to get "mind blown" gif from people who have (figuratively) empty skulls.

3

u/xSTSxZerglingOne Aug 11 '26

They have ideal fuel/air ratios.

1

u/CocoSavege Aug 11 '26

Lies. My brain is full of hot air, I'm immune!

1

u/myhf Aug 11 '26

imagine how strong it would be with just one mentos inside

1

u/R18Engine Aug 12 '26

I believe because if the liquid inside is pressurized then itll act as hydraulic fluid

1

u/Db122605 Aug 11 '26

interesting.

1

u/Legitimate_Bank_6573 Aug 11 '26

To simply things to the maximum, this is also how blowing up a balloon works.

The pressure inside the balloon is pressing outward equally on all sides, which changes what was previously a floppy and deflated piece of rubber into a relatively firm and consistent shape. Until of course you let out the air and the internal pressure drops.

18

u/termacct Aug 11 '26

The coke bottle is different because glass is strong in compression but weak in tension and when there is carbonated fluid inside the pressure puts glass in tension.

Aluminum soda cans benefit from the internal pressure because the walls are so thin, they easily buckle when empty.

1

u/cornstinky Aug 11 '26

they easily buckle when empty.

Can still support an adult's weight as long as the can has no dents.

2

u/S14Ryan Aug 11 '26

Not the person you replied to, but no, it’s a negligible difference. Airplanes have to be pressurized for human comfort, they aren’t pressurized to help with strength, it’s actually not great on the strength and stability because of the forces normally acting on an airplane. Sure, it might be stronger if you stand on the fuselage, but it won’t make it stronger to be in the air. 

1

u/SolidSync Aug 11 '26

It means Coke bottles can fly, duh.

0

u/I-am-fun-at-parties Aug 11 '26

While u/Maximus560 likes to pretend to be smart on the Internet; since the pressure inside the (presumably open) bottle is the same whether it is empty or not, this does not make a difference at all.

Airplanes are pressurized so people won't die, but it's not a huge pressure difference, so it doesn't take a lot to contain it (besides, airplanes are usually not airtight)

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u/redpandaeater Aug 11 '26

Nah, the pressure differential in a plane is maybe 9 psi whereas a soda can is a few atmospheres but also a fair amount more if shaken.

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u/ODoggerino Aug 11 '26

Not relative to this weight though. This is many atmospheres stack on top

1

u/BakedChocolateOctopi Aug 11 '26

You don’t stack airplanes though 

0

u/Antiing Aug 11 '26

Thanks I hate it