why carbonated drinks bottles collapse when you add water and shake

[@OlliWilkman]

If the bottle contains air at room temperature, and you add cold tap water and shake, the air inside cools rapidly and shrinks, lowering the pressure. I've done the reverse when rinsing an empty beer keg with hot water; the pressure relief valve popped as soon as I closed the lid and shook it.

[@DarkJMKnight]

Yeah, I was thinking it was more about temperature than solubility, having done this myself often in bottles that had only ever contained water.

[@RogueShadowTCN]

I thought the same thing.

[@ProasekSR]

Always nice to see theories get tested, even for quite mundane events!

[@sharpfang]

This works without CO2. You just need water considerably cooler than air - room temperature air and ice water is quite enough. Shaking simply speeds up the heat exchange between the water and the air, the air cooling reduces in volume. Works in the opposite direction too - with hot water you'll get high pressure and a spray of hot droplets as you open the cap, so use caution.

[@EebstertheGreat]

This might be the first time I've seen a bottle of pop in that shape.

[@pittiebaby]

The beginning almost gave me a heart attack 😂

[@Meikulish]

These are the kinds of things I wish I'd thought to wonder about! Immediately realized I've seen that before, but I'm not sure I ever would have noticed how weird it is.

[@Uncreeperble]

Omg there are not many comments, I really love your science passion Steve!!!!

[@SP-001-X-U.S.A]

Dr Pepper do be hitting hard

[@LieseFury]

whoa, you still have the 90s dr pepper design? we're stuck with the 2000s era ugly swooshy blobby logo.

[@Jademalo]

This is really interesting, because it seems similar to something else I've experienced. I've got a water bottle with one of those locking spring loaded caps. Whenever I wash it out with warm water and fairy liquid, as soon as I open the cap it sprays soapy water *everywhere*. I've never been able to make sense of it since the pressure somehow *increased*, but I wonder if the soap is doing basically the opposite and releasing dissolved gasses in the tap water?

[@cemafor1006]

I think in that case the air is actually warning up and expanding since it likely started at room temperature before closing the lid

[@Meikulish]

I think we need a control test without the soap. Just warm water and shaking. No bubbles to show the air escaping, though so might not be obvious whether there's a difference.

[@Jademalo]

@@Meikulish well that's extremely interesting - the pressure didn't build. It's quite obvious with the cap popping off.

[@Solo-Anarchist]

How is there CO2 left in the bottle after you finish drinking it? This makes no sense.