I was rummaging in a storage closet, & found some old-ish bottles & cans of soda that had fallen down behind some other stuff. Never been opened. I'm looking at 3 plastic bottles & 2 cans of diet Coke, dated June'07; & a 6 pack of Sprite in plastic bottles, dated June'08. All of them are visibly concaved, anywhere from about 10-20% percent. You know I'm not talking about the normal shape of the bottles. These all have the kind of concave warpage that you'd see if you opened a bottle of water, drank some, reclosed it & left it in a cold place. You know, the cheeks of the bottle & cans are sucked in.
The bottles & cans have all been indoors all along. (If they'd been in the garage, I wouldn't be surprised at all sorts of weird heat warpage.) I'm actually quite impressed that the cans didn't fail & leak. I'm not sure whether I want to undertake the science experiment of opening any of them. I certainly wouldn't dream of ingesting any of the contents!
So, does anybody have any ideas about what is happening inside those containers?? I'm really thinking that 2-3 years past their "use by" dates shouldn't produce that much weirdness in big-production soda! I always figured I could wash down my post-apacalyptic Twinkie with a refreshing Coke.
I tried googling, & all I came up with is a whole lot of articles about why bottles & cans are designed with indentations & a concave bottom -- not helpful.
Is it possible that something happened after the bottles & cans (uh just clap your hands) fell that was caused by the sudden surge of pressure and gradual release? I guess it would be easy enough to test if you gave a sample a good shake then enough time to see if the shape was affected. Ordinarily you just wait for the pressure to subside and then you're out of danger, but I've never just let one sit for a couple of years after dropping it on the floor.
Other than that, I'd guess that there must have at some point been a wide enough change in temperature (power outage?) to make them shrink inward.
Ok, what is under the floor? Do you have a basement or are you on a slab, or was this on a 2nd floor?
Considering that you're not in a climate that is likely to freeze, I'm still voting for temperature flux, such as a very hot afternoon and then the AC worked over time and since they were on the floor and maybe there was a strong draft pulling under the door they were cooled relatively quickly...
My second vote is aliens, though you're in the wrong part of the state :P
Slab, centrally located. No major outages -- temperature fluctuation at most 15F degrees.
Regarding aliens, really anyplace in the state is all fair game, so I find that to be a perfectly plausible explanation.
OK, I have placed a plastic bottle of Diet Coke, same size, dated Jan'10, outside in full sun. Assume starting temperature is room temp where the bottle had been stored -- 78.6F according to a digital thermometer. Outside, the thermometer nearby in the shade reads 87F for air temperature, & the ground isn't particularly hot, but being in the sun should warm it up. I've accurately marked the "waist size" of the bottle with a narrow strip of paper, & tacked that down with a small piece of yellow stickie. I'll give it a couple of hours in the sun while I try to figure out how to get a temperature estimate in the bottle without opening the bottle. (Hmm.)
Then I have 3 choices: 1) bring it back to indooor room temp; 2) put it in the wine closet (57F, IIRC); 3) toss it in the fridge. Any votes? I'm only willing to sacrifice so many bottles of soda for a science experiment.
My hypothesis is that: the waist of the bottle may expand some while it's hot, but then go back to it's starting size, with no dicsernable warpage. For the second phase of the experiment, I'll have to get back to you in 3 years. :-)
As the sun is starting to set, the bottle is warm to the touch, zero indication of expansion at the "waist", estimating bottle temperature to be 94F -- wrapped the bottle in a towel with a digital thermometer peeking out, & let it stabilize. Just for giggles, lets give it a good shake on the way into the refrigerator.
When you found one of the original bottles, was the liquid in contact with the lid? In other words, was the bottle at least somewhat upright? I'm wondering if the liquid had a chance to escape, even minimally, through the lid over the course of its time in the closet.
I approve of your experiment, but I'd try to place the bottle in a simlilar position to how you found the warped subject.