Collapsible can

 
We have been having some very warm weather up here in the north east recently which makes a change from the cold we had to endure over the very long winter but just look at this can that I foolishly left near the open door of the workshop and therefore in the bright sun. The can looks like I had crushed it on purpose ready to take to the recycling center with the rest of the trash but in fact that is not the case, it did this by itself. I am not sure why this happens but atmosphric pressure has collapsed the can which actually now has a split in it. I know it always says to open cans of paint stripper carefully to allow the pressure to equalize but I would love to know the scientific reason, if anyone can shed some light on this phenomenon then I would love to hear it.

Comments

[Matt]

Well, your story doesn't quite add up to what I would expect to happen, but maybe theres a detail or two missing.

Either way, Hot air is less dense than cold air. Put the cap on a container while it's warm, and when it cools, the air inside will want to take up a smaller volume, lowering the pressure, until sometimes, it collapses the container.