|The fruits of our labors.|
I got the top off of a jar of pickled artichoke hearts, and let me assure you that it was no mean feat.
The jar, you see, had been in the refrigerator for some time, and the lid was on quite tightly. Being experienced with this sort of challenge, I first called my dad over to help, then I put some water on to boil. When Dad's good ol' meathooks didn't work (that would be "hands" to any plebs out there), we put the jar in the pot and waited.
Just put the jar in the increasingly hot water and let physics work its magic. With smaller jars, running the top under hot water suffices (special heat and all that; the metal lid gets hot faster than the glass and gets slightly bigger and it opens really nicely), but in this case, we made use of the gas laws. We all remember the gas laws and such, right? PV=nRT? In this case, the most important bits were P1T1=P2T2. The air in the top (there was not much, but enough) pushes on the lid and gives enough of a helping hand for Mom and me to enjoy a delicious treat.
Hey, look, a practical application of science! Who'd have expected it?
(Bonus advice: don't put the lid back on the jar and stick it in the fridge until after it's cooled off, okay? You'll thank me later.)