Comment on My ravioli bowl won't unstick. Took about an hour of prying, and still I couldn't unstick the plate.
XeroxCool@lemmy.world 4 days agoHow do you figure suction is very limited? You’ve never tried to pull a suction cup straight off, have you? I’m not talking about when suction cups have bad sealing surfaces and slowly leak to the point of popping off or peeling suction cups off from a corner, I’m talking applying it to a good surface and then yanking it.
A shoddy 4.5" suction cup from Harbor Freight is rated at 80lbs carrying capacity for glass, which happens to likely be the same material as the dish (corelle), judging form the thinness. The bowl is probably plastic and had weight on it while these were hot and wet after washing. Please, let me know if you can lift an 80lb dumbell from the end with a single hand with ease.
FreeBeard@slrpnk.net 3 days ago
The difference between ambient pressure and inner pressure is always smaller than ambient pressure. Delta p is therefore limited. The force comes from Delta p times contact area which is constant.
I sadly don’t know your units of mass but as I said a perfect vacuum over an area such as the Bowl is as strong as a muscle. The Ravioli will in no world produce a strong vacuum so muscle will win in most cases.
XeroxCool@lemmy.world 3 days ago
Here, I’ll do metric for you on your theory of muscle being equivalent perfect vacuum. I have some similar corelle dishes. The flat measures 10cm across. That’s 78. 5cm^2 area. Assuming OP lives at sea level, 1atm is 1.033kg/cm^2 which puts the total force at over 81kg. This bowl offers no horizontal surfaces to hook fingers under to utilize geometric advantages and is instead entirely dependent on friciton. If your fingertips can squeeze sideways with enough force to pull a smooth, tapered 81kg object without glue, there’s a gold bar in a Dubai mall with your name on it.
4 inches diameter, 12.6in^2, 180lbs for the Americans.
At some point between 0 and 81kg of force, I’d start worrying about breaking the plate with such little support around the rim. And, as for the impossibility of a perfect vacuum, I’d be easily convinced the bowl could have more than half of the maximum possible pressure differential. A large portion of the interior volume is probably ravioli, minimizing the gas volume. Ravioli are full of water, which means the remainder of gaseous volume in the bowl was probably mostly steam, pushing out the standard air. Steam has an insane compression ratio as it cools and condenses back into water, at about 1700:1. Go watch the video of a tank car imploding from steam condensation.
I cover my bowls the same way. I always cock the plate to the side for this exact reason. My 1L (4 cup) pyrex bowls with silicone lids can cave 1" if they’re allowed to cool for a minute. Steam easily vents from the rim as it’s produced but once it starts cooling, the weight of the lid or plate is plenty to get the initial seal