this morning my mom and i couldnt open a PB jar and later my sister opened it why? temperature change?

Question

could it be because of the pressure change from the temperature in our house being colder in the morning, so less force was being exerted on the lid, and later it was easier because it was warmer and there was more force on the lid?

i wanna know if my sister is stronger than us! we both work out just as much as she does!

thanks~

Answer 1

Yes, temperature change COULD have made the difference.

It is more likely that you lessened it up and your sister tried it when the temperature was closer to equilibrium to that of the temperature in the jar. If the temperature is higher inside of the jar then there is more pressure and that would make it harder to open. Glass is a pretty good insulator so you can safely say that you are just as strong as your sister, until you get some other proof.

One common trick to opening up stuck jars is to run the lid under warm water. The heat will make it expand and it might expand at a different rate then the container, I know a metal lid will expand faster than a glass container; plastic is a different subject though it depends on the type and thicknesses involved.

Boyle’s law on gases: http://en.wikipedia.org/wiki/Boyle%27s_Law
Says that there is a DIRECT relationship between temperature and pressure; the higher one is the higher the other is. So in a cold house the warmer interior of the jar would certainly have more pressure keeping it closed. You can point your sister to that article and say; “See I am not weaker than you are.”

Answer 2

Maybe the pressure wasn't the issue but the temperature; the metal or plastic lid might shrink more than the jar when it gets cold, so it would get tighter on the jar when cold. You could try this as an experiment to see if it is the case.

Also sometimes when trying to loosen a lid some people grip the lid so tightly that they distort it untill slightly oval and make it even grip the jar even more.

Answer 3

lol they should be easyier to open when its warm, theres a trick to opening jars, jars are closed with a vacuum inside to preserve the contents, some jars with metal lids have a flexible bit on top if you push this in when you twist it lessens the vacuum also heating the lid under warm water will case the lid to expand and not the glass so the lid is less tight.

Answer 4

this could paintings -- i take advantage of it each and all the time: Get a screwdriver (flat-head) and gently positioned it below the sting of the jar lid and attempt to develop the backside fringe of the jar lid slightly. be careful -- you do no longer % to interrupt the glass. you will pay attention a sprint air get away from the jar and the lid will eliminate conveniently. additionally, a can opener for a lager can works nicely too. merely be careful to no longer easily open the lid with the pointed end of the can opener. yet comfortable tension will enable that air to flee from the backside of the lid part.

Answer 5

Pretty reasonable idea.. but usually when someone tugs on a jar, gives up and hands it to me it opens with the first twist. I'm guessing it happens because the person who tried before you kind of loosened it and when you tried to open it it didn't take much effort.

Answer 6

Some of the vacuum may have been released when your mom & you attempted to open the jar, thus making it easy for your sister to open it on her own. Just a thought. :)

Answer 7

Temperature changes are possible she maybe stronger or have had a better angle.

Answer 8

I think that your sister has been secretely working out and weight training. She is probably drinking protein shakes and quite possibly shooting steroids.

Answer 9

Sometimes it's just a better grip, but probably you got it started earlier.

Answer 10

Maybe she had a better grip then you two.