Question

we pour hot water over the tightly secured lid to open it. give reason​

Answer 1

Explanation:

on pouring hot water.. the lid expands to become loose

and thus it helps to open it easily.....

Answer 2

Answer:

Simple thermal expansion of the metal by the application of a splash of hot (I tend to use boiling from the kettle) loosens the lid. Just wipe off the water with a towel, get a good grip, et voilá, it unscrews!

Simple thermal expansion of the metal by the application of a splash of hot (I tend to use boiling from the kettle) loosens the lid. Just wipe off the water with a towel, get a good grip, et voilá, it unscrews!Another ‘hack’ I invented myself is useful if you have no hot water handy. Just grab the top of the jar and make the unscrewing action for a few seconds so that the friction of your grip sliding along the edge heats it up. There is sometimes just enough expansion of the metal from doing that to loosen the lid.

Simple thermal expansion of the metal by the application of a splash of hot (I tend to use boiling from the kettle) loosens the lid. Just wipe off the water with a towel, get a good grip, et voilá, it unscrews!Another ‘hack’ I invented myself is useful if you have no hot water handy. Just grab the top of the jar and make the unscrewing action for a few seconds so that the friction of your grip sliding along the edge heats it up. There is sometimes just enough expansion of the metal from doing that to loosen the lid.Another possible reason for difficulty is that, having been filled while hot, when cooled the air at the top has contracted, producing a partial vacuum that is ‘sucking’ the lid on tight. The hot water will also resolve that by expanding that air and undoing the vacuum effect.

Simple thermal expansion of the metal by the application of a splash of hot (I tend to use boiling from the kettle) loosens the lid. Just wipe off the water with a towel, get a good grip, et voilá, it unscrews!Another ‘hack’ I invented myself is useful if you have no hot water handy. Just grab the top of the jar and make the unscrewing action for a few seconds so that the friction of your grip sliding along the edge heats it up. There is sometimes just enough expansion of the metal from doing that to loosen the lid.Another possible reason for difficulty is that, having been filled while hot, when cooled the air at the top has contracted, producing a partial vacuum that is ‘sucking’ the lid on tight. The hot water will also resolve that by expanding that air and undoing the vacuum effect.I resort to this only after I have tried inverting the jar in the hope that the liquid inside will lubricate the lid from the inside, dissolving crystals of salt

or sugar for example. Just don’t unscrew it while it’s still upside-down! ;)

Explanation:

Hope this helps you mate