Tapping jars

Today I watched my aunt try to open a jar of pickles and she couldn't do it. Then another aunt came up, turned the unopened jar on a side, hit the bottom a few times, and easily opened it. What does hitting the bottom of a jar do to make it easier to...

open??

Jars ae sealed tightly with presure tapping it at the bottom sends presure to the top lid which releases it slightly due to the force of pressure caused in the jar against the metal lid. Do I make sense?

releases button or seal.

Dear lifeoftheparty20,
yes, tapping the lid on the jars will loosen slightly to open easier. However, a safer approach would be to take a spoon and carefully place under the lip of the lid and gently pry braking the seal. That way your sure not to have a mess if you tap too hard.
Sue