why does a coaster sometimes stick to the bottom of a glass

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why does a coaster sometimes stick to the bottom of a glass

In: Chemistry

3 Answers

Anonymous 0 Comments

Suction.

The condensation or spilled liquid gets underneath and when the glass sits down, the weight pushes the glass down against the coaster. Air moves out of the way fast enough but liquids don’t always and if the liquid fills in all “the gaps”, it creates a vacuum. The air pressure surrounding the coaster/liquid/glass becomes stronger than the weight of the coaster… so it holds.

Anonymous 0 Comments

Condensation from the glass makes the paper coaster stick to it. Put some salt on the coaster first and it won’t stick

Anonymous 0 Comments

Pro-tip: if you put a little bit of table salt on the napkin/coaster, the glass won’t stick.

That’s all I have to contribute here.