Asked in Chemistry
Chemistry

Why does water bubble up on a penny when you add drops of water to it?

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Wiki User
09/21/2010

The water bubbles up because of cohesion.

Cohesion: the force of attraction that holds together a substance's molecules; cohesion is strongest in solids, weaker in liquids, and weakest in gases.

The water doesn't spread out evenly all over the penny because the H2O molecules are so strongly attracted to each other (opposites attract, so yeah, hydrogen is pos. and oxygen is neg, so one H2O molecule is attracted to another one, either through the hydrogen molecules or the oxygen molecules) that it forms a bead because they're all grouping up together.