Does a Water Molecule Have a Lifespan?

Water molecules shift hydrogen atoms constantly, so technically a molecule's lifespan is very short. CREDIT: NASA. View full size image

Stagnant water may appear motionless, but a closer look reveals a swingers party at the atomic level. Take oxygen, one of the universe's commonest elements and a popular molecular partner, breaking it down on the dance floor with two giggling hydrogen atoms on either arm.

The common depiction of H2O as a monogamous trio of dancers is a prude fantasy. In reality, hydrogen atoms are constantly shuffling from one molecule to the next, pairing with a particular oxygen for only a millisecond. This might be described as one trio's "lifespan." But the swapping doesn't stop there. Two oxygen atoms can actually share a hydrogen between them. "Hydrogen bonding " describes this special arrangement in which a single hydrogen is considered attached to two discrete water molecules.

Many forms of hydrogen bonds are found in liquid H2O, much like different moves on a filled dance floor. But it's certain that you won't find any three partners paired for long.

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