Scientists Say: Precipitation

In chemistry, this word describes a solid coming out of a liquid

When a copper wire is placed in a silver solution, a chemical reaction takes place. The silver precipitates out and sticks to the wire.

Toby Hudson/Wikimedia Commons/( CC BY-SA 3.0)

Precipitation (verb, “Pre-SIP-ih-TAY-shun”, noun, “precipitate”)

In chemistry, precipitation is the formation of a solid out of a liquid solution. A solution is a liquid where one chemical has been dissolved into another so that the chemical is spread equally through the fluid. But when there is too much of the chemical present to dissolve, some of it might remain solid and settle out. This is the precipitate. A chemical reaction also could cause a precipitate to form.

Precipitation has another use. In meteorology — the study of weather — precipitation just means water released from a cloud. It can be rain, sleet, snow or hail.

In a sentence

A new technique uses electricity to get the salt out of water, instead of relying on precipitation.

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Power Words

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dissolve  To turn a solid into a liquid and disperse it into that starting liquid. For instance, sugar or salt crystals (solids) will dissolve into water. Now the crystals are gone and the solution is a fully dispersed mix of the liquid form of the sugar or salt in water.

meteorology   (adj. meteorological) The study of weather as it pertains to future projects or an understanding of long-term trends (climate). People who work in this field are called meteorologists.

precipitation  (In chemistry) The creation of a solid from a solution. This can occur if there is too much of a chemical to dissolve completely in a solution. It also can be a sign a chemical reaction is taking place.  (In meteorology) A word used to describe water falling from the sky. It can be in any form, from rain to sleet, snow or hail.

solution   A liquid in which one chemical has been dissolved into another.

Bethany is the staff writer at Science News for Students. She has a Ph.D. in physiology and pharmacology from Wake Forest University School of Medicine.

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