In science, precipitation is the process behind the condensation of water vapour in the atmosphere that falls down under the influence of gravity. Rain and snow are the results of these phenomena.

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What is Precipitation?

It is a chemical reaction in which you mix two solutions of two ionic substances and a solid ionic substance (a precipitate) forms.

For example, precipitation occurs when a part of the atmosphere saturates itself with water vapour and when the right temperature comes it condenses and precipitates. The two processes which make the air saturated are the cooling of air molecules and the addition of water vapour.

Chemical precipitation is the process of turning a liquid into a solid by turning the liquid into an insoluble form or supersaturating the solution. The precipitation reaction is a chemical event that occurs in an aqueous solution when two ionic bonds combine, forming an insoluble salt known as precipitates.

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Types of Precipitation

Precipitation plays a major part in the water cycle as it is the one which brings in the deposit of freshwater on the planet. It can be divided into three categories depending upon the form such as:

  • Liquid water
  • Ice
  • Liquid water freezes when comes in contact with the surface.

Examples of Precipitation

Depending on the forms we could witness precipitation in various forms:

In Liquid Form precipitation occurs in:

  • Drizzle
  • Rain

When the above comes in contact with the air mass at the subfreezing temperature it becomes

  • Freezing Rain
  • Freezing Drizzle

The frozen forms of precipitated water include:

  • Snow
  • Ice Needles
  • Hail
  • Graupel
  • Sleet

Classification of Precipitation

Precipitation of water vapour can be classified into different things and have different methods of formation and few of them are

1. Raindrop

When water droplets combine each other to form bigger water droplets and when water droplets freeze onto a crystal of ice, this process is known as coalescence. The rate of fall of small droplets is considered to be negligible, that is the reason behind the clouds not falling from the sky.

Precipitation is only possible when those will form into larger drops by coalescence with the help of turbulence in which water droplets collide, producing even larger droplets. Eventually, the droplets descend and become heavy with coalescence and resistance and finally fall as rain.

2. Snowflakes

Snow crystals form when the temperature freezes the tiny cloud droplets and because water droplets are more in number than ice crystals, the crystals can grow in size at the expense of water droplets as the water vapour causes the droplets to evaporate. These droplets fall from the atmosphere due to their mass as snowflakes.

3. Hail

Like other precipitation techniques, hail forms in the storm clouds when supercooled droplets come in contact with dust and dirt. The storm’s updraft blows the hailstones up and lifted again after the updraft dissipates.

In meteorology, any result of atmospheric water vapour condensation that comes under cloud gravity is precipitation. The main types of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel, and hail. Precipitation happens when water vapour (reaching 100 percent relative humidity) saturates a portion of the atmosphere so that the water condenses and ‘precipitates’ or falls. Fog and mist are thus not precipitation, but colloids, since the vapour of water does not condense enough to precipitate. Two processes may contribute to air being saturated, likely working together: cooling the air or adding water vapour to the air. As smaller droplets coalesce through collision with other rain drops or ice crystals within a cloud, precipitation forms. Quick, heavy bursts of rain are called “showers” in scattered areas.

Precipitation is a significant component of the cycle of water and is responsible for the accumulation of much of the planet’s fresh water. Per year, about 505,000 km3 (121,000 mi3) of water falls as precipitation, 398,000 km3 (95,000 cu mi) of it over the oceans. Given the surface area of the Earth, this means that the annual precipitation is 990 millimetres (39 in) globally averaged.

Frequently Asked Questions – FAQs


Why do precipitation reactions occur?

When a solution containing a particular cation (a positively charged ion) is combined with another solution containing a certain anion (a negatively charged ion), the formation of an insoluble compound can often occur. A precipitate is considered the solid that divides.


Is precipitation a sign of a chemical reaction?

The formation of a precipitate also suggests the presence of a chemical reaction. When a silver nitrate solution is poured into a sodium chloride solution, a chemical reaction occurs, producing a white silver chloride precipitate.


What is an example of the formation of precipitate?

When a silver nitrate solution is poured into a sodium chloride solution, a chemical reaction occurs, producing a white silver chloride precipitate. A yellow lead(II) iodide precipitate is formed when the potassium iodide solution reacts with the lead(II) nitrate solution.


Is Salt a precipitate?

The insoluble salt falling out of the solution is referred to as the precipitate, hence the name of the reaction. Precipitation reactions in the solution can help to determine the identity of different ions.


What factors affect precipitation?

Prevailing waves, the presence of mountains, and seasonal waves are the 3 major factors that influence precipitation. Mountain ranges are a series of mountains interconnected by high soil. Where precipitation occurs, a mountain range in the direction of prevailing winds can also determine.


What is precipitation?

Precipitation is a phenomenon in which condensed water vapours fall on the earth’s surface under the influence of gravity in the form of rain, hail, snow or sleet.

How does the temperature affect precipitation?

The temperature may affect the precipitation of a chemical reaction. When we increase the solution’s temperature, the solubility of the ionic compound increases. Thus, decreasing the precipitate formation.

Can a precipitate be soluble?

No, a precipitate can never be soluble.

What is chemical precipitation?

Chemical precipitation turns liquid into solid by turning it into an insoluble form or by supersaturating the solution. It removes ionic constituents from water by adding counter-ions to reduce solubility.

What is the heat of precipitation?

The heat of precipitation refers to the change in energy when one mole of precipitate is formed from its constituent ions.

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