What is Condensation? Definition, Meaning, Water Cycle, Examples, Reactions

In this article, we will learn all details about what is condensation, its definition, meaning, reactions, process, different forms, applications, advantages, disadvantages, etc. Let’s explore!

What is Condensation? Definition 

Condensation Definition

Let’s try to understand the definition of condensation. The natural phenomenon in which vapors turn back into liquid is known as condensation, which is contrary to the process of evaporation. Similarly, it can also be defined as the reaction in which water loss occurs, combining two water molecules. Additionally, it is also described as a mechanism that results in heat loss from a system due to vapor conversion into liquid.

Condensation Meaning

The condensation point is similar to the boiling point, i.e., 100 degrees Celsius (212 degrees Fahrenheit). In the process, the liquid or solid (from their vapor state) deposits on a relatively cooler surface than the adjacent gas.

  • The process happens every day around us. Some everyday examples of condensation are dew drops, droplets on a can of cold drink bottles, foggy mirrors, foggy breaths, and, most importantly, clouds.
  • Both the clouds and foggy breath are examples of condensation occurring without a surface.
  • Cloud formation is an essential aspect of the water cycle in which condensation is a significant process. 

How Does Condensation Work? 

The basic principle behind condensation is the state change in which the water or liquid changes from vapor or gas to liquid form.

  • Water constitutes molecules.
  • These molecules are characterized by fast motion, higher energy, and being far away from each other in case of vapors.
  • But when these vapors strike cooler surfaces or temperatures, they slow down.
  • As a consequence of which they are now less energetic and come closer to each other.
  • The vapors reaching the threshold energy level transform into the liquid.

It’s the whole principle behind condensation. 

Process of Condensation  

Condensation takes place when water changes its phase from a gaseous state to a liquid or crystal shape. Gas or vapors can condense at a higher pressure and lower temperature. Condensation takes place irrespective of temperature as long as the liquid state of the gas has a pressure less than the condensing gas pressure. Heat loss occurs during condensation; therefore, The molecules in the matter slow down, causing a change in the state of matter from vapor into liquid.  

  • A fundamental example of condensation is a cold water bottle.
  • The temperature of the bottle is cold due to the cold water inside it.
  • The air has moisture (humidity), and the air molecules in the surrounding will continuously hit the bottle from outside in Omni direction.
  • The cool bottle causes the air surrounding it to become colder.
  • Hence, the air with humidity cannot hold more water particles when closer to the bottle.
  • That’s how condensation takes place.
  • The moisture or vapors change into liquid (gas transforming into liquid).

Condensation Reactions 

In terms of chemistry, a condensation reaction involves a combination of two molecules, resulting in the release of a small molecule. If the lost molecules are water, the process is termed dehydration reaction. However, there is a possibility of releasing other molecules such as methanol, acetic acid, and HCL. 

  • A condensation reaction is a chemical reaction in which two molecules combine to form a larger one and a water molecule.
  • Condensation reactions involving alcohols, as well as many other molecular types, commonly occur in living organisms.

Now the two types of condensation reaction are intramolecular and intermolecular condensation. 

Intermolecular Condensation Reactions

When two separate molecules react, we call it intermolecular condensation; For instance, the condensation of two amino acids forming a peptide bond.

  • In this process, the dehydration of amino acids leads to peptide bond formation and water release.
  • The mechanism is the reverse of hydrolysis. 

Intramolecular Condensation Reactions

Intramolecular reactions involve condensation between different parts of the same molecule, leading to ring formation.

  • The most common example is when two ester groups of a single ester molecule react, losing a small alcohol molecule and forming a β-ketoester product known as Dieckmann Condensation. 
  • Condensation reactions commonly follow a nucleophilic acyl substitution or an aldol condensation reaction mechanism, while radical conditions set off other condensations like acyloin condensation. 

Condensation Polymerization Reactions

The condensation polymerization reaction is the type of polymerization that comprises a series of condensation steps where monomer or monomer chains combine, forming long chains. The mechanism is also termed “step-growth polymerization.” The most common example which involves this process is polyester or nylon synthesis. 

  • For instance, if we take the example of nylon, it comprises repeating units joined with amide bonds; therefore, it is often referred to as polyamide.
  • The condensation reaction may be homopolymerization or copolymerization, and Diacid and Diamine condensation is homopolymerization.
  • The condensation polymers are lower in weight than the additional polymers.
  • The condensation polymerization reactions are widely used to produce important polymers like nylon, polyester, epoxy, etc. 

Cooling Processes Producing Condensation 

The cooling processes that produce condensation are studied in terms of Adiabatic Temperature changes and Non-adiabatic Temperature changes. 

Adiabatic/Katabatic Temperature Changes 

Adiabatic temperature changes are concerned with pressure changes without external gain or loss of heat. The phenomena can be explained by incompressible fluid (e.g., seawater); the temperature will rise when fluid is compressed, and adiabatic cooling occurs during expansion. The major cause of adiabatic temperature changes is the vertical displacement of air. 

Non-Adiabatic/Diabatic Temperature changes

Non-adiabatic temperature change is not related to the vertical displacement of air, and most temperature change processes are non-adiabatic near the earth’s surface. Diabatic temperature change produces cooling through radiation, conduction, or mixing with cold air. The cooling can produce fog, dew, or frost, subject to hygroscopic nuclei in the atmosphere. 

Hygroscopic Condensation Nuclei

The concept of Hygroscopic condensation nuclei is very important in the mechanism of condensation. Starting with particle physics, let’s dive into understanding Hygroscopic Condensation nuclei.

  • Consider a solid block.
  • The structure is made up of molecules.
  • These molecules are formed when atoms are combined.
  • Atoms are the smallest unit of matter.
  • There are subatomic particles inside the atom (proton, electron, neutron).
  • These subatomic particles combine to form a nucleus which is the central part of the atom.
  • Hence nuclei (singular nucleus) are an essential part of the matter. 

Now, discuss the water droplets which formed during condensation. A water droplet has a central nucleus that holds it in drop form—now, coming towards the nuclei. What are these nuclei?

They are small dust or smoke particles or salt of sea and ocean, and the term used for them is aerosol. These aerosols are capable of holding and attracting water molecules from the surrounding. That’s how the term “hygroscopic” came into being. In simple words, Hygroscopic condensation nuclei are responsible for holding water in the form of drops.

Forms of Condensation 

The forms of condensation can be categorized based on the dew point. The condensation forms are classified based on location, free air, and near the earth’s surface. Mist, fog, white frost, haze, smog, and dew belong to the first category (free air), and on the contrary, clouds are from the second category (near the earth’s surface). Each of these forms of condensation is discussed below. 


Dew is moisture deposited in water droplets on cool solid surfaces like grass blades, stones, plant leaves, etc. The most favorable conditions for its formation are high humidity, calm air, clear sky, cold and long nights. Their formation occurs whenever the dew point is higher than the freezing point. 

White Frost 

When condensation occurs below the freezing point (0 degrees celsius) on cold surfaces, it results in the formation of white frost. The most favorable condition for white frost is when the dew point is lower than the freezing point. High humidity, calm air, clear sky, cold and long nights, and air temperature at or below freezing point contribute to white frost formation. 


Condensation takes place on fine dust particles when the temperature of an air mass containing many water vapors suddenly falls. It results in the formation of fog that resembles clouds but is very near the Earth’s surface. Fog results in poor or sometimes zero visibility, and it has several types. 

  • Radiations, cooling of ground and adjacent air result in radiation fog which is pretty usual in winters and is not very thick.
  • When warm air moves horizontally on a cold surface, condensation occurs, resulting in fog formation called advection fog.
  • They are common over warm and cold water mixing zones in oceans, and such fogs are thick and persistent.
  • Warm air masses are pushed under due to heavy cold air masses, resulting in frontal fog formation, also known as precipitation fog. 


Mist is similar to fog, and the slight difference is that smoke contains more moisture than fog. It is most frequently formed over mountains when the warm air rises the slopes and meets a colder surface.

  • Mist also results in lower visibility, but the visibility is better than in a fog, and mist is less dense and quickly dissipates.
  • Urban and industrial areas significantly from mist and fog. 


When condensation takes place in free air at considerable elevations, it results in the formation of clouds. The primary cause for cloud formation is the adiabatic cooling of air below its dew point.

  • As we know, clouds are present at some height from the earth’s surface, changing shapes.
  • Clouds are of four types based on their opaqueness, density, height, transparency, etc.
  • They are; cirrus, cumulus, stratus, and nimbus. 

There are several forms of condensation. However, the above explained are some of them. 

Condensation in Water Cycle

Let’s try to understand the water cycle in condensation. Condensation is opposite to evaporation, playing a critical role in the water cycle. It aids in cloud formation while it further supports precipitation which is a way for the water to return to Earth’s surface.

  • The clouds are not always visible in the sky, but water droplets are always present and are invisible to us.
  • Depending on the weather conditions, water droplets combine with minute dust, smoke, and salt particles in the air.
  • They further grow and form clouds in the sky. Cloud droplets vary in size ranging between 10 microns-5mm.

The phenomenon takes place at high points in the sky where the air is cool. Hence more condensation occurs than evaporation. The formation of clouds is vital as it helps regulate the flow of energy into and out of the climatic system of planet Earth.

The reasons for condensation are; either air is cooled to its dew point, or it becomes saturated such that it can no longer hold any water. Therefore, cloud formation, aided by condensation, is essential in the water cycle. The rain would not be possible if there were no clouds and condensation.

Is Condensation an Endothermic or Exothermic Process?

Condensation is among the natural phenomena involved in heat exchange. In science, reactions involving heat transfer are broadly categorized as Exothermic and Endothermic processes. Taking into consideration, Condensation falls under the category of exothermic reactions. Reactions releasing heat to surroundings are exothermic. At the same time, those absorbing heat are endothermic reactions.

The condensation process is such that one would say it’s not exothermic by simply observing as heat release is not very obvious. However, the phenomenon involves the escape of high-energy molecules from a liquid state into a vapor state. When these molecules lose energy to the surroundings, they turn back into liquid. That’s how the release of heat to the surroundings takes place. Hence, condensation is an exothermic process.

Condensation on the Inside of the Windows

Condensation on windows is a common phenomenon that occurs under certain conditions of temperature and moisture. Compared to a wall having inner and outer panels separated by a cavity filled with insulation, window panes are pretty vulnerable to outside temperatures.

While maintaining an internal warmer temperature inside buildings or homes, the windows will remain the coldest areas. It is because the window is in direct contact with the outside environment and takes place when moist air comes in contact with the cool and dry air.

Generally, condensation in closed areas occurs when the outside air is cold. It occurs mainly in winters when steam releases.  The process is very prevalent on windows and indicates a positive sign. It points out strong insulation in a building and home while not letting the moisture escape.

Condensation in Condensers 

The devices which reduce gas or vapor to liquid are known as condensers, and they are primarily present at power plants for condensing exhaust steam from turbines. Moreover, in refrigeration plants, it is used to condense refrigerant vapors like ammonia and fluorinated hydrocarbons. Condensers come in variants that are indirect and direct. 

Indirect Condensers 

In indirect condensers, the air to be treated is passed through a liquid-gas heat exchanger. In this way, the cooling medium is separated from the gas stream that is treated. It is advantageous to use this variant because it results in no pollution. Moreover, the solvent doesn’t need to be separated from the cooling medium through a separating stage. 

Direct Condensers

In Direct condensers, there is direct contact between gases and the cooling medium, resulting in excellent heat transfer. Such condensers are generally fitted as spraying chambers and are primarily used for gas streams that can intensively pollute heat exchangers. 

Applications of Condensation

Condensation is a naturally occurring phenomenon that plays a vital role in nature. Moreover, many artificial processes are also based on this process. Some applications of condensation are given below. 

  • Condensation is an important phenomenon in the water cycle, and it results in cloud formation. The condensed droplets forming clouds get bigger and heavier and fall to the ground as rain. 
  • Similarly, snow and sleet formation is also associated with condensation along with precipitation. 
  • Condensation polymerization reactions are widely used in some industries. The most crucial condensation polymer formed by these reactions is nylon.
  • Nylon is utilized in making all types of clothes.
  • Nylon is not suitable for warm weather; therefore, industries combine nylon with cotton or other synthetic fibers to produce clothes that can effectively absorb moisture. Hence, now ideal for warm weather.
  • The condensation polymerization reactions also produce terylene, and it is used in manufacturing synthetic textiles. Terylene retains crease and is quite soft.
  • The sailboats use woven terylene in their making.
  • The condensation of Urea with methanal forms urea-methanal resins. Urea methanal is used in electrical fittings and kitchenware, and it also prepares a form used for heat insulation. 
  • Melamine-methanal resins form when melamine condenses with methanal. They are manufactured in different appealing colors. Melamine methanol can make unbreakable cups, bowls, plates, and heat-resistant cups. 
  • Condensation polymerization reactions also produce phenol methanal used in plugs, switches, utensil handles, radio housing, sockets, telephone casings, etc. 
  • Condensation polymerization is a natural phenomenon occurring inside living organisms also. Natural polymers inside living things play important structural and functional roles. The main polymers are carbohydrates and proteins, and they are essential to sustain life.
  • Condensation phenomena are present in air wells and fog fences used for retaining soil moisture in areas where desertification is a significant issue. 
  • Condensation is widely in use commercially, for instance, thermal management, water desalination, power generation, refrigeration, air conditioning. 
  • In some areas all over the world, humans make water available using condensation. 
  • Condensation can form contrails, i-e artificial clouds. 
  • Condensation reactions are important in organic chemistry. 
  • The process can form silicates and polyphosphates in the laboratory. 
  • Several biological transformation processes use condensation like polypeptide synthesis, polyketide synthesis, terpene synthases. Moreover, phosphorylation and glycosylations are all based on condensations.
  • Flue gas condensation systems are industrially in use to prevent the detrimental icing effects in several stages. 
  • Cooling water systems are used in steam condensation systems for generating waste streams in coal and natural gas combined-cycle plants

Advantages of Condensation

The advantages of condensation are as follows:

  • Condensation allows the falling of water on the ground in the form of precipitation. It is helpful in agriculture because farmers rely significantly on the mechanism to depend less on irrigation. 
  • Condensation causes rain. If the phenomena didn’t exist, molecules wouldn’t condense, floating away and not being available for living creatures. 
  • The process has industrial and commercial use in many things. 
  • It can help in producing several condensation polymers having applications in different industries. 
  • Water would exist in gaseous form without condensation and won’t be suitable for consumption. 
  • The phenomenon is employed in the petroleum industry. 
  • The process has growing application in the greenhouse because it dramatically influences the light output. 
  • Condensers are widely used in power plants in several industries. 

Disadvantages of Condensation

The disadvantages for condensation are listed below:

  • Fog and mist form due to condensation. Fog can reduce visibility up to 2 kilometers and mist up to 1 kilometer. It can cause road accidents and is also impactful on other everyday outdoor activities. 
  • Condensation is harmful in construction, and it results in dampness, rotting of wood, corrosion, mold health problems, etc. 
  • It results in increased humidity in homes and other places. Ventilation is crucial to control it. 
  • Condensation deposits moisture on windows, resulting in soggy spots over drywall and insulation at homes and in buildings.


Condensation is a naturally occurring phenomenon. It plays a vital role in the water cycle because it forms clouds and causes rain on Earth. The mechanism is present in reactions like condensation polymerization reaction, which produces polymers with many advantages in industries. The phenomenon is opposite to evaporation. Condensers are devices used widely in petroleum and other sectors to reduce gas or vapor to liquid. It comes in variants known as indirect and direct condensers.

The working principle behind this mechanism is state change that is from vapor or gas to liquid. There are various forms of condensation governed by different conditions favorable for their formation—moreover, categorized depending upon their location i-e free air or near the earth surface. These forms can also be classified according to dew point and freezing point. The process has worldwide usage, as discussed above in the applications section. Additionally, the advantages and disadvantages are also discussed in-depth in the blog. Any questions on condensation or condensation definition?


Hello Everyone! We, Rituparna Guha & Firan Mondal, are delighted to present our Mechanical Engineering articles. We will capture all types of articles and try to explain in the simplest way with a lot of diagrams! Happy Reading....

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts