What is Condensation?
Condensation is the process of change of the phase of water where the vapour transforms to the liquid state. Condensation can be achieved in one of the following two ways :
- The cooling of air until its dew point.
- Saturation with water vapour until the point that it cannot hold any further quantity of water.
Condensation is considered to be the reverse reaction of evaporation, where the liquid water turns to a vapour state. The rate of condensation can be measured through the process of evaporation into the air moisture at various atmospheric pressures and temperatures. The process of condensation to involve the reaction where two molecules are combined together accompanied by the loss of water droplets. It also involves the removal of heat from a system where the vapour is converted into liquid.
Water Cycle
The formation of clouds is due to the occurrence of the process of condensation in the atmosphere. The water vapour contained in the atmosphere remains in the air. The molecules of water are in constant movement between the different states of matter- that is solid, liquid or gas. The vapours present in the air are loosely bounded to each other and in a state of constant random movement. When excess moisture collects in the air-water molecules become more organized. As an effect of this heat is released into the atmosphere accompanied by the phase change from vapour to liquid. The warm air first rises up and then cools down in the form of rain.
Dew Point
Dew is the water condensed in the atmosphere. The temperature at which the process of condensation occurs is known as the dew point. There are various applications visible with respect to the dew point:
- Cars and houses are mostly covered with water droplets early in the morning. This is because the air temperature at night stoops down below the dew point naturally.
- There are water droplets observed outside the surface of cold glass. This is because when the warm air outside comes in contact with the cold surface, it reaches its dew point and condenses.
- Forming of clouds in the atmosphere. Clouds have flat bottoms due to which the condensation starts. The flat bottom is the point where water vapour condenses to form water droplets.
Why condensation occurs?
Condensation occurs at high pressure and low temperature. Whenever the pressure of the liquid state of the gas is lesser than the pressure of the condensing gas, the process of condensation occurs. During this, there is release of heat energy, resulting in the transformation of the state of matter.
The process easily takes place around dust particles or smoke or microscopic bacteria. The atmosphere should be fully saturated in order to attain the level of maximum vapour pressure.
Saturation
Clouds can be considered as a mass of water droplets formed in the atmosphere. The water particles are situated far from each other in the atmosphere. Whenever more droplets combine in the clouds, they attain the point of saturation with the water vapour. Whenever more water droplets collect in the clouds, they become saturated. They cannot contain any more water vapour on increasing the density. This increases the closeness of the water molecules. This results in the condensation of water vapour and the formation of rain.
Warm climates are often considered to be more humid than cold weather. This is because cold air contains fewer vapours in comparison to warm air. The main reason behind this is that the water vapour remains in the air instead of condensing into the rain. In cold climates, condensation is easy.
Applications of condensation
- Formation of clouds and water cycle – Water balance in the environment is maintained by the process of condensation.
- Manufacturing of pure substances and separation of mixtures. Used in industrial processes.
- Morning Dew – Condensation of moisture present in the air and its condensation on grasses overnight.
- Fog on the mirror – After a hot shower, the shower moisture condenses on the cool mirror.
- Water droplets on the can.
- Clouds
- Foggy breath – Cold weathers allow your inner moisture to condense into large droplets.
- Foggy windshield – The moisture in the surrounding gets captured on the cold windshield, which condenses in the form of water droplets.
Sample Questions
Question 1: Differentiate between evaporation and condensation.
Answer:
| Evaporation | Condensation |
| Water changes into vapour in evaporation. | Water vapour changes into water in condensation. |
| Occurs before a liquid reaches its boiling point. | Remains unaffected by the temperature. |
| Consumption of energy takes place. | Release of energy takes place. |
| Weak force of attraction between the molecules. | Strong force of attraction between the molecules. |
Question 2: Explain the sequence of occurrence of Evaporation and Condensation?
Answer:
The process of evaporation occurs first, which leads to the formation of water vapour in the atmosphere. These water droplets then collect and cool down to cause condensation.
Question 3: How can condensation be avoided at home?
Answer:
It is possible to avoid the process of condensation by making proper ventilation spaces for the moisture to escape during activities, like cooking and showering.
Question 4: Explain the harmful effects of condensation.
Answer:
There are some serious side effects of condensation:
- Fungus and mildew growth
- Blistering or peeling paint
- Damp spots on ceilings
Question 5: Explain the cause of condensation.
Answer:
When the warm air comes in contact with the cooler surfaces the excess of the moisture undergoes condensation. The reason behind this is that the excess moisture can’t be held on the cooler surface.
Question 6: The cup that is exposed to more air has more water on the outside of it than inside. Explain why?
Answer:
Water vapour is one of the gases that make up air. The moisture is a result of the vapour cooled down on the surface. The cup in the bag has very little moisture on it because it is exposed to much less air, which thereby indicates the presence of less vapour.
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