In general, a material can exist in mainly three different forms. A group of from that is collectively known as the states of matter. On the other hand, under certain conditions, these forms of matter can undergo a physical process. A process we refer to it as a phase transition.
For an instance, the solid to the liquid phase transition is known as the process of melting. Or, liquid to the gas phase transition is known as the process of evaporation.
Similarly, for the gas to a liquid phase transition, we refer it as a process of condensation. As a matter of fact, in this article, we are only interested in the process of evaporation.
Not to mention, there is one more distinct type of phase transition in which an intermediate phase can be skipped. One of them is the process of sublimation.
In science, Evaporation is a type of phase transition during which a matter changes from liquid to its gaseous form. This type of phase transition comes in the category of surface phenomena. WHY?
Because, unlike boiling, this process can occur at any temperature, of course, below boiling point. In other words, the process of evaporation occurs before a liquid (say water) reaches its boiling point.
Not to mention, the higher the temperature, the higher will be the rate of evaporation. Moreover, this process comes under the category of the endothermic phenomenon.
The opposite of evaporation is known as condensation. In other words, when a matter changes from gas (vapor) to its liquid form, known as condensation.
Just to make things a bit more clear, when there is liquid to a gas phase transition, by definition, we call it evaporation. On the contrary, when there is gas to a liquid phase transition, we call it condensation.
In fact, the main difference between evaporation and condensation is that evaporation is a cooling process. While, on the other hand, condensation is a warming process.
Evaporation Process: A cooling phenomena?
According to the conventional definition of kinetic theory, the addition of heat allows the material to gain a substantial amount of energy.
An energy that is used by the molecules of a material to overcome the attractive forces between each other. Hence, particles or simply molecules can become loosely bound to each other.
During the process of evaporation, in order to accomplish liquid to a gas phase transition, a liquid has to absorb a sufficient amount of heat or energy from its surroundings. Hence bringing down the temperature of the surroundings.
In other words, when liquid (say water) evaporates, it takes up energy from its surroundings, therefore, cools the environment. That’s why the physics of evaporation comes in the realm of endothermic processes.
This process is also known as the cooling effect of evaporation. For example, Evaporative coolers specifically show that evaporation is a cooling process.
Editor’s Choice: Endothermic vs Exothermic – What’s the Difference?
Factors that Affect Evaporation
There are numerous factors that affect the rate of evaporation. Some of them are explained below!
Temperature is the most common factor that can easily influence the rate of evaporation. The higher the temperature, the higher will be the rate of evaporation.
In fact, mathematically, you can say that temperature is directly proportional to the rate of evaporation. For example, the drying of wet clothes under direct sunlight.
In a wet and humid atmosphere, the rate of evaporation decreases drastically. In other words, If the amount of water present in the air is already at its threshold, the rate of evaporation will be slow.
Mathematically, humidity is inversely proportional to the rate of evaporation. For example, in the rainy season, wet clothes won’t be dried easily.
The larger the surface area, the higher will be the rate of evaporation. That’s why evaporation comes in the category of surface phenomena.
Mathematically, the surface area is directly proportional to the rate of evaporation. For example, the larger the pond, the more water will evaporate from its surface.
Some other factors include:
- Wind Speed
- The concentration of the material evaporating
- Inter-molecular forces, etc.
If you think, you can’t relate to evaporation examples in daily life. Well, here is your chance to think again…!!!
- Evaporative Coolers
- Drying of Wet clothes
- Working of a pressure Cooker
- Formation of salt
- Melting of ice cubes
- Formation of the water cycle
- Evaporation of sweat from our body
- The smoke coming out of a cup of hot coffee
- Food preservation
- Evaporation of a nail paint remover
- Evaporation rate of ethanol
- Drying of a wet floor
- The process of distillation
- Drying of river beds
- Ironing of clothes, etc.
Frequently Asked Questions
1. What is Evaporation?
Ans. In science, Evaporation is a type of phase transition during which a matter changes from liquid to its gaseous form.
2. What is the evaporation rate of water?
Ans. There are numerous factors that can affect the rate of evaporation of water. Apart from that, the evaporation rate of water is usually expressed as the water depth lost in millimeters over a period of time.
For example, if I am talking about a period of a single day, the rate of evaporation of water is 2mm/day. Similarly, for a week, it will be 14mm/week, etc.
3. What is the evaporating temperature of the water?
Ans. There is no denying that the evaporation of water can occur at any temperature. However, at the boiling point i.e at 100° C, the rate of evaporation of water is at its peak.
4. What is the difference between boiling and evaporation?
Ans. The primary difference between boiling and evaporation is the process of evaporation results in cooling. While, on the other hand, the process of boiling does not result in cooling.
Additionally, evaporation is a surface phenomenon. On the other hand, the process of boiling can occur throughout the liquid.