Differences between Evaporation and Boiling in Chemistry

While you might think that chemistry is all about chemical processes occurring in real-world or laboratory settings, this isn’t the case. In fact, chemistry incorporates many physical processes in which the form of the matter changes but the composition of the substance remains unaltered. Two common examples of a physical change are evaporation and boiling. 

Although evaporation and boiling may seem to be quite similar, these are two different physical processes we encounter in chemistry. 

But how do these processes differ from each other? Here’s the answer for you. 

In this article, we explain evaporation and boiling while sharing a few everyday life examples of each process. In addition, we provide the key differences and similarities between evaporation and boiling in chemistry.

What Is Evaporation?

You may have heard that evaporation, along with condensation and precipitation, is one of the main stages of the water cycle. But what is evaporation?

Evaporation is a physical change in which a liquid turns into a vapor. During evaporation, a substance changes its state and transforms from a liquid phase to a gaseous phase. 

Evaporation is a process that can take place at any temperature above 0oC. Whether the temperature is low or high, substances will eventually evaporate. However, the rate of evaporation is lower in low-temperature settings. As we increase the temperature, the evaporation rate increases as well. 

What Are the Uses of Evaporation?

Evaporation is widely used during experiments in laboratories and for industrial purposes as well. 

Evaporation is used for the production of liquid concentrates in the pharmaceutical industry, is involved in the food processing industry, is essential for salt extraction from seawater, and is used for the purification of organic chemicals. 

Here are a few common applications of evaporation in different industries. 

#1. Evaporation Is Used in the Pharmaceutical Industry for the Production of Liquid Concentrates

Since the primary role of evaporation is to concentrate a solution by evaporating a portion of the solvent, the process is widely used for the production of liquid concentrates in the pharmaceutical industry. By removing excess moisture through evaporators, scientists manage to create more stable drugs, preventing or reducing the rate at which certain components decompose. 

#2. Evaporation Plays an Important Role in the Food and Beverage Industry

Along with dehydration, the food processing industry widely uses evaporation to remove excess water and moisture from food products. Evaporators are often used to pre-concentrate food, which not only increases the solid content of products but can also change their color. That being said, evaporation is widely used in the production and processing of milk, coffee, fruit juices, vegetable pastes, sauces, edible oil, and more. 

#3. Evaporation Is Involved in the Extraction of Salt from Seawater

In order to extract salt from seawater, salty lakes, or other mineral-rich sources, salt farmers create artificial basins. These are shallow ponds designed to evaporate water and retrieve salt. So the primary means of salt extraction from seawater is evaporation. 

#4. Evaporation Is Used for the Purification of Laboratory Chemicals

There are several separation and purification methods used in the lab, and evaporation is one of them. Evaporation is often used for the purification of laboratory chemicals, especially organic compounds. The process is used for purifying a compound that had been dissolved in another one. By vaporizing a portion of the solvent in a solution, you get a purified solute. This article discusses further details about separation and purification methods used in chemistry. 

Everyday Life Examples of Evaporation

To better understand the concept and importance of evaporation, let’s discuss a few common examples of evaporation that we encounter on a daily basis.

Everyday life examples of evaporation include:

  • Wet clothes drying under the sun
  • Using a hairdryer to dry your hair
  • Ironing slightly damp clothes
  • Hot drinks/liquids cooling down
  • Sweat evaporating from your body on a hot summer day
  • Rain puddles evaporating on a hot day
  • Floors drying up after mopping 
  • Acetone evaporating from your nails when removing nail polish
  • Hand sanitizer drying quickly after sanitizing your hands
  • Steam forming by evaporation during cooking
  • Water evaporating when a glass of water is left under the sun
  • Water evaporating into steam when boiling water in a kettle

As you can see, evaporation occurs during a myriad of activities we perform in our everyday lives. 

What Is Boiling?

You’re most likely familiar with the term “boiling” as we all have boiled some water when cooking or drinking a cup of coffee/tea. But what does boiling actually mean?

Boiling is a physical process during which a substance in its liquid form turns into its gaseous form when reaching its boiling point. 

Boiling occurs only when the temperature of a given substance hits its boiling point. The boiling point of a substance can be defined as the temperature at which the pressures exerted by the liquid vapor and the surroundings upon the liquid are equal to each other. 

What Are the Uses of Boiling?

Along with a broad range of residential applications, boiling has many uses for industrial purposes. 

Boiling is used in both basic and more advanced chemistry experiments conducted in laboratories. Boiling is also involved in various industrial applications, such as electric power generation. Obviously, boiling is used for daily cooking and food preparation. 

Here’s what you need to know about the applications of boiling. 

#1. Boiling Is Incorporated in Various Experiments Conducted in Labs

When scientists conduct experiments or synthesize compounds, they often boil different substances. It could be water or a broad range of other chemicals, typically organic compounds. Boiling is used not only for heating up substances but also for separating components of a liquid mixture through distillation. Whatever the case is, boiling plays a crucial role in various laboratory procedures. 

#2. Boiling Is Involved in Electric Power Generation

Generally speaking, electric power is generated by electrochemical generators. In some cases, electrical power is generated by means of boiling water reactors (BWR). This is a type of water nuclear reactor that heats water and produces steam inside the reactor vessel. 

#3. Boiling Is Used for Daily Cooking and Food Preparation

Last but not least, boiling is used when cooking and preparing food. Whether you’re boiling water to cook some pasta or you’re heating up your dinner, boiling is involved in the process. 

Everyday Life Examples of Boiling

Although you’re probably familiar with boiling, let’s discuss how boiling is used on a daily basis. 

Everyday life examples of boiling include:

  • Boiling water in a pot or in a kettle
  • Pressure cooking
  • Cooking with salt while increasing the boiling point of water
  • Boiling milk and creating a layer of fat and protein on its surface

While boiling seems to be a pretty straightforward process, keep in mind that considering boiling points of different substances is essential for safety reasons. 

What Are the Differences between Evaporation and Boiling?

Based on what we’ve discussed above, it’s quite obvious that evaporation and boiling are two completely different processes that might seem quite similar at first glance. To make it easier for you to differentiate between evaporation and boiling, let’s continue with the major differences. 

The main difference between evaporation and boiling is that evaporation can occur at any temperature while boiling requires reaching a higher temperature, the boiling point of a given substance. 

For detailed information about the differences between evaporation and boiling, check out this article by the National Science Teaching Association. 

Here are a few more differences between evaporation and boiling:

#1. Required Temperature

When talking about the differences between evaporation and boiling, we should always start by mentioning the fact that evaporation can happen at any temperature above freezing. On the other hand, boiling requires heating to a certain temperature, also known as the boiling point of a substance. 

#2. The Source of Energy

Since boiling requires reaching a higher temperature, it usually occurs when there’s an external source of energy present. It could be flames under the pot that allow you to boil some water. In contrast, evaporation uses the energy within the liquid that came from the environment. 

#3. Speed

Another difference between evaporation and boiling is that evaporation is a slow process and can take hours, days, or even weeks. While evaporation occurs gradually, it’ll take some time for water in a glass to evaporate completely. Contrarily, boiling is a much faster process. It only takes a few minutes to boil water or even other liquids. 

#4. The Way a Given Substance Changes the Phase

Besides, the location of the change from a liquid to a gas is also different when it comes to evaporation and boiling. In the case of evaporation, only the molecules on the surface of the liquid evaporate. On the other hand, boiling starts at the bottom of a vessel and bubbles continue to form throughout the entire liquid as it reaches the boiling point. 

#5. Temperature Change of the Substance

During evaporation, the temperature of a given liquid and the surface the liquid is evaporating from decreases. This explains the fact that we feel cold when sweat or water particles evaporate from our bodies. In the case of boiling, the temperature of a given liquid remains unchanged once it reaches its boiling point. For example, once the water reaches its boiling point, you can’t make it any hotter. 

#6. Bubble Formation

Last but not least, there are no bubbles formed during or as a result of evaporation. Contrarily, when boiling a liquid, the phase change is so rapid that the bubbles of liquid vapor form. 

The Summary of Differences between Evaporation and Boiling in Chemistry

Here are a few key factors that make evaporation and boiling two completely different processes. 

Evaporation Boiling
Evaporation can occur at any temperature above freezing. Boiling only happens at the boiling point of a given substance. 
Evaporation uses the energy within the substance that was obtained from the environment.  Boiling requires an external source of energy. 
Evaporation is a natural process. Boiling is an unnatural process.
Evaporation is slower.  Boiling is faster. 
Evaporation occurs on the surface of a liquid.  Boiling occurs throughout the liquid. 
During evaporation, the liquid and the surface it’s evaporating from will cool down.  During boiling, the temperature of the liquid remains constant at the boiling point. 
Evaporation doesn’t lead to bubble formation.  Boiling causes bubbles to form. 

Are There Any Similarities between Evaporation and Boiling?

Although evaporation and boiling are two separate processes, they have something in common. 

The main similarity between evaporation and boiling is that a liquid turns into vapor when the temperature and/or pressure is increased. 

At the end of the day, evaporation and boiling are two different physical processes that are of huge importance in chemistry. 

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