15 Vapor Pressure Example: Detailed Facts

The vapor pressure is a force exerted on the area or the surrounding region.

The vapors are small liquid droplets in the gaseous form formed as the heat energy is utilized to overcome the intermolecular forces of attraction between the molecules constituting a liquid state. Here is a list of vapor pressure example:-

Boiling Water

Upon boiling water, the heat energy is supplied to the water and it boils till the temperature reaches the boiling point i.e. 1000 C.

At this temperature, the molecules break the intermolecular forces of attraction between the water and then the water turns into a vapor state. At this point, the vapor pressure becomes equal to the surrounding pressure and acquires saturated vapor pressure.

Boiling Tomatoes; Image Credit: Pixabay

Cooking Food

You must have noticed the vaporization in the form of the tiny vapors. This is because the water added while cooking food reaches the boiling point of the water and the water starts converting into a vapor state.


During the Sun, the surface layers of the water get heated up and molecules present on the layer of water gain kinetic energy. Therefore, this energy is given out as these molecules with high energy succeed in breaking the bond and evaporate in the form of water vapors. As the vapor rises higher and higher it gains more and more potential energy.

Volcanic Eruption

The molten magma is at high pressure under the depths which when erupts and comes on the normal atmospheric pressure, the volatile matter is given off in the form of vapors.

A cluster of ash and vapors during the eruption; Image Credit: Pixabay

This is because the temperature of the magma is tremendous above the thousand Kelvin thus giving away the heat energy in the surrounding area.

Pressure Cooker

Inside the pressure cooker, the pressure felt is above 1atm, and thus the boiling point of the liquids increases. As the temperature of a liquid rises above the boiling point then the phase transition occurs and the vapor pressure thus developed is given out from the cooker lid.


The electrical steamers produce the steam as the water boils at the boiling point.

Steam from the kettle; Image Credit: Pixabay

At this temperature, the phase changes from liquid to the vapor and this steam flows out due to vapor pressure.

Ice kept in a Bucket

You must have noticed at the small droplets of vapor initially settle down on the container filled with ice cubes and then turns into the liquid drops.

Condensation of vapors on glass surface; Image Credit: Pixabay

This is because the ice cubes grasp the heat energy from the surroundings and utilize it to break the molecular bonds to change the phase from solid to liquid. Hence we find the vapors settling on the outer surface of the container as the molecules condense due to the cool temperature.

Alcoholic Chemical

These chemicals are highly volatile liquids and can easily convert into vapors. That is why we can smell the alcoholic chemicals from a distance as the vapors are carried in the surrounding atmosphere. As they are very volatile they can easily catch fire.

Gas Cylinder

The gas cylinders are filled with liquid petroleum gas.

Pressure Valve of a cylinder; Image Credit: Pixabay

The fuel is supplied from the cylinder to the burner because of the vapor pressure. The knob is used to close and open the valve to allow the gas vapors to pass to the burner.


The drying is possible because of the evaporation of the liquid soaked in the wet objects. The heat energy from the surrounding is absorbed by these molecules of water. Due to this, the water molecules evaporate in the form of vapors thus the vapor pressure comes into the scene.

Exfoliations of Rocks

The rocks are made up of different chemical components and do soak water molecules in them required for erosion for chemical weathering. These rocks when exposed to the hot sun, the water molecules escape from the rocks in the form of vapors, thus resulting in the exfoliations of rock.


A frost is formed in the refrigerator. The temperature in the middle region of the refrigerator is cooler than on the surfaces hence the cool air breeze from the middle to the surface of the refrigerator thus accumulates the water vapors at the surface and thus solidifies to form a frost which is called false ice because it is made up from the condense vapors.

vapor pressure example
Frost on glasses due to condensation of gas; Image Credit: Pixabay

The food items or the water kept in the freezer will give out the vapor as the temperature inside the freezer is less compared to the heat energy present with these items. This heat energy is given off in the form of vapor.


The fog during the winter season is formed due to the evaporation of vapors from the green leaves and from the water bodies as well. The vapor pressure formed in the foggy winter depends upon the density of the vapors in the region. If the density of the vapor is very high then the vapor pressure in this region intensifies.


The waterfall is an example of the mechanical energy of the water which is a combination of kinetic as well as the potential energy of the water. As the waterfall accompanies by the kinetic motion of the water, the molecules of the water associate the kinetic energy. This energy is given out from the volume of water and also due to the abrasion.

Evaporation of water vapor at Niagara falls; Image Credit: Pixabay

These molecules escape from the water body and remain wandering in the surrounding atmosphere until it settles on the surrounding object or evaporates into the atmosphere at high altitudes.

Air Conditioners

As the air enters from the base of the machine it runs through a pipe where the coolant liquid is circulating. This air is compressed by the compressor due to which the gas turns into the vapor form which is then run to the condenser to cool down the liquid and then again the liquid is turned into the gas through the expansion valve.

Frequently Asked Questions

How vapor pressure depends upon the heat enthalpy?

The heat enthalpy is nothing but the heat energy required to break the bonds between the atoms.

The heat enthalpy is very important for phase transition. A lot of heat energy is essential to break the bonds and convert liquid into the vapor state. The density of vapor will exert the vapor pressure in the surrounding area.

What is meant by saturated vapor pressure?

The saturated vapor pressure is the highest vapor pressure maintained by the liquid kept at that atmospheric condition.

The saturation vapor pressure is achieved at the final boiling point of the liquid above which the temperature of the liquid does not rise and therefore the number of vapors formed at this temperature remains the same as the vapor on vaporization gets cool down and condenses.

Does the vapor pressure change with the rising volume of the liquid?

The volume of the liquid does not affect its vapor pressure.

The value of the vapor pressure remains the same whether you increase or decrease the volume of the liquid but at the same temperature.

At what temperature does the vapor pressure reach its equilibrium state?

The vapor pressure is in an equilibrium state as the temperature of the liquid reaches the boiling point.

At boiling point, more and more vapors formed get cool giving away the heat energy in the surroundings, and then gets condense forming small liquid drop, thus vapor pressure becomes equal to the atmospheric pressure.


Hi, I’m Akshita Mapari. I have done M.Sc. in Physics. I have worked on projects like Numerical modeling of winds and waves during cyclone, Physics of toys and mechanized thrill machines in amusement park based on Classical Mechanics. I have pursued a course on Arduino and have accomplished some mini projects on Arduino UNO. I always like to explore new zones in the field of science. I personally believe that learning is more enthusiastic when learnt with creativity. Apart from this, I like to read, travel, strumming on guitar, identifying rocks and strata, photography and playing chess. Connect me on LinkedIn - linkedin.com/in/akshita-mapari-b38a68122

Recent Posts