What is Boyle’s Law?

Boyle’s Law

The law Boyle was discovered by Robert Boyle in the seventeenth century, and it was the law that established the basis to explain the relationship between pressure and volume that exists in a gas . Through a series of experiments, he managed to show that, if there was a constant temperature , a gas when subjected to more pressure reduces its volume , while if the pressure decreases the volume increases .

What is Boyle’s Law?

Boyle’s law is a law related to gases that establish a relationship between the pressure and the volume that a certain amount of gas has , without variations in temperature , that is, at constant temperature.

  • What is Boyle’s law?
  • History
  • Who proposed it
  • Boyle’s law statement
  • Formula
  • Experiments
  • Applications
  • Importance
  • Examples of Boyle’s Law

What is Boyle’s law?

In the year 1662 Robert Boyle , discovered that the pressure that was applied to a gas was inversely proportional to its volume at constant temperature and number of moles . In other words, if the pressure exerted on the gas is doubled, this same gas is compressed, reducing its volume by half .

As the volume of the container containing the gas increases , the distance that the particles have to pass before colliding with the container walls also increases . This increased distance makes collisions less frequent , and therefore the pressure on the walls is lower than that exerted previously when the volume was lower.


Boyle’s Law was first discovered by Robert Boyle in the year 1662.  Edme Mariotte was another scientist who also had the same thought and who came to the same conclusion as Boyle, however, Mariotte did not make his work public until 1676 . This is the reason why in many books we find this law under the name of Boyle and Mariotte’s law .

Who proposed it

The Boyle-Mariotte law, or Hooch’s law as it is also known, was formulated independently by the British physicist and chemist Robert Boyle and by the French physicist and botanist Edme Matute . It is one of the laws that refers to the way in which gases relate the volume and pressure of a certain amount of gas kept at a constant temperature.

Boyle’s law statement

The statement of Boyle’s law is as follows: the pressure exerted by a physical force is inversely proportional to the volume of a gaseous mass, as long as its temperature is kept constant. Or in simpler terms we can explain it as: At a higher constant temperature , the volume of a fixed mass of gas is inversely proportional to the pressure that it exerts constant.


Boyle’s law can be expressed mathematically as follows:

P V = k


  • P is pressure
  • V is Volume
  • k is a constant that tells us when the temperature and mass are constant.

This formula can also be used to determine the change in pressure or temperature during an isothermal transformation as follows:

P1 V1 = P2 V2

This means that the product between the initial pressure and the initial volume is equal to the product of the final pressure and the final volume.


In order to test the theory of the law of Boyle, Mariotte was responsible for introducing a gas into a cylinder with piston and managed to check the different pressures that were created when the plunger down. From this experiment it was deduced that when the volume was increased , the pressure then decreased .


Boyle’s law has many applications in modern life , among them we can mention for example diving , this is because the diver must expel the air from his lungs when he ascends because it expands when the pressure decreases and if he does not do so, he could cause tissue damage.

It can be observed in all the devices that use or that work by means of pneumatic energy such as robotic arms which use pneumatic pistons , actuators , pressure regulators and pressure relief valves among other components.

The motors to gasoline , gas or diesel also use Boyle’s law in the process of combustion internal , since in a given first time enters the air to the cylinder with volume and pressure , and in a second time, decreases the volume to the increase the pressure of this.

The airbag system that cars have , which works by discharging a certain amount of air or gas from a chamber that reaches the outer bag , where the pressure decreases and the volume increases while maintaining a constant temperature. .


Boyle’s law is very important today because it is the law that we talk and explain about the behavior with the gases . It explains us, with certainty, that the pressure and volume that a gas has is inversely proportional to each other with another. So when pressure is put on the gas, its volume is reduced and the pressure increases.

Examples of Boyle’s Law

Some examples of this very important law are the following:

Calculate the volume that a gas will occupy, which is occupying a volume of 3.75 liters, at a pressure of 2 at if a pressure of 3.5 at is applied to it.

  • 1 = 3.75 l
  • 1 = 2 at
  • 2 =?
  • 2 = 3.5 at
  • Since V 1 P 1 = V 2P 2 = k

We calculate the constant of the system:

  • 1 P 1 = k = (3.75) (2) = 7.5

We solve for V 2:

  • 2 = k / P 2 = 7.5 / 3.5 = 2,143 liters

Calculate the original pressure of a gas, if when applying a pressure of 4.5 at, it occupies a volume of 1.4 liters, and its original volume was 2.2 liters.

  • 1 = 2.2 l
  • 1 =?
  • 2 = 1.4 l
  • 2 = 4.5 at

We calculate the constant of the system:

  • 2 P 2 = k = (1.4) (4.5) = 6.3

We solve for P2:

  • 1 = k / V 1 = 6.3 / 2.2 = 2.863 at

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