Charles law Calculator

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Have you ever developed a fascination towards ‘chemistry’ and do you remember a plethora of laws in the subject? Well, for me exceptions were the craziest part. I still don’t understand how we have laws and then the exceptions. However, the subject has so much to offer and contribute to the existence of us and things around us.
The laws have always been an easy way out for me. There are so many things to keep in mind mathematically that at times you fail at it miserably. Thanks to all the brilliant experts and scientists who discovered laws and made various concepts easy.
Hear me out! Life is so much better with these laws to trust me. They help us out so much in daily life. You just may not realize it. Everything that is around us has some kind or other chemistry involved in them and these laws are truly useful there. You just need to look close enough. For all the chemistry loving nerds out there, laws always get the best of you too.

Today we will discuss one such useful law- Charles’s Law. You can have your doubts cleared by going through the insights of this law below.

Discovery of Charles’s Law

Ok, guys, this one is interesting, so the story goes that Jacques Charles invented manned-balloon flight, and that balloon used hydrogen gas to inflate the balloon. Although the hydrogen gas was produced there it by the exothermic reaction, and we all know what exothermic reaction is-it means the hydrogen gas produced was hot. So after some time of filling the balloon with hot hydrogen gas, Charles noticed that the volume of gas had increased and hence he inflated the balloon more. But little do the story he could not give any further proof to this theory and hence it was not coined the Charles law then. Later in the coming years, Gay Lussac while researching got the valid proof for the theory of Jacques Charles. So in honor of him, Gay Lussac coined the term Charles’s law.

Hence in many books and published papers, the law is also known as Lussac-Charles law. The discovery was done in the year 1801.

Charles’s Law

Charles’s law gives us the relationship between the temperature of the gas and the volume of the gas. To put into simple words the law explained how the gases tend to expand if the temperature is increased.

So What Charles’s law states? It states that
‘When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion’

In other words, there is a direct relationship between the temperature of the gas and the volume of the gas. So as the temperature increases the volume of the gas also increases conversely if the temperature decreases then the volume of the gas also decreases. The conditions for this law to act upon are that the pressure and the amount of the gas should remain constant.

Charles law Equation

All the laws are always converted to their mathematical form so that the calculations are simplified and easy to grasp.

The law states that change in temperature (T) of the gases will result in a change of volume (V) of the gas keeping the pressure and amount of gas fixed.

Let’s look at the mathematical relationship-

V/T = k
V = KT

Here k is the constant of proportionality
V = volume of the gas
T = temperature of the gas in Kelvin.

Graph of Charles’s law

The graph is plotted between the temperature and volume of the gas. The graph comes out to be a straight line with a positive slope. The volume (V) is plotted on the Y-axis, while the temperature (T) is plotted on X-axis.

Derivation and Calculation

As per the statement of Charles law, the volume of the gas and temperature of the gas are directly proportional. So that means

V/T = k
So we may take into consideration,
V1/T1 = k  ———————————-1
V2/T2 = k  ———————————-2
V1 = initial volume of gas
T1 = initial temperature of the gas
V2 = final volume of gas
T2 = final temperature of the gas
V1/T1 = V2/T2
which gives us Charles law

Application of Charles law in daily life

Hot air Balloon

Classic example of Charles law can be found in any textbooks. At the beginning of the article, we saw how Charles himself made a hydrogen manned balloon. So the hot air balloon consists of the basket to hold people, along with the ignition system. The ignition system is used to heat the air in the balloon above. The hot air expands as per Charles’s law. With the increase in temperature of the air the volume of air also increases and the density decreases. This makes the air inside lighter than the outside atmospheric air and hence the balloon flies.

Human lungs

One of the most important organs in the body, the lungs helps us to breathe. In winters when the temperature is low, we breathe in the cold air, as a result, the volume also decreases, this means that we breathe in lesser air as compared to the rest of the seasons. So if you have curiosity as to why we feel breathless in winters or cold environments, this is because the of Charles’s law. See chemistry is all around us.

Ping pong balls

We have seen and played with many ping pong balls, mostly in table tennis. The thing with ping pong balls is that from time to time they dent up very easily and are further useless to play. But don’t worry you guys, Jacques Charles to the rescue. A common method to fix this dent is by immersing the ball in warm water. The warm water helps the air inside the ball to expand and the dent is gone. Now it’s all ready to play with again. All thanks to Jacques Charles.


Many of us might have noticed that the tyre of cars usually is more inflated than they normally are. And in winter they are deflated than normal. This happens due to cold and hot temperatures respectfully. This is why it is always good to keep the tyre pressure in check.