What is Charles Law in Simple Words ?

Charle’s Law in Simple Words

Jacques Charles, in 1662, gave the law known as Charle’s law. It relates the volume and absolute temperature of ideal gases at constant pressure and mass.

Charle’s Law Statement

According to Charle’s law “For a fixed mass of a gas, the volume is directly proportional to absolute temperature at constant pressure.”

V     ∝   T     …………….. (1)

This shows that when absolute temperature increases, volume increases to the same fold and vice versa.

V     =   KcT


V / T   =   Kc   ……………. (2)

Charles law can also be stated as:

“For a fixed mass of a gas, the ratio of volume and the absolute temperature remains constant at constant pressure.”

It means volume changes with a change in absolute temperature but the ratio V/T remains the same.

Let the volume of a gas is V1 at absolute temperature T1. Then

    V1/T1   =   Kc        ……………… (3)

If pressure changes to P2 then the volume will change to V2 such that the ratio remains the same

  V2/T2   =   Kc       ……………… (4)

Comparing equations (3) and (4), we can write

         V1   / T     =         V2 / T2       ……………… (5)                                                                 

Charle’s law Experiment

The law can be verified by using the apparatus as shown in the figure. A glass tube closed at one end is taken in which some mercury is poured. The air present in the tube will be trapped at the close end and mercury will act as a frictionless piston. The tube will be placed in the thermostat.

Charle’s law Experiment

such that

         T1 < T2 < T3

By increasing the temperature it can be seen that volume increases. Thus the law is verified.

 such that  

       T1 < T2 < T3

By increasing the temperature it can be seen that volume increases. Thus the law is verified.

Law is further verified by plotting a graph for temperature versus volume it gives a straight line which verifies the law.

Charle’s law

Charle’s law Graph

Charle’s law graph

J.L Gay Lussac also showed a similar relationship between Celsius temperature and volume. It states

“For each one-degree centigrade rise or fall in temperature, the increase or decrease in volume is 1/273 of the volume of gas at 0oC.” 

Let the volume of a gas at 0oC = Vo

Charle’s law Explanation

This temperature at which the volume of a gas becomes hypothetically zero is called absolute zero (i.e. zero of absolute or Kelvin scale).

It shows that Charle’s law and Gay Lussac’s laws are one and the same.

Charle’s Law Explained on the basis of KMT:

Consider a cylinder fitted with a freely movable piston. Let the cylinder contains ‘n’ number of molecules at temperature ‘T’, volume is ‘V’ and pressure exerted by molecules is ‘P’.

Charle’s law Experiment

Further, consider that temperature is raised to double. As temperature became double so av. K.E also becomes double and in turn, collisions also become double. Thus piston will be pushed up to double volume so that internal and external pressure again becomes equal. It means when the temperature increases twice, the volume also increases twice. i.e.

  V    ∝     T

And this is the statement of Charle’s law.

Charle’s Law Example

Here are numerous instances in which Charles’ Law is applicable:

If you take a basketball outside on a cold day, the ball will contract somewhat as the temperature drops. This also applies to any inflated object, which is why it’s a good idea to check the tyre pressure of your vehicle when the temperature decreases.

Charles law applied to deodorant

This is due to Charles’s Law. According to Charles law Definition, “during high temperatures, the gas molecules within the deodorant container expand, which might cause the bottle to rupture.”

Related Post -> Boyle’s Law

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Frequently Asked Questions-FAQs

What is Charles law state?

Charles’ law is a physics principle that states the volume of a gas equals a constant value multiplied by its temperature as measured on the Kelvin scale (zero Kelvin corresponds to -273.15 degrees Celsius).

What examples demonstrate Charles Law?

Undriven automobiles’ tyres collapse during frigid winter days and inflate during hot summer days. This strange behaviour is the result of Charles’s law. Due to winter’s low temperatures, the air within a tyre cools and contracts. On hot days, the air expands as the temperature rises.

What are some applications of Charle’s law in daily life?

The practical implementation of Charles Law can also be observed in our kitchen. Yeast is utilised for fermentation in order to make bread and cakes light and airy. Yeast creates carbon dioxide gas. When bread and cakes are baked at high temperatures, carbon dioxide gas expands as the temperature rises.

Can Charles law be experimentally proven?

Several laboratory tests exist to verify Charles’ law. Some are contemporary, while others are conventional. Regardless of the method employed, the purpose and outcome of an experiment remain unchanged. Charles’s law establishes a relationship between volume and temperature at constant pressure.

Also, Read!!

Bohr’s Atomic Model

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