Avogadro’s Law Examples in Real Life

Avogadro's Law

Avogadro’s law tells about the relationship between the volume of a gas and the number of molecules possessed by it. It was formulated by an Italian scientist Amedeo Avogadro in the year 1811. During a series of experiments conducted by him, he observed that an equal volume of gases contains an equal number of particles. In other words, Avogadro’s law states that for an ideal gas, the volume of the gas is directly proportional to the number of moles possessed by it provided a constant temperature and pressure is maintained. This means that with an increase in volume, the number of moles will increase. Similarly, with a decrease in volume, the number of moles will also decrease. It is also known as Avogadro’s principle or Avogadro’s hypothesis. It is only applicable to ideal gases and gives an approximate result for the real gases. The gases with light molecules such as helium, hydrogen, etc. obey Avogadro’s law in a better manner as compared to the gases with heavy molecules.


1. Breathing

Human lungs demonstrate Avogadro’s law in the best possible way. When we inhale, the lungs expand because they get filled with air. Similarly while exhaling, the lungs let the air out and shrink in size. The change in volume can be clearly observed, which is proportional to the amount or the number of molecules of air contained by the lungs.


2. Inflating Balloon

To inflate a balloon it is required to be stuffed up with air molecules that are blown inside it either through the mouth or with the help of a pump. If you decrease the amount of air contained by the balloon, a significant decrease in the volume or the size of the balloon can be observed. Hence, Avogadro’s law can be observed in action.

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3. Filling Tyres with Air

Flat tyres do not contain a sufficient amount of air molecules in them, which is why they lack proper shape. When the flat tyre of a vehicle is attached to an air pump, the air molecules get pressed into it. The number of particles of air present in the flat tyre increase; therefore, the volume increases accordingly. This helps the tyre to regain its original shape. Hence, the inflation of flat tyres is a clear demonstration of Avogadro’s law in everyday life.

Filling Tyres with Air

4. Pumping Air in a Ball

A sports ball contains a bladder and a rigid outer covering. When the ball gets deflated the bladder gets deprived of air and loses its shape. Thereby, causing the ball to lose the ability to bounce. The volume of the air present in the bladder can be increased by forcefully pressing air into it through an air pump. The change in volume of air is proportionate to the change in the number of air molecules possessed by it. Hence, pumping air in a sports ball is an explicit illustration of Avogadro’s law in real life.

Pumping Air in a Ball

5. Bicycle Pump Action 

The action of a bicycle pump makes use of Avogadro’s law. The pump extracts the air from the environment and pushes it inside the structure of the deflated object. The increase in the number of gas molecules in the object correspondingly changes its shape and helps it to expand. This proportionality between the number of molecules of the air and the volume is nothing but Avogadro’s law.

Bicycle Pump Action

6. Pool Tube

The pool tube, in deflated form, is easily portable in nature. The absence or scarcity of the number of molecules in the tube reduces the volume and makes it compact. During inflation, when the tube is filled with air, the number of air molecules inside it increases. Thereby, increasing the volume and size of the pool tube. Hence, Avogadro’s law can be implemented to inflate or deflate the pool tube as per the requirement.

Pool Tube

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