Real-Life Examples of Law of Conservation of Mass

Law of Conservation of Mass

One thing that all chemists should be familiar with is the law of conservation of mass.  Do you know clearly what it is and its examples in real life? If the answer is No, then read on the article to find answers to these questions.

What is the Law of Conservation of mass?

The law of conservation of mass states that,

In a closed system, the matter can neither be created nor destroyed  – it can only be transformed from one form to another.

This law is particularly important when combining different materials and testing the reactions between them. When a substance undergoes a chemical reaction, one might assume that some or all of the matter present is disappearing, but in actuality, it is simply changing form.

History Behind the Law

Though the ancient Greeks laid the scientific groundwork necessary for the discovery of the law of conservation of mass, the French chemist Antoine Lavoisier is credited as its discoverer. Lavoisier through experimentation discovered that mass does not change in a chemical reaction, which led to the discovery that mass remains constant in a chemical reaction. Lavoisier’s experiments marked the first time someone clearly tested this idea of the conservation of matter by measuring the masses of materials both before and after they underwent a chemical reaction.

Real-Life Examples


Imagine that you have gathered sticks and set it on fire to toast marshmallows.  After toasting a couple of marshmallows, you realize that the sticks have completely burned down. Now you are left with just ashes and smoke. Your initial instinct might be to assume that the campfire’s mass has vanished. But it actually hasn’t – it is simply transformed.

In this case, as the sticks burned they combined with oxygen in the air to turn to ash, carbon dioxide and water vapour. As a result, if we measured the total mass of the wooden sticks and the oxygen before setting the sticks on fire, we’d discover that this mass is equal to the mass of the ashes, carbon dioxide, and water vapour combined.


A burning candle is an example of the law of conservation of energy. When the candle is completely burned down, you see far less wax in the candle than when you lit it. This implies that some of the wax has been transformed into gases (carbon dioxide and water vapour.)

Knowing scientific laws such as this one is important for the study of science.  To study and revise your understanding of various laws and concepts such as RMS value subscribe to BYJU’S – The Learning App.

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