# Who discovered the third law of thermodynamics? (And when?)

The third law of thermodynamics was discovered by German chemist Walther Hermann Nernst during the year 1906 to 1912.

Explanation:

Let me tell you some history behind the discovery of Third law of thermodynamics.

When German chemist Walther Hermann Nernst studied about the second law of thermodynamics, his mind was completely disturbed.

He studied that the entropy of the universe keeps on increasing for all the process occurring on it’s own.

He thought that, what should be done so that the entropy of the universe will not increase and it will remain constant?

Then he studied everything about entropy. After a lot of studying and research work, he discovered the third law of thermodynamics.

In 1912, he gave the postulate:

“It is impossible for any procedure to lead to the isotherm T = 0 in a finite number of steps.” (Source: Google books)

Later in 1923, the alternative version of third law was given by Gilbert Lewis and Merle Randall which states that for the perfectly crystalline substance, the change in entropy ∆S as well as entropy of the substance S, both will reach to 0 at absolute zero temperature (i.e 0 K).

If the substance is not pure crystalline, then there may be some residual entropy present in it.

Finally as the statistical mechanics evolved, this law became the derived law instead of fundamental law and today we know 3rd law of thermodynamics as mentioned below.

“The value of entropy of a completely pure crystalline substance is zero at absolute zero temperature”

I hope now you have come to know some basic history behind the discovery of the third law of thermodynamics.

For more detailed information on Third law of thermodynamics, check the ultimate guide on Third law of thermodynamics.

(This guide has all the important knowledge about Third law of thermodynamics along with examples and lots more. You will love this guide for sure.)

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