The laws that establish how things work on planet Earth are there, affecting us all the time, even though we sometimes lose sight of them or, worse still, have no idea about them. Therefore, in this article, we will see what the Zero Law of Thermodynamics means and where it applies.
This law, which is also known as the “law of thermal equilibrium”, was first postulated by Maxwel and later adopted by Fowler, arguing that, when two systems with their own temperatures , different from each other, come into contact, both will exchange heat until those temperatures equalize.
Of course, although the human being as a species could not explain the operation of these laws since the beginning of time, it is clear that the concepts of “cold” and “hot” accompany our species since its first appearances on the planet.
Leonardo Da Vinci and Galileo already mentioned these notions, and they were very clear that hot bodies have the tendency to transfer their energy to colder bodies, a flow known as “heat or calorific energy” within the jargon.
The process will remain unchanged until the body that in an initial instance had the lowest temperature , has reached the one that now has the originally warmer body.
With this adopted, later arises the development of the theory of thermal equilibrium, that state in which both systems acquire that temperature in common. Why is that idea so important? Because it is the one that definitely explained that temperature is a thermodynamic property, discarding, as was believed until then, that it was a property of each substance.
Application of the Zero Law of Thermodynamics
The application of the zero law is an infallible method to measure the temperature of various systems, taking advantage of this thermodynamic property , normally calculable thanks to a thermometer made of glass, which indicates the result by the same thermal expansion of this material.
And although in certain cases only the touch of our hands may be enough, in scientific or industrial uses the exact numerical value must be obtained, which requires the thermometer: a versatile product that quantifies the temperature of a refrigerator as well as an oven. .
NASA even has extremely precise thermometers to know the level of heat that a spacecraft reaches in key instances, such as when leaving or entering the atmosphere.
