Thermodynamics

A macrostate and a microstate are two very different ways of looking at a system. (Admittedly, a macrostate always has to involve an amount of matter large enough for us to measure its volume or pressure or temperature, i.e. in “bulk”.

• A macrostate and a microstate are two very different ways of looking at a system. (Admittedly, a macrostate always has to involve an amount of matter large enough for us to measure its volume or pressure or temperature, i.e. in “bulk”.
• But in thermodynamics, a microstate isn't just about a smaller amount of matter', it is a detailed look at the energy that molecules or other particles have.) A microstate is one of the huge number of different accessible arrangements of the molecules' motional energy for a particular macrostate.
• A macrostate is the thermodynamic state of any system that is exactly characterized by measurement of the system's properties such as p, V, T, H and number of moles of each constituent. Thus, a macrostate does not change over time if its observable properties do not change.

In contrast, a microstate for a system is all about time and the energy of the molecules in that system. In a system its energy is constantly being redistributed among its particles. In liquids and gases, the particles themselves are constantly redistributing in location as well as changing in the quanta (the individual amount of energy that each molecule has) due to their incessantly colliding, bouncing off each other with (usually) a different amount of energy for each molecule after the collision..

• In contrast, a microstate for a system is all about time and the energy of the molecules in that system. In a system its energy is constantly being redistributed among its particles. In liquids and gases, the particles themselves are constantly redistributing in location as well as changing in the quanta (the individual amount of energy that each molecule has) due to their incessantly colliding, bouncing off each other with (usually) a different amount of energy for each molecule after the collision..
• Each specific way, each arrangement of the energy of each molecule in the whole system at one instant is called a microstate.