Phenomenological Thermodynamics

I did my Thermo course already. Why do I need your Stat Thermo?

phe-nomé-nólo-gy, n ... 2. Scientific description of actual phenomena with avoidance of full interpretation, explanation, and evaluation
Webster's Collegiate Dictionary , 5th edition.

Phenomenological Thermodynamics:

• Developed before atomistics
• We know that if A is colder than B, heat will flow from B to A.
• We know that there is such thing as energy that conserves
• We know that there is such thing as entropy that increases

Can we build a steam engine on this background? Yes! We can even build a refrigerator!

Problems with Phenomenological Thermodynamics:

• We know how , but do not know why .
  • Why do liquids evaporate at heating but never at cooling?
  • Why do all gases behave similarly?
  • Can the temperature be negative?
  • What is this thing entropy, by the way?
• We need all the constants and parameters from the experiments (that is what phenomenology means, by the way). We have no clue about their possible values!
• We have no clue what thermodynamic properties will the systems, build with given molecules have--not very good for materials science ! We can build a refrigerator, but we cannot design a proper fluid for it--we can only choose from the ones we know!