Why Statistical Mechanics Understand predict the physical properties of macroscopic systems from the properties of their constituents Deterministic approach ma=F need of 6N coordinates at t r: and u but typically n= moles (1023)! “ Ensemble” rather than microscopic detail and its surroundings microcanonical, canonical, grand canonicalWhy Statistical Mechanics? Understand & predict the physical properties of macroscopic systems from the properties of their constituents Deterministic approach - n e e d o f 6N coordinates at t 0: ri and vi - b u t t y p i c a l l y N ≡ moles (1023) ! “Ensemble” rather than microscopic detail … and its surroundings ¾microcanonical, canonical, grand canonical