上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY 10.2 Microstates and Macrostates In order to compute the macroseopic average of a property .The property of each microstate .Which microstates the system can be in .The probability that the system will be in a given microstate The macroscopic pressure equals to the time average of the Macrostate: instantaneous pressure stating the total number of particles in each box yields Macroscopic pressure Microstate: each way of realizing a given macro distribution Instantaneous pressure Each macrostate may be realized by a number of microstates Time> Figure 10.2 Instantaneous gas pressure as a function of time.(The magnitude of the variation of instantaneous gas pressure is exag- gerated for emphasis.)10.2 Microstates and Macrostates The macroscopic pressure equals to the time average of the instantaneous pressure