"Students who believe that spontaneous processes always yield greater disorder could be somewhat surprised when shown a demonstration of supercooled liquid water at many degrees below 00 C. The students have been taught that liquid water is disorderly compared to solid ice. When a seed of ice or a speck of dust is added, crystallization of some of the liquid is immediate. Orderly solid ice has spontaneously formed from the disorderly liquid.
"Of course, thermal energy is evolved in the process of this thermodynamically metastable state changing to one that is stable. Energy is dispersed from the crystals, as they form, to the solution and thus the final temperature of the crystals of ice and liquid water are higher than originally. This, the instructor ordinarily would point out as a system-surroundings energy transfer. However, the dramatic visible result of this spontaneous process is in conflict with what the student has learned about the trend toward disorder as a test of spontaneity.
"Such a picture might not take a thousand words of interpretation from an instructor to be correctly understood by a student, but they would not be needed at all if the misleading relation of disorder with entropy had not been mentioned."
"Students who believe that spontaneous processes always yield greater disorder could be somewhat surprised when shown a demonstration of supercooled liquid water at many degrees below 00 C. The students have been taught that liquid water is disorderly compared to solid ice. When a seed of ice or a speck of dust is added, crystallization of some of the liquid is immediate. Orderly solid ice has spontaneously formed from the disorderly liquid.
"Of course, thermal energy is evolved in the process of this thermodynamically metastable state changing to one that is stable. Energy is dispersed from the crystals, as they form, to the solution and thus the final temperature of the crystals of ice and liquid water are higher than originally. This, the instructor ordinarily would point out as a system-surroundings energy transfer. However, the dramatic visible result of this spontaneous process is in conflict with what the student has learned about the trend toward disorder as a test of spontaneity.
"Such a picture might not take a thousand words of interpretation from an instructor to be correctly understood by a student, but they would not be needed at all if the misleading relation of disorder with entropy had not been mentioned."
http://entropysite.oxy.edu/cracked_crutch.html