A lot of the less maths-y definitions of entropy talk about disorder and how disordered a system is. I'm given to understand that entropy is a measure of energy over temperate. Could someone clear up these misconceptions? I don't understand why 'disorder' is used. Isn't that subjective? Second question. I don't understand why entropy has to increase or stay constant in a closed system over time. Surely say, in a room where air molecules are bouncing around, they would at some point move to a more 'ordered' state?