The Teenager's Bedroom

The second law of thermodynamics puts into mathematics the commonplace observation that heat flows from hot things to cold ones, and not the other way around. This mathematical treatment, though, has many consequences. One of the best known is that any system will become more disordered as time passes. That applies as much to two gases mixing as it does to a teenager's bedroom.

"Wy does time pass?: The moving finger writes" The Economist, Volume 426 Number 8954, September 5th-11th 2015, Accessed on September 5, 2015, http://www.economist.com/news/science-brief/21663184-our-fifth-brief-scientific-mysteries-we-ask-why-travelling-through-time-unlike