Transcript: The laws of microscopic physics are invariant with respect to time which is to say that microscopic interactions can move backwards or forwards equally well. The laws of physics really say nothing about the arrow of time, and yet when a movie is run backwards it’s obviously silly and...

Transcript: Disorder or entropy tends to increase because disordered states are usually the most common outcome in an experiment or any situation. Take the artificial but simple example of four coins, each of which has two outcomes when it’s tossed and is independent of the other. There are two...

Transcript: The third law of thermodynamics states that it’s impossible to remove all the heat from a physical system. At the temperature absolute zero there is no heat, and there is no atomic motion. So there would be no friction, and perfect machines with perpetual motion would be possible. ...