Here is a quote from a chemistry textbook "In nature, objects tend to change in such a way that their total energy is minimised. The lower their energy, the more stable they are, since they have less capacity to do things." I assume they are talking about total energy=kinetic + potential energy My question is, is this a law of nature? If so what is it called? Or is it derived from a law? If so how? What law is it derived from? It goes on saying "A liquid dropped to a surface will spread over the surface if by doing so it creates a surface of lower energy." How does the liquid know it will create a surface of lower energy? Or does it just do its thing (i.e when it reaches a new surface it samples the atoms to see if it can bind with them. If they can than they do and we say before they bind they have a higher total energy than afterwards when they are collapsed on the surface hence they have lowered their energy) and in the end we find what they have done is lower their total energy.