Stock Photo - Communicating vessels: If we add water to any vessel, there is a movement of water (a flow of matter) until the water has levelled out. There is also a flow of potential energy until each milligram of water on the surface has the same potential energy as any milligram on the surface of another tube. An increase or decrease of water in any tube affects the water in all other tubes according to well-known laws of physics.

Stock Photo: Communicating vessels: If we add water to any vessel, there is a movement of water (a flow of matter) until the water has levelled out.