Water is a fluid, not a liquid. https://en.m.wikipedia.org/wiki/Liquid Liquid is considered one of the four fundamental [i]STATES[/i] of matter. The others are soild, gas, plasma Water being liquid is considered the state for which the water is in, a liquid state. https://physics.aps.org/articles/v2/88 http://askville.amazon.com/unit-measurement-fluidity-liquid/AnswerViewer.do?requestId=13265877 The second link shows the measurement for the fluidity of a liquid. Why would they need fluidity to measure a liquid? Because liquid is the state that it is in