What is Liquid?
[[File:Drinking water.jpg|thumb|Water is a liquid]] A '''liquid''' is a form of [[matter]]. It is settled between [[solid]] and [[gas]]. Liquid has an almost-fixed [[volume]], but no set shape.<ref>{{Cite web |url= http://www.chemicool.com/definition/liquid.html |title=Definition of liquid - Chemistry Dictionary |work=chemicool.com |accessdate=22 March 2010 }}</ref> Every small force makes a liquid change its shape by [[Flux|flowing]]. Because of that, gravity makes liquids always take the [[shape]] of the [[container]]. The [[molecules]] that make up the liquid can freely move among themselves.<ref>{{Cite web |url= http://www.brainyquote.com/words/li/liquid185243.html |title=Definition of Liquid |work=brainyquote.com |accessdate=22 March 2010 }}</ref> Fluids that flow slowly have a high [[viscosity]].<ref>{{Cite web |url=http://www.spacegrant.hawaii.edu/class_acts/ViscosityTe.html |title=Teacher Page: Viscosity |work=spacegrant.hawaii.edu |accessdate=23 March 2010 |archive-date=2 February 2010 |archive-url=https://web.archive.org/web/20100202014944/http://www.spacegrant.hawaii.edu/class_acts/ViscosityTe.html |url-status=dead }}</ref> Some fluids like [[tar]] have such a high viscosity that they may seem [[solid]].<ref>{{Cite web |url= http://www.physlink.com/Education/AskExperts/ae15.cfm?CFID=26960032&CFTOKEN=354acc2daa800b20-8D0433E3-15C5-EE01-B9F62DD567C6E026 |title=Can you compress a liquid (water)? |work=physlink.com |accessdate=23 March 2010 }}</ref> It is difficult (near impossible) to compress a liquid. If a liquid is cooled down until it is colder than a certain temperature, it will become a [[solid]]. This temperature is called the [[melting point]] or freezing point and is different for every different type of liquid. If a liquid is heated up it becomes a [[gas]]. The temperature this happens at is called the [[boiling point]]. Examples of liquid are [[water]], [[oil]]s, [[tar]] and [[blood]]. In a liquid, the liquid on the top presses down on the liquid underneath, so at