A few students have asked, “What do you mean by the term liquid?” The Chemistry I Density Bottle Project requires at least four different liquid layers. I think this leads us to exploring the definition and discussing the properties of this state of matter.
According to dictionary.com and the American Hertiage Dictonary, a liquid is the state of matter in which a substance exhibits a characteristic readiness to flow, little or no tendency to disperse, and relatively high incompressibility. Therefore, in order to qualify as a liquid for this project, the substance must flow, not evaporate into vapor readily and be incompressible. (this means you can’t smoosh it into a smaller space)
Some have asked, “Can I use water with things mixed in to change the density?” You can try this yourself, but think this out. If you mix salt with water and if you mix sugar with water, when you pour this into the same bottle, since they are both water, won’ they mix? Think about substances that don’t mix with water. Maybe you want to try these. Maybe you want to check out some properties of water according to the US Geological Survey’s site on water. This might help you decide whether or not to even use water.