Temperature Effects on Density
The easiest way to understand the PvT relation is to generate it by a thought The pressure will remain constant and the temperature of the water will begin to. The Gas Laws: Pressure Volume Temperature Relationships . pressures are useful when gases are collected by bubbling through water (displacement). In a closed system where volume is held constant, there is a direct relationship between Pressure and Temperature. In a direct relationship, one variable follows .
Relationships among Pressure, Temperature, Volume, and Amount
Most materials have a lower density of the liquid than the solid but this isn't always true. Water has a higher density in the liquid state than the solid, so ice cubes float. Within a particular phase, how does the density depend on temperature?
Remember that temperature is related to the average kinetic energy of the atoms or molecules within the substance.
PRESSURE AND TEMPERATURE RELATIONSHIP
Pure Water The density of liquid water is approximately 1. Let's look at the density of water at 25 deg C and compare that to a higher temperature, 80 deg C.
The density decreases from 0. This makes sense because, as heat is added to the liquid water, there is greater kinetic energy of the molecules and there are also more vibrations of the water molecules. Together these mean that each H2O unit in liquid water takes up more space as the temperature increases. We see the same trend in going from liquid water at 25 deg C 0. Density increase as the temperature decreases.
Below 4 deg C, however, the density decreases again. How can we explain this? Remember that liquid water and solid water have the same network of bonds. Liquid water at 25 deg is so rapidly breaking bonds between H2O units and reforming them that extra water molecules get trapped inside the water lattice. Conceptually, I think, there must be a "slush-zone" slightly above where the water is in equilibrium where the water is more viscous.
Pressure, temperature, and volume relation in liquids
I'm thinking of this in the same terms of the transition zones between magma and mantle. My mind wandered a bit after this, beyond the local lakes and the spring thaw to the constant cold polar regions. If my idea of a "slush zone" is valid, then, while the water itself would be ever changing the zone's presence would be constant.
Does this increased viscosity make for a micro-environment of sorts? Randy- I made a guess as to what question you were following up.
You can write back if you meant another thread. It turns out that there really isn't a liquid-solid continuum.
There's an abrupt difference, in density, hardness, electrical properties, etc. The change between liquid and ice is thus called a "first-order phase transition".
Slush is just a mixture of ice crystals in liquid water, not a real in-between state. If you leave it at some temperature for long enough, it will all turn to either ice or liquid, depending on the exact temperature.
Water's Unexpected Properties
Nevertheless, you're right that the viscosity of water does increase quite a bit as it gets colder. That's pretty typical for most liquids even if they aren't near a phase transition. They turn solid-seeming without ever going through a phase transition to form actual crystals. This frozen state is called a "glass". I don't know much about magma, but it's possible that it has one of these glass transitions, without a sharp phase transition from the very viscous liquid to the hard glass, like obsidian.