Do liquids freeze at the same temperature? Why doesn't oil freeze?
Almost everything has a unique temperature at which it will freeze/melt and condense/boil. The temperature that it melts at is the same that it freezes at. Likewise with condensing and boiling. The only difference between those two sets of points is whether you are adding heat (temperature rising) or taking heat away (temperature falling). What confuses people is that we call 32 degrees F freezing, but that is only for water.
You would be surprised how many peoples minds are blown by liquids boiling at temperatures that are "cold" despite the fact that it happens around them all the time (that's how air conditioning works). Oil DOES freeze! Just ask the people who live in International Falls, Minnesota! Most oils have wider liquid temperature ranges than water, which is typically used for reference.
Brian Kross, Chief Detector Engineer (Other answers by Brian Kross)