Student News

Molecule of the Week – Water (part 2)

Hills, Ivory – December 1, 2011

Solid water is called ice. Ice is weird stuff!

Many liquids will become solids if you lower the temperature (freeze them). For example, ethanol becomes a solid at the lovely temperature of -114 °C (-173 °F). Please try to imagine how unpleasant it would be to watch a hockey game if you had to sit in an arena cooled enough to freeze ethanol. Brrrrrr, I’m glad water freezes at 0°C (32°F)! 

Another interesting fact is that as you cool most liquids their density increases as they freeze. Liquid ethanol at room temperature has a density of 0.76 g/mL and when frozen has a density of 0.81 g/mL (The solid is more dense than the liquid); however, liquid water has a density of approximately 1.0 g/mL and ice has a density of 0.92 g/mL (The solid is less dense than the liquid). This is confusing – what does it all mean?

It means that frozen ethanol does not float in liquid ethanol. However, frozen water (ICE!) does float in liquid water.  That is weird stuff!