An essay describing why water/gallium expand when frozen.

Essay by cheatermikeHigh School, 12th gradeA+, December 2004

download word file, 2 pages 5.0

Why Stuff Expands

There is a reasonable explanation to the question of why water expands both when heated and cooled. Not only is the explanation reasonable, but the effects of this odd property have their own advantages and disadvantages as well.

This process of expansion by cooling starts when the water temperature nears 4° C. The hydrogen atoms begin to line up into neat rows of six molecules, but the water retains the same density, except for the slight drop that is common with most matter just before solidification. Once the water temperature has dropped to 0° C, the rows of molecules connect at the ends to form an open-ended hexagon. Because of the empty spaces into the middle of these hexagons, the ice takes up more space than the same amount of liquid water. The net result is approximately 9% more volume.

The disadvantages of this peculiar property are many.

For example, if a container holding water is made of something rigid, like metal or glass, will most likely break or crack. This is why pipes can be broken during the winter. If some liquid water gets into a small crack in asphalt, concrete, or brick, the crack will be pushed apart and opened wider when freezing occurs.

The advantages of water expanding are also many and important to life itself. If the ice were to get denser than its liquid form, then ice would sink to the bottom of a pond, and the fish would not be properly insulated. Not only would the fish not be insulated, but they would freeze solid along with the pond from the bottom up. Ice-skating is another thing that would be impossible for this very same reason.

An interesting phenomena that has much to do with the expansion of water when it...