Simple Answer…
Because water starts to expand when you chill it to within a certain temperature range. If you want to know why this strange fact is true, keep reading.
More detailed answer…
Through our early years, we all learned at one point or another that heat makes things expand and cooling things generally makes them contract or shrink. As we all grew up, most of our practical experiences verified and validated this seemingly unassailable law of nature. Whenever a body part became swollen as a result of an injury or a bug bite, applying a bag of ice to the affected area would consistently reduce the swelling… a form of contraction. If ever we placed an empty plastic bottle in a refrigerator or freezer, it would shrink and crumple in on itself… also a form of contraction. We have all also witnessed the opposite end of this assertion every time we’ve watched the evaporation that occurs off of a pot of boiling soup. As the soup is heated, some of it expands as it transforms into gas and seemingly disappears before our very eyes. This phenomenon of heat induced expansion as well as contraction under conditions of extreme cold generally holds true in the physical world. As with most rules of nature however, there is an exception to this general law. To put it plainly, not everything contracts when it is cooled. As a matter of fact, one of the most plentifully present fluids and primary source of life on our planet disobeys this law within a particular temperature range. That’s right… water actually expands when it is cooled to a certain temperature. This rather strange behavior of water is technically referred to as the “anomalous expansion of water” (anomalous is just a fancy word for abnormal or strange). To understand this phenomenon completely, we’ll have to start by dipping our “intellectual toes” into the vast labyrinths of physics and chemistry. Continue reading Why do plastic water bottles burst if left in a freezer for too long?
