Why Do Water Bottles Shrink?
Other People Are Reading
-
Molecules Shrink When Cold
-
During periods of extreme cold, like when a water bottle remains in a car through a cold winter night or is stashed in a freezer for a few hours, the molecules in the water and air actually shrink. According to The Naked Scientists, the components of air and water get larger when they heat up and get smaller when cold. Because of this concept, air and water inside a water bottle shrink when the bottle is exposed to cold temperatures for a prolonged period of time.
The Bottle Shrinks With Its Contents
-
When a water bottle remains in a cold environment long enough for its contents to shrink, the bottle may shrink along with the air and water inside. Its contents consist of some ratio of air and water. In addition, the bottle's cap seals the contents inside, creating a veritable vacuum. When the water and air shrink inside the bottle, and the cap prevents more air from rushing in to fill the void, the bottle may either shrink along with its contents due to the cold weather, or the vacuum created inside the bottle may pull the bottle's sides inward and cause it to collapse in on itself.
-
Hot Water Also Shrinks Bottles
-
While cold weather can shrink both water bottles and their contents, hot water can also exhibit the same---and sometimes more pronounced---effect. Because many water bottle users choose to reuse the bottles to save money and protect the environment, they may attempt to clean the bottles out using hot water (with or without soap); others may attempt to run the bottles through dishwashers that use liberal amounts of heat to clean and sterilize dirty dishes. During intense cleaning cycles, users may notice that the water bottles shrink after exposure to very high temperatures. According to an article posted by the United States Department of Energy, all solid materials naturally expand and contract. When polymers like plastic heat up, though, the long chains of materials bonding carbon atoms contract, pulling the entire material inward and creating a shrinking effect. If a user heats only part of a water bottle, that portion may shrink while surrounding areas remain at their original size, creating a puckered area inconsistent with the bottle's original shape. In addition, some plastic polymers commonly found in water bottles may craze slightly when the polymer bonds contract, replacing the clear plastic with a white, milky translucent material.
-
