THE SCIENCE OF ICE: Ice is the frozen form of liquid water. The same substance will behave differently at various temperatures and pressures. Water (H2O) is the most familiar example. It can be a solid (ice), a liquid (water), or a gas (steam), but it is still made up of molecules of H2O, so its chemical composition remains unchanged. At sea level, water freezes at 32 degrees Fahrenheit (0 degrees Celsius) and boils at 212 degrees Fahrenheit (100 degrees Celsius), but this behavior changes at different altitudes because the atmospheric pressure changes. In fact, get the pressure low enough and water will boil at room temperature. The critical temperature/pressure point at which H2O changes from one form to another is called a phase transition.
DEICERS AND POLLUTION: Traditional airplane and runway deicers use a variety of components to prevent the formation of ice. These components are effective at preventing ice from forming, but as they wash off wings and runways, the chemicals disperse into the environment. They can be toxic, cause endocrine disruption in animals, and consume oxygen from bodies of water that would otherwise be used to support life. Including more environmentally friendly agents in the mix keeps air travel safe, without causing any new problems.
This report has also been produced thanks to a generous grant from the Camille and Henry Dreyfus Foundation, Inc.