(Lansing State Journal, January 6, 1993)
Question submitted by Kay Jackson.
During the early winter, before lakes and streams freeze over, you may see ducks happily swimming around even though the water may be less than 35 degrees. If a person were to go into the water, they would soon feel just how cold it is. When the water touches their skin, heat begins to flow from the skin to the water. The skin's temperature begins to drop and eventually the body can not produce enough heat to make up for the heat loss to the water. Ducks can swim in this water without freezing due to their feathers. A duck has many layers of feathers and between each layer is an additional layer of air. Air is a very poor conductor of heat. This means that heat does not travel through it easily. The layers of air between a ducks feathers prevents the duck's body heat from escaping. The feathers in effect act as insulation and allow the duck to continue its happy swim.