Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?
A) Fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do.
B) Fluffing decreases the amount of heat lost by conduction when the bird makes contact with cold objects in its environment.
C) Fluffing creates a pocket of air near the bird that acts as insulation.
D) Fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat lost to the environment.

Question

Quizplus · Accepted Answer

When birds fluff their feathers, they create a pocket of air near their skin which acts as insulation. This reduces the amount of heat that is lost to the environment, helping them to stay warm in colder weather. As a result, they look larger because the extra air trapped under their feathers gives them a bulkier appearance.

Which Principle of Heat Exchange Is the Most Important Explanation