Why Feathers are packed closely together making it difficult for air to pass through?

The statement that feathers are packed closely together making it difficult for air to pass through is not entirely accurate. Feathers are designed in a way that allows them to trap air and provide insulation for birds.

Bird feathers have a unique structure that helps them achieve insulation and flight capabilities. Each feather consists of a central shaft, called the rachis, with barbs extending on either side. These barbs are further divided into smaller barbules that hook onto each other, creating a tightly interlocking structure.

While feathers are not completely impermeable to air, they are not packed so closely that they prevent air from passing through. The interlocking barbules create small pockets of air between them, which act as insulators. These air pockets help trap body heat and prevent heat loss, allowing birds to maintain their body temperature even in cold environments.

Additionally, feathers have a natural oiliness that helps repel water and further enhances their insulating properties. This oil coating allows birds to stay afloat and dry when swimming or diving.

In conclusion, while feathers are designed to provide insulation and waterproofing, they do not completely prevent air from passing through. The interlocking structure of the barbules creates small air pockets that help trap heat and repel water while still allowing for air circulation.