The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding, pillows and sleeping bags. Orders Many - see section below. ... Two feathers A white feather Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. ... In physics, thermal conductivity, λ, is the quantity of heat transmitted, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area, when the heat transfer is dependent only on the temperature gradient thermal conductivity = heat flow rate / (distance × temperature... Look up jacket in Wiktionary, the free dictionary A jacket is an outer garment worn by both men and women, for warmth or fashion. ... Bedding refers to all types of material which make up a bed (generally excluding the mattress, box spring and bed frame, which are less portable). ... A pile of pillows A pillow is a type of bedding— a small (and usually soft) support for the head, usually used while sleeping in a bed, or for the body as used on a couch or chair. ... A sleeping bag is a protective bag for a person to sleep in, analogous to a bed and blanket. ...

Down offers excellent thermal properties, and has good lofting characteristics. This means that the down traps small pockets of air efficiently. The small pockets of air provide the thermal barrier. Down has the added property that it can be packed into a very small space.

When wet or compressed the thermal properties of the down are far diminished. In cold situations sleeping pads are used to provide insulation from the ground for those sleeping in down sleeping bags. In camping, a sleeping pad is a simple device often used in conjunction with a sleeping bag. ...

Down can be collected in a variety of ways. Birds which provide the feathers may be used for other purposes, for example to provide meat. Some birds are killed solely for their down, while some birds (particularly some geese) are periodically live-plucked of their breast feathers. Some birds line their nests with down, and such down might be harvested safely after the young leave the nest. Various meats Cold Meat Salad Meat, in its broadest modern definition, is all animal tissue intended to be used as food. ... Other uses: Goose (disambiguation) Genera Anser Branta Chen Cereopsis † see also: Swan, Duck Anatidae Goose (plural geese) is the general English name for a considerable number of birds, belonging to the family Anatidae. ...

Down feathers are thought by some to bring good luck.

External links

• Caring for down - Information on maximising the insulating properties of down.
• International Down and Feather Laboratory & Institute - A laboratory specializing in quality control of feathers and down.
• Down with down - Anti-down article from Farm Sanctuary.
• Article about down - Intriguing information about down.