A large kettle of hot soup cools down very slowly as compared

May 9, 2013

Nature up close

We had been warmed canada goose uk black friday by walking (actually, slogging) through the snow, but we were still really cold in spite of our thick coats and gloves. canada goose clearance How were these tiny birds, canada goose factory sale the smallest bird in the northern woods weighing in at all of one fifth of an ounce the canada goose black friday sale weight of a quarter! able to survive well below buy canada goose jacket freezing temperatures?

The further north an animal lives, canada goose generally the bigger it is. Temperature wise, that makes sense. A large kettle of hot soup cools down very slowly as compared to a piece of toast. But here was a group of tiny birds doing just fine. How?

An English major buy canada goose jacket cheap might quote Emily Dickinson and say “Hope is the thing with feathers.” A biology major canada goose uk shop would (quite unpoetically) say, “Feathers are unbelievably well adapted by millions of years of evolution to allow Canada Goose Outlet birds canada goose coats to fly and stay warm.”

Feathers truly are canada goose store some of canada goose uk outlet the most amazing structures in the natural world; they are extremely lightweight (which is helpful if you fly); replaceable canada goose outlet uk (when one is lost a new one grows in to replace it); they are fantastic insulators; and they provide superb waterproofing.

Although they can be split up into a number of categories, birds have two major feather types: flight feathers and down feathers. Flight feathers are stiff and, because birds can control their Canada Goose Coats On Sale positions, act almost like individual wings. The individual feather “branches” (or, more correctly, barbs) have their own barbules with thousands of little hooks. These hooks hold the barbs together, much like Velcro, to form an air resistant surface that catches air and allows birds to fly. They Canada Goose online also provide a waterproof surface especially important cheap canada goose uk for Canada Goose Parka aquatic birds. The waterproofing is maintained by birds, such as ducks, when they preen. They have an oil gland on their back, the uropygial gland, where their body meets the tail. When canada goose coats on sale they preen they get oil from canada goose clearance sale the gland and spread it on their outer feathers.

A snow goose taking off from a pond, with water on its oiled and canadian goose jacket waterproof feathers.

Downy feathers make up https://www.canadagooseonlineshop.co.uk the majority of feathers on a bird and provide excellent insulation because they trap air between the bird’s body and the air around it. Downy feathers have barbs and barbules just like flight feathers, but a down feather’s structure is different. These barbules don’t Canada Goose Jackets form hooks, but instead branch to create Canada Goose sale more air space, and thus more insulating ability. In especially cold weather, birds can fluff their feathers to provide an even thicker layer uk canada goose of air.

Consider the pink fiberglass insulation common in houses made up of millions of uk canada goose outlet individual fibers with air in between. The thicker the insulation, the higher the R value. When birds fluff their feathers they are increasing their R value. None of Canada Goose Online the synthetic fibers made to imitate down in coats comes close to the insulating properties of bird down, but then nature has been working on cheap Canada Goose feather design 150 million years longer than we have been making synthetic down coats.

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