鲍鱼tv

The flight of birds seems effortless. Waved albatross seem to defy the laws of nature as they are big heavy birds. So how do they stay aloft? The secret is a wing with a thick rounded front edge that curves gently down to the back edge which is very thin. As the bird glides forward the air flowing under the wing is impeded by the wing's downward curve so it becomes slightly compressed. That pushes the wing upwards. At the same time, the air flowing over the wing is deflected upwards by the wings front edge, so reducing its pressure. If the bird is flying fast enough, then the slight suction from above and the push from beneath will be enough the lift the bird into the air and keep it aloft. The trick is to make sure the air flows over the wing quickly enough for this push and pull to keep the bird in the air. Albatrosses also use upward air currents from cliffs and waves and can soar on these updrafts for hours with scarcely a movement of their wings.