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Phantastic Physics: Airplane Wings

An airplane wing builds upon Bernoulli's principle to create a force of lift on on an airplane wing. Remember that Bernoulli's principle states that faster moving fluids exert less pressure on surfaces they are flowing across than slower moving fluids.   The basic idea behind an airplane wing is to create a shape where the air flows faster over the top surface than on the bottom.  In the animation below you will notice that air is flowing across three separate shapes.

air on wings animation The distance the air particle travels on top of the shape is the same as the distance traveled by the particle on the bottom side. Equal distances in equal times means that the air particle on the top is traveling the same speed as the one on the bottom..  The force of the air on the surfaces then are equal so they add up to no net force ...no lift!
Notice that because the curved is a longer distance than the flat surface from the first shape, the air is traveling faster over the curve.   However, this shape also has equal distances being traveled in equal times so the result is no net force...no lift. 
Since the air particle on the top side is traveling the length of the curve it is traveling faster than the one following the straight line.   The faster moving air exerts less force than the slower air on the bottom, so when these two forces are combined they do not cancel each other out.  There is some net force up...there is lift! 

The faster the airfoil moves through the air the greater this difference between the down force and the up force...so in other words, the faster the wing goes, the more lift it produces. 

The thinner the airfoil is in height, the less lift it will create but it will also create less air friction (known as drag).
The thicker the airfoil the more lift, but eventually you create a wing that has so much drag you can't move it fast enough to create lift.  The secret is to find the "happy medium" which is somewhere in-between too thick and too thin.  Slower moving airplanes require a thicker wing because they don't move fast enough to create lift with thinner wings.  High speed airplane wings (like fighter jets) are nearly flat on both sides because they don't need much of a curved top to create lift at high speeds. At slow speeds (like when trying to land) these high speed airplanes require a way to actually make the wings more curved to create more lift.