Monday, July 31, 2006

Bernoulli's Principle

At certain moments the order of the universe as we know it astounds me. One of those moments (or, better, a kind of those moments) is flying in an airplane.

Some time ago this guy named Bernoulli (or at least I think that’s what his name was; if I’m wrong, someone will correct me) discovered an important characteristic of air. He discovered that when air is moving over a surface it exerts less pressure upon that surface than when the air is still. Better yet, he found that the higher the speed of the air across the surface, the lower the pressure. This knowledge came to be known as Bernoulli’s (if that was his real name) Principle.

So what? you’re thinking. Big whoop. Maybe you’re remembering that kindergarten exercise of taking a piece of paper and holding one edge up to your bottom lip and blowing, then seeing the paper rise to the occasion. Maybe you were more interested in colouring that piece of paper or tearing it up or perhaps laying it down altogether and eating Crayola (because they do taste better) crayons. And maybe when it came time to actually give the principle an equation (in high school physics) you were more interested in that early-blooming girl across the room than in cracking the spine of your Bartleby, Grumman, and Oppenheimer (4th Edition) textbook.

Alright, so was I.

But now it fascinates me. Why? Because I’m looking out over the wing of a 747 jumbo jet that cruises at twenty-some thousand feet over Lake Michigan. And a “wing” is little more than a three-dimensional application of Bernoulli’s Principle. No, we don’t need to go into the physics involved. But even if you’re a physics professor, how can you not be astounded at the fact that two forty-foot-long metal wings can take these umpteen thousand tons and hundreds of people to twenty-some thousand feet above sea level and across an ocean? All because some little law of the universe involving the velocity of speeding molecules!

Of course, this is just the beginning. Birds have been using the same principle since long before humans dreamt of flying on their own (if we can call it that). Jet engines are involved—another wonder of human achievement. Beneath the historical process from observing birds serving wine at twenty thousand feet is an amazing human ability to observe, induce, deduce, and experiment until dream becomes reality. It’s thrilling, really.

The interwoven threads of universal laws, observation, logic, and will produce a beautiful tapestry, a surpassing gift from our Creator. I dare say that this gift, with all the colourful images woven into it, exceeds in value the gifts of early-blooming women and even Crayola crayons.

~emrys

1 comment:

Stephen said...

If only it were so simple. :)Bernoulli's principle is an incomplete - if not incorrect - reason for why a wing works the way it does. Newton's 3rd law, the Coanda effect, and the angle of attack of the wing all play a role. See http://www.aa.washington.edu/faculty/eberhardt/lift.htm