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You don't need a weatherman to tell which way the wind blows |
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Written by Administrator
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Friday, 27 February 2009 |
Have you really ever thought about wind?
I mean, really thought about it?
Wind is an amazing phenomenon. Any science geek can tell you the scientific definition of wind is the horizontal movement of air caused by differences in air pressure due to uneven heating of the Earth. But that sounds so un-poetic.
What really is wind?
It is a mysterious force that can level buildings, make an airplane fly or keep a child’s kite in the air.
It is hard to measure since, unless there is some sort of pollution involved, you can’t see it. Weather vanes have been around for centuries and can tell you which way the wind is blowing. And special monitors can measure the strength of the wind, but those measurements are all subjective. They can only tell you how strong the wind is at that certain place.
Where does wind start? For that matter, where does it end? There must be some place that can be classified as the starting point for a wind gust. Does a wind gust just magically appear at point A and then, just as magically vanish at point B. Or does it gradually build up like rush-hour traffic and gently disperse over distance?
How wide is a wind gust? Can I be standing in a field and feel the wind on my face when someone 10 feet away from me not feel a thing? Is it stronger in the middle of the gust, or does it vary throughout?
I figure as wind passes objects, such as trees and buildings, it looses a little bit of its overall power. But taking this thought experiment a little further, it could also speed it up.
Using the Bernoulli Principal, the air moving around an object has to increase speed to catch up to the air not affected by the object. Wind moving through a forest or city will have lots of these fast moving currents. True, the energy will diminish, but the speed will pick up.
Try a little experiment. Grab a cotton ball or tissue and hold it at arms length. Now blow. You can see it flicker and wave as your breath passes by. Now put the object on the other side of the room and try again. Nothing, right?
That shows how much energy is required to make wind.
Even if you had a room full of people trying to blow that tissue around, it would leave most of them breathless before you produced any significant movement.
For hundreds of years mankind has been trying to harness the power of wind. Picture the windmills that dot the countryside in Holland. The islands of Hawaii use wind to collect fresh drinking water from the ocean. And there are scientists striving to use the power of wind as an efficient alternative energy source.
But I prefer to leave that sort of thing to the professionals.
Myself, I prefer to sit in the dandelion patch on a blustery day and watch the seed float in the wind. |
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