Allen Brelsford, age 7, of Ohio, for his question:
How does the weatherman measure the speed of the wind?
The men of olden sailing ships listed twelve different kinds oP wind from calm to howling hurricane. Our weatherman still uses this listing called the Beaufort scale when he reports the wind as a moderate breezes a moderate gale or a hurricane. But, unlike the old time sailors he has instruments which tell him exactly how hard the wind is blowing how fast it is traveling.
The wind is named after the direction from which it comes; You can remember this because the North Wind is often cold, since it may have blown from north polar regions. Any gadget for measuring the speed of the wind must also be able to swing around and face the direction froth which it comes. All these gadgets make a node of wind direction.
The wind is really air on the move, moving air pushes against anything in its path. The faster it moves the harder it pushes and the greater its pressure. The machines for measuring the exact speed of the wind are called anemometers. All of them are hoisted where they can catch a true picture of the breezes. They can be fixed with dials to show how things are blowing and they can be attached to electrical equipment for making permanent records on graphs. They can also be coaxed to relay their information to the weather men who prefer to do their observing indoors.
The deflection anemometer is a hinged board hoisted into the pushing wind, The stronger the windy the further the board is bent over towards the horizontal. Sections marked on an arc show how many miles per hour the wind must be blowing to make it bend thus far,
The Robinson cup anemometer uses three or four metal cups, fixed on a swivels each facing the back of the one in front: The harder the wind blows the faster they spin around. The up to date Bendix Friez aerovane looks the most at home in our jet Age: The vane part which guides it into the wind, is like the tail end of a super plane. The fronts which checks wind speed, is a three bladed propeller. The best recording of gusty winds is done by the Gurley electronic anemometer. This is a three cupped affair which records its findings by a high frequency oscillator.
These are some of the gadgets that make accurate, miles per hour records for the sailors old classifications. When the weatherman says moderate breezes he knows the wind is blowing from 13 to 18 miles per hour. A moderate gale is 32 to 38 miles per :hour; All traffic speeds are scrapped when the wind reaches 75 miles per hour That is the sailor’s old classification for hurricane and up go the two red danger signals.