So you want to know the history behind the storm glass barometer. How does it work? Read on to learn more!
A storm glass barometer is a device used to measure atmospheric pressure. Johann Wolfgang Von Goethe popularized the storm glass barometer using principles established by Evangelista Torricelli. Torricelli is credited as the actual inventor of the barometer, but it should be noted that he invented the mercury barometer. Goethe, who might have understood the dangers associated with handling and working with mercury, decided water was a safer alternative that worked just as well.
How does the storm glass barometer work?
The storm glass has a sealed body and a long spout. The long, narrow spout is connected to the sealed body below the intended water level, and extends to rise above the intended water level at the top. When the sealed body is filled halfway with water, air pressure is trapped within the body and is held constant.
The spout, however, is open to the outside air pressure, which is always changing. When the air pressure is low, the air inside the sealed body is heavier and pushes water up the spout – as a result, the water level in the spout rises above the water level in the sealed body. On the other hand, when the air pressure is high, the outside air is heavier and the water level in the spout will be pushed down – as a result, the water level in the spout drops below the water level in the sealed body.
So what does this mean? Well, low air pressure is less stable and often leads atmospheric instability causing “stormy” or rainy weather. High pressure creates a “dome” of stable air and can be associated with clear, calm weather. When water moves up the spout, this signals the onset of rainy or stormy weather with the coming of less stable air. Barometers even have the ability to indicate the onset of potentially severe weather – watch for a rapidly rising water level.
How accurate are storm glass barometers?
Storm glass barometers are very sensitive and will indicate changes in atmospheric pressure almost immediately. In fact, storm glass barometers are sensitive enough to register the slight air pressure difference between the attic and basement of a three-story house. Developed in the mid 1600’s, it is quite amazing that barometers are still widely used as means of reliable weather forecasting today. In fact, a barometer can even be as accurate, if not more so, than your local news station weatherman or certified meteorologist.
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