The Goethe Weather Ball Barometer is a specially designed glass filled partially with liquid. Once filled with liquid, a pocket of sealed air with a constant pressure is created inside the device. As the atmospheric pressure changes outside of the glass, it will affect the this sealed air. A high atmospheric pressure system will push the liquid down the spout, as the outside air is heavier than the trapped air inside. Low pressure will cause the trapped air to be heavier than the outside air and will push the water up the spout. High atmospheric pressure or a “low reading” in the spout usually indicates fair weather, while a “high reading” in the spout usually forecasts poor weather or a low pressure system. Although the storm glass will not indicate exact barometric pressure in numerical values, it is still regarded as an accurate monitor of air pressure changes.
When you receive your Goethe Weather Ball Barometer it will not be filled with liquid. Follow the enclosed directions and use the supplied syringe to fill the Barometer with any color water desired. Be sure to use standard food coloring to avoid staining the glass. It is recommended to mix the color in a separate container prior to injecting it into the glass.