Ambient Weather BA30806 Frost Globe Map Storm Hand Blown Glass Barometer

The concept that 'decreasing atmospheric pressure predicts stormy weather' was postulated by Lucien Vidie -- and it's the basis for a weather prediction device called a storm glass or liquid barometer. It consists of a glass container with a sealed body, half filled with water.

A narrow spout connects to the body below the water level and rises above the water level, where it is open to the atmosphere. When the air pressure is lower than it was at the time the body was sealed, the water level in the spout will rise above the water level in the body and when the air pressure is higher, the water level in the spout will drop below the water level in the body.

Note: You can vary the water color by adding the food coloring of your choice. The image above is shown with blue fluid.