How does a glass barometer work? — Pat, Kell, Ill.
Marshall Brain Answered:
There are many different ways to create a barometer, but they all break down into two different styles as described here:
What a barometer is measuring is the pressure in the atmosphere. A meteorologist is looking for an exact measurement. But generally speaking (there are a dozen exceptions…), there is a big picture view of pressure as well: when the air pressure is high the weather tends to be fair. When it is low, it is likely to be cloudy and rainy. An old-style glass barometer was a very simple way to see whether the pressure was high or low.
This video shows you one style of glass baraometer – it looks like a little tea pot:
This video shows you the other style – it hangs on the wall:
A glass barometer was also referred to as a weather glass.