Skip to content

Understanding How Storm Glasses Use Chemistry to Indicate Weather Shifts

There are many tools used by meteorologists to measure and predict the weather, but the storm glass is one of the most interesting and conversation-starting ones. This unique glass device, which is filled with liquid and is also known as a weather glass or camphor glass, has a long history of being used to predict storms at sea and on land. Even though they aren’t as scientifically sound as current technology, storm glasses are still a common decorative item in many homes, which adds to their allure.

In its most basic form, storm glass is a sealed glass jar that holds a mix of liquid chemicals such as water, camphor, potassium nitrate, ammonium chloride, and ethanol. When the temperature and pressure change, the liquids react and crystallise in interesting ways. Storm glass fans would carefully look at how the crystals, bubbles, precipitates, and solubility in the glass changed to figure out what kinds of weather were coming.

The Starts and History

French astrologer Goadoud made the first “weather dial” in the 1600s, which is where the storm glass got its start. His crude device used glass vials filled with distilled water, which expands and shrinks very slightly as the weather changes. During the height of naval exploration in Western Europe, making accurate weather forecasting tools for ships going through rough oceans was a top concern.

Admiral Robert FitzRoy of the British Royal Navy added camphor, salt compounds, and alcohol to storm glass in the middle of the 1800s to make it what it is today. FitzRoy’s model made it more interesting to look at how crystallisation and solubility changed in response to changes in temperature and pressure. FitzRoy storm glasses were a prized ship’s tool and a fun thing to have in the drawing room during the Victorian era.

How does it do its job?

The exact scientific forces at work inside a storm window are still not fully known, but the main way it works depends on how solubility, temperature, and air pressure are all connected. When the atmospheric barometric pressure goes up or down, it has a direct effect on how the chemicals in a miscible solution dissolve or crystallise out of the solvent. At the same time, changes in temperature cause the liquid parts to slightly expand or shrink in volume.

The camphor crystals floating in the room create the amazing sight that still amazes people who own storm windows today. Because it is less soluble when the glass body warms up during high pressure systems, more camphor crystallises out in beautiful branching patterns. Then, when low pressure comes back, the camphor quickly dissolves back into solution. These special qualities make it possible to do simple things like measure and predict the weather that interested early explorers.

What It Means Today

Of course, modern meteorology doesn’t use cutely simple storm glasses. Instead, it uses high-tech tools like Doppler radar, atmospheric data buoys, and complicated computer modelling. Changes in air pressure, which are at the heart of how a storm window works, do, however, show real signs of short-term weather changes. Even though storm glasses are more of a conversation piece than a revolutionary way to tell the weather, their crystalline dance and marine history show how inventive people were in the 19th century.

Featured News