Galileo Storm Glass Weather Station - Science Behind Beauty

Posted by John Lopez on January 24th, 2020

Galileo Storm Glass Weather Station - Science Behind Beauty

The Italian scientist, Galileo Galilei, created one of the first thermometers in the late 1500s. This is the most unique storm glass weather station of all time. Have you ever seen Galileo Thermometer? It looks the pretty cool way of showing what the temperature is and it also raises the standard of decoration in your home with its cool features. The storm glass has little bubbles with different color liquid inside of them. Each little bubble has a tag on them with a different reading of the temperature. You read a Galileo thermometer by reading the tag on the lowest bubble that is still floating. The way the thermometer works to change to different temperatures involves a bit of physics.

The most beautiful way to measure the temperature than using Galileo Storm Glass Weather Station. This fairly accurate instrument is based on the thermoscope invented by Galileo Galilei in the early 17th century. Unlike your typical mercury-in-glass thermometer that’s basically a narrow bulb made with mercury that expands and contracts, the Galileo thermometer is far more complex. It’s comprised of multiple glass spheres each filled with a colored liquid mixture that often contains alcohol but can even be simply water with food coloring added. These floating balls sink or float inside the surrounding water over time and temperature ever so slowly and gracefully.

Science Behind Storm Glass Weather Station and Galileo Thermometer

An object immersed in fluid experiences two forces, the downward force of gravity and the upward force of buoyancy. In the Galileo thermometer, its the downward force of gravity that makes it work. Each of the tags on the different bubbles as a different calibrated weight, making each one a slightly different weight from the others. The liquid inside each of the bubbles has the same density so that when the weighted tags are added, each bubble has a slightly different density than the others due to the ratio of mass to volume. The density of all of the bubbles is very close to the density of the surrounding water. Therefore, as the temperature outside the thermometer changes, the temperature of the water the bubbles are immersed in also changes. When the temperature of the water changes, it either expands or contracts which changes its density. So at any given density, some of the bubbles will float and others will sink. So for example, if the temperature is increasing, the density of the water decreases. So the bubble with a tag that says 72 degrees, for example, will have now have a weight per unit volume that is greater than that of the surrounding water rather than lighter, and it will sink to the bottom. Very neat!

The blue bubble (60 degrees) is the heaviest (densest) bubble, and each bubble thereafter is slightly lighter, with the red bubble being the lightest. Now, let's say the temperature in the room is 70 degrees. Since the surrounding air is 70 degrees, we know the water inside the thermometer is also about 70 degrees. The blue and yellow bubbles (60 and 65 degrees, respectively) are calibrated so that they have higher densities than the water at this temperature, so they sink. The purple and red bubbles each have a density that is lower than the surrounding water, so they float at the very top of the thermometer. Since the green bubble is calibrated to represent 70 degrees, the same temperature as the water, it sinks slightly so that it is floating just below the purple and red bubbles -- thereby indicating the room's temperature!