The Galileo thermometer, used to measure temperature, is mainly used for home décor nowadays. The stylish thermometer used in people’s homes today is based off of a thermo scope Galileo invented in the early 1600’s. Although not exact, the Galileo thermometer is moderately accurate. The thermometer has several glass blown bubbles, with a colored liquid inside which is just for decoration. The bubbles have metal tags attached to the bottom of them with an engraved number on it, for example seventy, for seventy degrees Fahrenheit. The glass bubbles float in a water filled glass tube, which may vary in size. The glass bubble floating, usually on its own in the middle of the tube, is what the temperature is approximately, but how exactly does floating glass measure temperature?
The glass bubbles in the Galileo thermometer are adjusted to specific densities by the differing amounts of liquid and even the type of liquid within the glass. The different densities will be affected by the waters density, which changes as it expands or contracts with temperature difference. As the temperature within the room heats up, so does the temperature of the water within the vertical glass tube. Once the water within the thermometer is room temperature, the glass bubbles densities will either be more or less dense than the water. Depending on the temperature, the glass bubbles will either sink or float. The one glass bubble that is either in the middle of the tube, floating near the top but sinking slightly, or sinking near the bottom but floating slightly, is the temperature of the room.
For example, if it is seventy degrees Fahrenheit in the room, the glass bubbles labeled sixty and sixty-five, having the highest densities, will sink, while the glass bubbles labeled seventy-five and eighty, having the lowest densities, will float, seventy will be somewhere in between. Obviously there are temperatures other than those five, which is why the Galileo thermometer is not the most accurate reading of temperature. The Galileo thermometer is used for decoration because if someone wanted a real reading of temperature, they would most likely not go to a thermometer where the reading would be seventy-ish degrees Fahrenheit.
Although the Galileo thermometer is named after Galileo, the thermometer he invented, properly called a thermo scope, did not have the same properties as the actual Galileo thermometer. I believe the reason it is named after Galileo is because he did, with his invention of the thermo scope, figure out that with a temperature change the water’s density will change too. This is the reason behind why today’s Galileo thermometer works the way it does.
In conclusion, the Galileo thermometer, named after Galileo’s discovery of water’s density changing with temperature, measures temperature with glass bubbles varied in densities. Although functional, the Galileo thermometer is not the most accurate reading of temperature today due to the lack of specific temperature increments. With its sleek design, it is pleasing to the eye, which is why in most cases people today have these in their homes or offices.
Heckert, Paul A. “Galileo’s Thermometer” Suite 101. 7 Mar. 2007. 5 Mar. 2009 .
“How Does a Galileo Thermometer Work” How Stuff Works. HowStuffWorks inc. 5 Mar. 2009 .
Przewoznik, James. “Galileo Thermometer Operation” Ask A Scientist. 7 Feb. 2005. 5 Mar. 2009 .