The story behind

The world's first thermometer

A Gaileo Galilei glass is a thermometer and measures the temperature.

In 1593, astronomer, physicist, engineer and “father of advanced science” Galileo Galiei discovered that the volume of a liquid changes when the temperature changes. Galileo, with the newly discovered fascinating knowledge of Galileo Galilei, created the glass and was the first to invent a tool that could measure temperature variations. In the years that followed, the thermometer was further developed by Galileo, Santorio Santorio and Galileo’s friend Gianfrancesco Sagredo, and Gabriel Fahrenheit and Anders Celcius invented the two temperature scales that today can both be read on the Inca Living Galileo Galilei glass.

Portræt af opfinderen af termometeret Galileo Galilei
Galileo Galilei eksperimenterer med termometeret der senere bliver til Inca Living Galileo Galilei glasset

A first-hand account of discovery

In 1603, the Italian physicist and mathematician Benedetto Castelli described Galileo’s discovery of the thermometer as follows.

“Galileo took a small glass flask, the size of a small hen’s egg, with a neck about two clasps long and as fine as a wheat straw, warmed the flask well in his hands, and then turned its mouth down into a vessel placed underneath, in which was a little water. As he took the heat from his hands off the flask, the water at once began to rise in the neck, and rose to more than a span above the water in the tub. Galileo made use of this effect to construct an instrument for estimating heat and cold.”

The Galileo Galieli glass is an ever-changing thermometer

The appearance of the glass changes with changes in temperature.

The Galileo Galilei glass contains four precisely calibrated glass spheres floating in a liquid. On each glass ball is a small metal sign with a temperature indication. As the temperature in the room rises, the glass spheres fall. When the temperature in the room drops, the glass spheres rise. For example, the 18-degree glass ball will drop when the temperature in the room gets above 19 degrees. Conversely, the 18-degree glass sphere will rise when the temperature in the room drops below 17 degrees.

If a glass ball is floating in the middle of the cylinder, the temperature is between the number on it and the number on the lowest floating glass ball at the top of the cylinder.

If all glass spheres float at the top of the cylinder, the temperature is lower than the number of the lowest floating glass sphere.

If all the glass spheres are floating at the bottom of the cylinder, the temperature is higher than the number of the highest floating glass sphere.

Produktfoto bagfra af Inca Living Galileo Galilei glas i kobber på hvid baggrund