The Thermoscope/Thermometer
During the 17th century there was no clear way to examine heat correctly.
In Venice, where Galileo worked and studied there was a concern about how to measure heat. The first solution that was thought up would be the Thermoscope.
The first versions were thought of as toys; the idea of the expansion of air as its heat increased was played with by many scientists of the time.
"He took a small glass flask, about as large as a small hen's egg, with a neck
about two spans long [perhaps 16 inches] and as fine as a wheat straw, and
warmed the flask well in his hands, then turned its mouth upside down into the
a vessel placed underneath, in which there was a little water. When he took
away the heat of his hands from the flask, the water at once began to rise in
the neck, and mounted to more than a span above the level of the water in the
vessel. The same Sig. Galileo had then made use of this effect in order to
construct an instrument for examining the degrees of heat and cold."
Benedetto Castelli wrote in 1638 about a device he had seen in Galileo's hands around 1603
Over the next several years this thermoscope was developed by Santorio Santorio and Galileo's friend Gianfrancesco Sagredo (both who worked and studied in Venice), Galileo, and others to include a numerical scale. It had then become a full-fledged air thermometer.
In Venice, where Galileo worked and studied there was a concern about how to measure heat. The first solution that was thought up would be the Thermoscope.
The first versions were thought of as toys; the idea of the expansion of air as its heat increased was played with by many scientists of the time.
"He took a small glass flask, about as large as a small hen's egg, with a neck
about two spans long [perhaps 16 inches] and as fine as a wheat straw, and
warmed the flask well in his hands, then turned its mouth upside down into the
a vessel placed underneath, in which there was a little water. When he took
away the heat of his hands from the flask, the water at once began to rise in
the neck, and mounted to more than a span above the level of the water in the
vessel. The same Sig. Galileo had then made use of this effect in order to
construct an instrument for examining the degrees of heat and cold."
Benedetto Castelli wrote in 1638 about a device he had seen in Galileo's hands around 1603
Over the next several years this thermoscope was developed by Santorio Santorio and Galileo's friend Gianfrancesco Sagredo (both who worked and studied in Venice), Galileo, and others to include a numerical scale. It had then become a full-fledged air thermometer.