GALILEO THERMOMETERS

These thermometers are based on a principle discovered by Galileo, according to which the density of a liquid changes with temperature. These thermometers consist of small balls of different specific gravity and temperature readings, which are placed inside a cylinder with liquid. As the temperature rises, the density of the liquid decreases causing the balls with the highest specific gravity to sink slowly to the bottom. The ball with the smallest temperature indicator at the top of the liquid cylinder indicates the temperature.