A traditional way to read the temperature.
In 1593, Galileo Galilei discovered that the density of liquids reacts predictably to changes in temperature. Having made this discovery, Galileo invented a device that allowed temperature variations to be measured. This elegant sealed glass sphere contains five floating glass bulbs, and is a modern take on Galileo’s invention.
The floating glass bulbs contain coloured liquid, all with the same density. Each bulb has a calibrated, weighted metal tag. When the temperature drops, the liquid inside the thermometer becomes more dense, which causes the bulbs to float. The temperature is determined by the lowest floating bulb. When there is a bulb in the middle, the temperature should be read as between this degree and the lowest floating bulb.
