A Galileo thermometer is a temperature measuring gadget invented by Galileo Galilei within the sixteenth century. It consists of a sealed glass cylinder stuffed with a liquid, similar to water or alcohol, and a number of other glass bulbs of various densities suspended contained in the liquid. Every bulb accommodates a steel tag indicating the temperature at which it is going to sink to the underside of the cylinder.
To learn a Galileo thermometer, merely observe which bulb is floating on the backside of the cylinder. The temperature indicated on the tag of that bulb is the present temperature. Galileo thermometers are comparatively correct and may measure temperatures starting from about -10 to +50 levels Celsius.