Galileo Thermometer - Fahrenheit. The Galileo thermometer consists of a sealed glass tube that is filled with water and several gloating bubbles. The bubbles are glass spheres filled with a colored liquid mixture. Attached to each bubble is a little metal tag that indicates a temperature. A number and degree symbol are engraved on these calibrated counterweights. The bulb that sinks the most indicates the approximate current temperature. Range is 64 to 80 Farenheit. 13 inches in length.