13 inch Galileo Thermometer

I've seen these sporadically through my life and was very confused on what they were? Entrapped funky fishing bobbers? Actually no. Just recently I found out their Thermometers and once you know how they work it really is a way cool bubble gum for the eyeball gizmo!! Crafted in Germany, this 13" tall functional and attractive desk accessory is a thermometer based on the physicist Galileo Galilei?s (1564-1642) discovery that the density of fluid expands and contracts depending on temperature. Hand-blown glass spheres feature medallions imprinted with temperatures ranging from 64'F to 88 'F. The lowest floating sphere in the upper group indicates the current temperature. As the temperature decreases, spheres will rise and as the temperature increases, spheres will fall. From WonderfullyWacky.com...