Galileo Thermometer is a marriage of science and art. Amazing! 400+ years ago, Galileo discovered that as a liquid"s temperature changes, so will an object"s flotation in it... the relative density. That"s the science behind this cool Thermometer! Five hand-blown glass spheres (8 in 17" unit), each fitted with a metal medallion, float in a craftsman-blown cylinder. They rise and fall. You read the lowest sphere near the top, determining the room temperature to about 1 degree accuracy. Fascinating laws of physics! State Size. 11"h: 2 1/4" diam. base, 13 ozs. 13"h.: 2 7/8" diam. base, 1 lb., 7 ozs. 17"h.: 3" diam. base, 1 lb., 14 ozs. Order Today! Galileo Thermometer