The G.W. Schleidt Galileo Thermometer was originally invented 400 years ago by Galileo Galilei, a pioneer of modern physics and astronomy. The clear glass cylinder contains multi-colored spheres with numerical tags suspended in a special, clear liquid. Galileo discovered that spheres of different weights rise or fall according to the temperature as the liquid in the cylinder contracts (cools) and expands (warms). The lowest floating sphere in the upper part of the cylinder tells the current temperature. This 12-inch version comes in a geometric square stand and registers temperatures from 60 to 84 degrees Fahrenheit.