Galileo Thermometers are magnificent creations that make Galileo's 400 year old principle of relative density a functional reality. This thermometer uses a singul floating red ball to indicate changes in temperature. The Galileo Thermometer is the point at which art meets science. Galileo Thermometers are precisely manufactured. Precise measurements of the liquid filled ball ensure a stately and orderly procession of ups and downs as the temperature changes. How do I read the temperature? Simply read the temperature indicated by the pointers on each side of the floating ball. As the temperature increases or decreases the red floating ball inside of the liquid filled thermometer rises and falls. How accurate is this Galileo thermometer? It measures temperature from 50° F to 104° F (10°C to 40°C) and is accurate to within 5°