Galileo Thermometers are magnificent creations that make Galileo s 400 year old principle of relative density a functional reality. Each Thermometer is encased in brilliant glass with many multi-color floating balls. A gold tag that displays a temperature in Fahrenheit hangs beneath each ball. The Galileo Thermometer is the point at which art meets science. Galileo Thermometers are precisely manufactured. Each of the liquid-filled floats weighs exactly .006 grams more than the one above it. Precise measurements of the liquid filled balls ensure a stately and orderly procession of ups and downs as the temperature changes. How do I read the temperature?. To tell the temperature you read the tag on the lowest of the floating balls. This is Galileo's 400 year old principle of fluid density at work. As the temperature of the fluid in the cylinder increases the pressure drops and the liquid becomes less dense. When the precisely measured floats reach their specific calibrated temperature they drop. As the temperature of the liquid cools the process is reversed and the floats rise from the bottom of the cylinder. Functional and decorative. It has temperature gradients of 4 degrees F from 64 degrees F to 80 degrees F and is accurate to within 4 degrees. Uses science principles developed by the famous Italian physicist Galileo Galilei. Tags beneath each ball indicate the temperature.