The Outdoor Galileo Thermometer, like the traditional indoor version, was invented by Italian scientist Galileo Galilei. He discovered that there was an effect of temperature on the specific gravity of liquids and designed and built a thermometer around this. The Galileo thermometer is a blown glass cylinder filled with liquid and also 11 blown glass balls filled with colorful liquids. Each of these spheres represents a different temperature or range and as the temperature changes, these spheres actually rise and fall. The temperature can then be determined by reading the metal tag on the lowest floating ball. This is the first outdoor version I've seen and measures temperature rrom 50-100° F. Very stylish.