The Galileo Thermometer is an elegant temperature reading device that every science geek needs. It is a sealed glass cylinder that contains clear liquid and glass bulbs that are all different density. As the temperature changes, the balls rise and fall, giving you a temperature reading.\nThe temperature is read from the engraved metal discs that hang off each bulb if a bulb is floating in the middle, that is the current temperature, or if some are at the top and some at the bottom the temperature will between the bulbs on either side of the gap.\nThis Galileo Thermometer is 28cm tall with 6 glass balls (temperature range 18C to 28C).