The Galileo Thermometer is an elegant temperature-reading device that every science geek needs.

The thermometer is in a sealed glass cylinder that contains clear liquid and glass bulbs of different densities. As the temperature changes, the balls rise and fall, giving you a temperature reading.

The temperature is read from the engraved metal discs that hang off each bulbif 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 be between the bulbs on either side of the gap.