At the touch of a button, your phone gives you the temperature, 5-day forecast, and more. Your smart thermostat tells you the temperature inside and outside, and lets you adjust accordingly. But it wasn't always this way. Centuries ago, people told the temperature using Galileo thermometers. And recently, they've made a comeback.
History of Galileo Thermometers
The Galileo thermometer was actually not designed by Galileo, but rather by a student of his, with a group of engineers. They first described the device in an academic paper in 1666. Called the Fifth Thermometer, or slow thermometer, the principle was that a liquid's density would change as the temperature grew colder or warmer, which could be used to determine exact temperature.As other, more efficient thermometers were developed, over time the slow thermometer fell by the wayside. Until the 1990s, when London's Natural History Museum started selling them in the gift shop. They've been increasing in popularity ever since.
How They Work
A cylindrical tube is filled with clear liquid, such as water or alcohol. In it is placed a series of glass balls of different weights, also filled with liquid, dyed different colors. Each colored ball represents a different temperature and has a tag attached to indicate it. The heavier the ball, the lower the temperature.Say the temperature is 80 degrees. All the balls tagged higher than 80 degrees are less dense than the surrounding liquid at this temperature, and will float to the top of the tube, with the 80 degree ball floating just beneath them. All others are at the bottom.Then the temperature drops to 75 degrees. The liquid being denser now, the 80 degree ball can float all the way to the top, and the heavier 75 degree ball takes its place, floating just below the others.It's not quite as precise as your thermostat's readings, but it's still perfectly accurate, and a colorful, and useful knickknack to have around the house.
To learn more about Galileo thermometers and other HVAC issues, contact us at Air Assurance. We proudly serve Broken Arrow's heating and cooling needs.