One of the most fascinating inventions to watch in action is the Galileo thermometer.

This glass tube, filled with clear liquid and floating glass balls that contain different colour solutions, is designed to offer a reading of temperature. As temperature changes, the density of the liquid in the tube alters. This causes the glass balls to move either up, as the temperature drops, or down, as temperatures rise.

Galileo Galilei didn’t invent this specific thermometer, but it uses the basic principles he established regarding the relationship between liquid density and temperature. This is where this captivating modern interpretation of his work gets its name from.