Galilei discovered that the volume of a liquid changes with temperature, and the Galilei Glass utilizes this principle. The volume of the liquid increases with the temperature, while the volume of the glass beads remains virtually unchanged. Because it expands, the density of the liquid decreases. The buoyancy of the beads is equal to the mass of the displaced amount of liquid. Therefore, as the temperature rises, the fluid's carrying capacity decreases. This can be exploited by producing the balls with a few milligrams of difference in weight. The heaviest ball drops first, and thus has the lowest temperature indication and so on.
The Galilei glass is equipped with 4 glass balls, 18, 20, 22 and 24ºC. You read the temperature as follows -
18 ° C or less All 4 balls will be at the top
20 ° C 3 balls above, 1 ball below
22 ° C 2 balls above, 2 balls below
24 ° C 1 ball above, 3 balls below
Over 24 ° C All 4 balls collected below
When the temperature rises and a ball begins to sink, one can observe the interesting phenomenon that the ball drops very very slowly; why? When
the liquid is heated in the glass, the hot liquid will look upwards and a layer splitting occurs , so that the liquid at the top of the glass is quite a bit warmer than the liquid at the bottom. When, for example, The 20º ball thus floats in the middle of the glass, assuming that the temperature is 21º.
Finished in brass, the Galilei Glass comes complete with a holder, allowing it to be wall hung. 145mm high