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We have three models in digital thermohygrometers available.
A Galileo thermometer (or Galilean thermometer) is a thermometer made of a sealed glass cylinder containing a clear liquid and several glass vessels of varying densities. As temperature changes, the individual floats rise or fall proportion to their respective density. In the Galileo thermometer, the small glass bulbs are partly filled with different-coloured liquids. The composition of these liquids is not important for the functioning of the thermometer; they merely function as fixed weights and their colours are only for decoration. Once the handblown bulbs have been sealed, their effective densities are adjusted by means of the metal tags hanging from beneath them. Any expansion due to the temperature change of the coloured liquid and air gap inside the bulbs does not affect the operation of the thermometer, as these materials are sealed inside a glass bulb of fixed size. The clear liquid in which the bulbs are submerged is not water, but some organic compound (such as ethanol) whose density varies with temperature more than water's density does. This change of density of the clear liquid, with temperature change, causes the bulbs to rise or sink.