Alcohol thermometer Duke of Tuscany, who in 1654 made sealed tubes partly filled with alcohol or urine, with a bulb and stem, depending on the expansion of a liquid, and independent of air pressure. Other sources, including the Encyclopædia Britannica, credit German scientist Daniel Gabriel Fahrenheit with inventing the alcohol thermometer in 1709. Fahrenheit was a skilled glassblower and his alcohol thermometer was the world's first reliable thermometer. Alcohol thermometer The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will
Mercury-in-glass thermometer Nowadays, the triple point of water is used instead of the freezing point (the triple point occurs at 273.16 kelvins (K), 0.01 °C). Before the discovery of the true thermodynamic temperature, the thermometer "defined" the temperature; thermometers made with different materials would define different temperature scales (a coloured alcohol thermometer would give a slightly different reading than a mercury thermometer at, say half-scale). In practice, several materials gave very similar temperatures to each other and, when discovered, to the thermodynamic temperature. One special kind of mercury-in-glass thermometer, called a maximum thermometer, works by having a constriction in the neck close