Medical thermometer measurable scale on the thermoscope and wrote of it in 1625, though he possibly invented one as early as 1612. His models were bulky, impractical and took a fair amount of time to take an accurate oral reading of the patient's temperature. Two individuals switched from water to alcohol in the thermometer. Fahrenheit also created the temperature scale which is named after him, having recorded the system in 1724. The scale is still only mainly used for everyday applications in the United States, its territories and associated states (all served by the U.S. National Weather Service) as well as the
Medical thermometer is less of a problem with a coloured liquid. In the 1990s it was decided that mercury-based thermometers were too risky to handle; the vigorous swinging needed to "reset" a mercury maximum thermometer makes it easy to accidentally break it and spill the moderately poisonous mercury. Mercury thermometers have largely been replaced by electronic digital thermometers, or, more rarely, thermometers based on liquids other than mercury (such as galinstan, coloured alcohols and heat-sensitive liquid crystals). Phase-change thermometers use samples of inert chemicals which melt at progressively higher temperatures from 35.5 °C to 40.5 °C in steps of 0.1 °C. They