Understanding the origin of uncertainty in thermometer calibration

摘要

Thermometers have widespread application, ranging from their role in measuring temperature in common consumer goods to integration in sophisticated medical and industrial technology or processes. Like any measurement device, they must be calibrated against the International Temperature Scale of 1990(ITS-90). ITS-90 is based on fixed-points at which a pure metal changes its phase by melting or freezing. During the phase change process, heat is either absorbed or released by the metal without changing its temperature. At a fixed point, a thermometer immersed in it observes a temperature plateau that can be used as a practical reference.