Thermal instruments are devices used to measure temperature or heat. Common examples include thermometers, which can be digital or analog, and thermocouples, which measure temperature differences. These instruments are essential in various fields, including meteorology, cooking, and industrial processes. These instruments operate based on different principles, such as the expansion of liquids in liquid-in-glass thermometers or the electrical resistance changes in thermistors. Accurate temperature measurement is crucial for scientific research, safety, and quality control in manufacturing, ensuring that processes remain within desired temperature ranges.