The main purpose of a thermometer is to measure temperature. Thermometers come in various types, including mercury, digital, and infrared, and are used in many fields, such as meteorology, medicine, and cooking. In a medical context, thermometers measure body temperature, helping to determine if a person has a fever or other health issue. In scientific applications, they can monitor environmental temperatures or assist in chemical reactions where heat control is essential. The accuracy of temperature measurement is critical in all these settings, making thermometers essential tools for understanding thermal conditions and ensuring proper functioning in various processes.