A thermometer measures temperature. This device can gauge the warmth or coolness of an object, substance, or environment. Various types of thermometers exist, including mercury, digital, and infrared models, each suitable for different applications, such as measuring body temperature, outdoor temperatures, or the heat of an environment. Mentally, temperature readings influence many aspects of daily life, from healthcare evaluations to weather forecasts. Understanding how temperature fluctuates can also be crucial in scientific and industrial applications, ensuring safety and efficiency in various processes and environments.