Temperature (Energy)

Temperature is a fundamental physical property that quantifies the average kinetic energy of the microscopic particles within a substance, determining the direction of thermal energy flow between objects in contact. Measured with devices such as liquid-in-glass thermometers, thermocouples, and optical pyrometers, it relies on temperature-dependent phenomena like thermal expansion or electrical resistance. The SI base unit for thermodynamic temperature is the kelvin, while the Celsius and Fahrenheit scales remain widely employed across science, industry, meteorology, and daily life.