Temperatures

Temperature is a measure of the degree of hotness or coldness of an object or environment. In physics, it reflects the average kinetic energy of the particles in a system and is a scalar quantity that determines the direction of heat transfer, with heat flowing from higher to lower temperatures.

Common temperature scales are Celsius, Fahrenheit, and Kelvin. In the Celsius scale, water freezes at 0 and boils at 100 at one atmosphere of pressure. In Fahrenheit, the corresponding points are 32 and 212. Kelvin uses 273.15 and 373.15, with zero kelvin representing absolute zero, the lowest possible temperature where molecular motion is minimal. Conversions between scales are given by C = (F − 32) × 5/9, F = (9/5) × C + 32, and K = C + 273.15.

Measurement of temperature uses various instruments that detect changes in a physical property. Common devices include liquid-in-glass thermometers, thermocouples, resistance temperature detectors (RTDs), and infrared thermometers. Calibration against standard references ensures accuracy across different environments and ranges.

Applications and concepts associated with temperature are widespread. It is central to weather forecasting, climate science, medicine, and industrial processes. Temperature influences phase changes, chemical reaction rates, and material properties. Understanding temperature involves its relation to heat, energy transfer mechanisms (conduction, convection, radiation), and the behavior of matter under different pressures and conditions.