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A temperature is an objective comparative measure of hot or cold. It is measured by a thermometer, which may work through the bulk behavior of a thermometric material, detection of thermal radiation, or particle kinetic energy. Several scales and units exist for measuring temperature, the most common being Celsius (denoted °C; formerly called ''centigrade''), Fahrenheit (denoted °F), and, especially in science, Kelvin (denoted K). The coldest theoretical temperature is absolute zero, at which the thermal motion in matter would be zero. However, an actual physical system or object can never attain a temperature of absolute zero. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, and −459.67 °F on the Fahrenheit scale. The kinetic theory offers a valuable but limited account of the behavior of the materials of macroscopic systems, especially of fluids. It indicates the absolute temperature as proportional to the average kinetic energy of the random microscopic motions of their constituent microscopic particles such as electrons, atoms, and molecules. Temperature is important in all fields of natural science, including physics, geology, chemistry, atmospheric sciences, medicine, and biology—as well as most aspects of daily life. ==Effects of temperature== Many physical processes are affected by temperature, such as * physical properties of materials including the phase (solid, liquid, gaseous or plasma), density, solubility, vapor pressure, electrical conductivity * rate and extent to which chemical reactions occur * the amount and properties of thermal radiation emitted from the surface of an object * speed of sound is a function of the square root of the absolute temperature 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Temperature」の詳細全文を読む スポンサード リンク
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