Temperature
Definition of Temperature
Temperature signifies a quantification of the mean kinetic energy of particles within a substance or system. This essential attribute of matter serves to discern the hotness or coldness of a given object or environment. Various temperature scales allow for the measurement of temperature, namely Celsius (°C) , Fahrenheit (°F) , and Kelvin (K) .Measuring Temperature
Numerous instruments facilitate temperature measurement, including the following:Thermocouples: These apparatuses comprise two distinct metals conjoined at one terminus. They produce a minor voltage proportional to the temperature differential between the two extremities.
Resistance temperature detectors (RTDs) : These sensors exploit the alteration in electrical resistance of a substance (frequently a metal) with temperature to ascertain the substance's temperature.
Thermistors: Operating similarly to RTDs, thermistors are temperature-responsive resistors. They generally comprise ceramic materials and exhibit a substantial resistance change with temperature.
Liquid-in-glass thermometers: These conventional instruments incorporate a liquid (mercury or alcohol commonly) , and this liquid expands or contracts corresponding to temperature variations, traversing up or down a graduated scale inside a glass tube.
Temperature Scales
Three principal temperature scales find widespread use:Celsius (°C) : This scale, formulated by Anders Celsius in 1742, situates the freezing point of water at 0°C and the boiling point at 100°C under standard atmospheric pressure.
Fahrenheit (°F) : Daniel Fahrenheit introduced this scale in 1724, positioning the freezing point of water at 32°F and the boiling point at 212°F under standard atmospheric pressure.
Kelvin (K) : William Thomson, Lord Kelvin, proposed this scale in 1848. The Kelvin scale, an absolute temperature scale, establishes its zero point at absolute zero (-273.15°C or -459.67°F) , the minimum conceivable temperature where all molecular motion halts.
