Room temperature

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Room temperature, in scientific usage, is taken to be roughly 20 to 25 degrees Celsius (°C) (68 to 77 degrees Fahrenheit (°F), 528 to 537 degrees Rankine (°R), or 293 to 298 kelvins (K))<ref>The American Heritage® Dictionary of the English Language, Fourth Edition.</ref>, although it is not a precisely defined term. For numerical convenience, either 20 °C or 300 K is often used. For human thermal comfort, a range of temperatures and relative humidities are acceptable.

The term 'room temperature' is also used in circumstances not directly related to scientific experimentation. For example, it is sometimes said that red wine should be consumed at room temperature.


[edit] As a condition for performing physical experiments

The progress and results of many scientific and industrial processes depends little or not at all on the temperature of the surroundings of the equipment. For example, a measurement of the charge of the electron does not depend upon the temperature of the test equipment. In such cases if any mention of temperature is made, it is customary and sufficient to speak simply of "room temperature", which essentially implies simply that what is being spoken of has not been specifically heated or cooled. Usually this means a temperature at which many people are comfortable, around 20 °C. In most cases considerable temperature variations are irrelevant; work may be carried out in winter or summer without heating or air-conditioning, without mention of the temperature. However, productivity is dependent on thermal comfort.

The phenomena that researchers may choose to study at room temperature can naturally occur in the range of 20 to 25 °C, or they may not. Researchers will choose to study a process outside its natural temperature range when they expect the conclusions to a specific question to be the same at room temperature as at a more natural temperature.

Experimentalists have an advantage in anticipating aspects of a room-temperature experiment, because the temperature is close to 25 °C (77 °F, 537 °R, 298 K), at which many of the material properties and physical constants in standards tables have been measured (more at standard state). By consulting such tables a researcher may estimate, for example, how fast a chemical reaction is likely to proceed at room temperature.

Unless there is a reason to work at a specific temperature, it is clearly more convenient not to control the temperature. Even in cases where a known, controlled, temperature is advantageous but not essential, work may be carried out at room temperature. But, for example, very large, warehouse-type experimental facilities may lack sufficient heating and cooling capabilities to maintain 'room temperatures'.

If it is believed that work which may have some dependence upon temperature has been carried out at temperatures significantly outside the range 20 to 25 °C, it may be reported that it was carried out at an ambient temperature of some approximate specified value.

An assumed typical ambient temperature may be used for general calculations; for example, the thermal efficiency of a typical internal combustion engine may be given as approximately 25%, with no mention of the air temperature: the actual efficiency will depend to some extent on ambient temperature, decreasing in extremely hot weather conditions due to lower air density.

[edit] Ambient vs. room temperature

Being a less precise specification than even "room temperature", "ambient temperature" is more certain to be accurate. Because scientists strive for accuracy in their reports, many use this specification exclusively just as a matter of course, even to describe experiments that they could justifiably characterize as having been conducted at room temperature.

This is a nebulous issue, depending upon the language used. In many languages, for example Spanish, there is no expression for "room", as distinct from "ambient", temperature.

Arguably, no precision is lost in this practice: In disciplines where experimenters always work in laboratories, and where temperature differences of a few degrees make little difference with regard to the questions that scientists ask, the distinction between ambient and room temperature literally is not worth making. And, of course, the ambient temperature of a room is usually room temperature.

Yet small temperature differences have large effects on many natural processes. Therefore scientists who do observe a distinction between the two specifications may be sticklers about which one to apply. For example, heat given off by electronics or motors may warm the area around an experiment relative to the rest of a room. Under such circumstances, and depending on the question under investigation, some scientists would consider it inaccurate to report that an experiment took place at room temperature.

[edit] References


[edit] See also

da:Stuetemperatur de:Raumtemperatur et:Toatemperatuur es:Temperatura ambiente ko:실온 it:Temperatura ambiente nl:Kamertemperatuur no:Romtemperatur nds:Ruumtemperatur pl:Temperatura pokojowa pt:Temperatura ambiente sv:Rumstemperatur th:อุณหภูมิห้อง zh:常温

Room temperature

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