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77-641: ATOC may refer to: Acoustic thermometry Amgen Tour of California , a cycling race A Touch of Cloth , a British TV comedy series Rail Delivery Group , formerly the Association of Train Operating Companies, in the United Kingdom See also [ edit ] Atoc , an Inca general Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

154-425: A platinum resistance thermometer, so these two will disagree slightly at around 50 °C. There may be other causes due to imperfections in the instrument, e.g. in a liquid-in-glass thermometer if the capillary tube varies in diameter. For many purposes reproducibility is important. That is, does the same thermometer give the same reading for the same temperature (or do replacement or multiple thermometers give

231-559: A temperature scale which now (slightly adjusted) bears his name . In 1742, Anders Celsius (1701–1744) proposed a scale with zero at the boiling point and 100 degrees at the freezing point of water, though the scale which now bears his name has them the other way around. French entomologist René Antoine Ferchault de Réaumur invented an alcohol thermometer and, temperature scale in 1730, that ultimately proved to be less reliable than Fahrenheit's mercury thermometer. The first physician to use thermometer measurements in clinical practice

308-414: A closed system, the final state of the system is never colder than the initial state; except for phase changes with latent heat, it is hotter than the initial state. There are several principles on which empirical thermometers are built, as listed in the section of this article entitled "Primary and secondary thermometers". Several such principles are essentially based on the constitutive relation between

385-447: A constant volume air thermometer. Constant volume thermometers do not provide a way to avoid the problem of anomalous behaviour like that of water at approximately 4 °C. Planck's law very accurately quantitatively describes the power spectral density of electromagnetic radiation, inside a rigid walled cavity in a body made of material that is completely opaque and poorly reflective, when it has reached thermodynamic equilibrium, as

462-534: A coordinate manifold of material behaviour. The points L {\displaystyle L} of the manifold M {\displaystyle M} are called 'hotness levels', and M {\displaystyle M} is called the 'universal hotness manifold'." To this information there needs to be added a sense of greater hotness; this sense can be had, independently of calorimetry , of thermodynamics , and of properties of particular materials, from Wien's displacement law of thermal radiation :

539-439: A digital display or input to a computer. Thermometers may be described as empirical or absolute. Absolute thermometers are calibrated numerically by the thermodynamic absolute temperature scale. Empirical thermometers are not in general necessarily in exact agreement with absolute thermometers as to their numerical scale readings, but to qualify as thermometers at all they must agree with absolute thermometers and with each other in

616-432: A function of absolute thermodynamic temperature alone. A small enough hole in the wall of the cavity emits near enough blackbody radiation of which the spectral radiance can be precisely measured. The walls of the cavity, provided they are completely opaque and poorly reflective, can be of any material indifferently. This provides a well-reproducible absolute thermometer over a very wide range of temperatures, able to measure

693-503: A half mile deep, hence marine mammals, which are bound to the surface, were generally further than a half mile from the source. The source level was modest, less than the sound level of large whales, and the duty cycle was 2% (i.e., the sound is on only 2% of the day). After six years of study the official, formal conclusion from this study was that the ATOC transmissions have "no biologically significant effects". Other acoustics activities in

770-399: A medically accurate body temperature. Traditional thermometers were all non-registering thermometers. That is, the thermometer did not hold the temperature reading after it was moved to a place with a different temperature. Determining the temperature of a pot of hot liquid required the user to leave the thermometer in the hot liquid until after reading it. If the non-registering thermometer

847-476: A numerical value (e.g. the visible scale that is marked on a mercury-in-glass thermometer or the digital readout on an infrared model). Thermometers are widely used in technology and industry to monitor processes, in meteorology , in medicine ( medical thermometer ), and in scientific research. While an individual thermometer is able to measure degrees of hotness, the readings on two thermometers cannot be compared unless they conform to an agreed scale. Today there

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924-458: A particular travel time. The multiple travel times measure the sound speed averaged over each of the multiple acoustic paths. These measurements make it possible to infer aspects of the structure of temperature or current variations as a function of depth. The solution for sound speed, hence temperature, from the acoustic travel times is an inverse problem . Ocean acoustic tomography integrates temperature variations over large distances, that is,

1001-405: A platinum resistance thermometer with a digital display to 0.1 °C (its precision) which has been calibrated at 5 points against national standards (−18, 0, 40, 70, 100 °C) and which is certified to an accuracy of ±0.2 °C. According to British Standards , correctly calibrated, used and maintained liquid-in-glass thermometers can achieve a measurement uncertainty of ±0.01 °C in

1078-418: A receiver. The slight differences in travel time between the reciprocally-traveling signals are used to measure ocean currents , since the reciprocal signals travel with and against the current. The average of these reciprocal travel times is the measure of temperature, with the small effects from ocean currents entirely removed. Ocean temperatures are inferred from the sum of reciprocal travel times, while

1155-524: A recipe for building a "Fountain which trickles by the Action of the Sun's Rays," a more elaborate version of Philo's pneumatic experiment but which worked on the same principle of heating and cooling air to move water around. Translations of the ancient work Pneumatics were introduced to late 16th century Italy and studied by many, including Galileo Galilei , who had read it by 1594. The Roman Greek physician Galen

1232-504: A scale of 8 degrees. The word comes from the Greek words θερμός , thermos , meaning "hot" and μέτρον, metron , meaning "measure". The above instruments suffered from the disadvantage that they were also barometers , i.e. sensitive to air pressure. In 1629, Joseph Solomon Delmedigo , a student of Galileo and Santorio in Padua, published what is apparently the first description and illustration of

1309-426: A sealed liquid-in-glass thermometer. It is described as having a bulb at the bottom of a sealed tube partially filled with brandy. The tube had a numbered scale. Delmedigo did not claim to have invented this instrument. Nor did he name anyone else as its inventor. In about 1654, Ferdinando II de' Medici, Grand Duke of Tuscany (1610–1670) did produce such an instrument, the first modern-style thermometer, dependent on

1386-418: A single transmitted acoustic signal, this set of rays gives rise to multiple arrivals at the receiver, the travel time of each arrival corresponding to a particular ray path. The earliest arrivals correspond to the deeper-traveling rays, since these rays travel where sound speed is greatest. The ray paths are easily calculated using computers (" ray tracing "), and each ray path can generally be identified with

1463-435: A thermometric material must have three properties: (1) Its heating and cooling must be rapid. That is to say, when a quantity of heat enters or leaves a body of the material, the material must expand or contract to its final volume or reach its final pressure and must reach its final temperature with practically no delay; some of the heat that enters can be considered to change the volume of the body at constant temperature, and

1540-403: A thermoscope and a thermometer is that the latter has a scale. A thermometer is simply a thermoscope with a scale. ... I propose to regard it as axiomatic that a “meter” must have a scale or something equivalent. ... If this is admitted, the problem of the invention of the thermometer becomes more straightforward; that of the invention of the thermoscope remains as obscure as ever. Given this,

1617-463: A universality character of thermodynamic equilibrium, that it has the universal property of producing blackbody radiation. There are various kinds of empirical thermometer based on material properties. Many empirical thermometers rely on the constitutive relation between pressure, volume and temperature of their thermometric material. For example, mercury expands when heated. If it is used for its relation between pressure and volume and temperature,

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1694-488: A wide range of spatial scales. Indeed, tomography has been contemplated as a measurement of ocean climate using transmissions over antipodal distances. Tomography has come to be a valuable method of ocean observation, exploiting the characteristics of long-range acoustic propagation to obtain synoptic measurements of average ocean temperature or current. One of the earliest applications of tomography in ocean observation occurred in 1988-9. A collaboration between groups at

1771-432: Is a device that measures temperature (the hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer or the pyrometric sensor in an infrared thermometer ) in which some change occurs with a change in temperature; and (2) some means of converting this change into

1848-466: Is a fundamental character of temperature and thermometers. As it is customarily stated in textbooks, taken alone, the so-called " zeroth law of thermodynamics " fails to deliver this information, but the statement of the zeroth law of thermodynamics by James Serrin in 1977, though rather mathematically abstract, is more informative for thermometry: "Zeroth Law – There exists a topological line M {\displaystyle M} which serves as

1925-423: Is an electrical conductor , so the oceans are opaque to electromagnetic energy (e.g., light or radar ). The oceans are fairly transparent to low-frequency acoustics, however. The oceans conduct sound very efficiently, particularly sound at low frequencies, i.e., less than a few hundred hertz. These properties motivated Walter Munk and Carl Wunsch to suggest "acoustic tomography" for ocean measurement in

2002-552: Is an absolute thermodynamic temperature scale. Internationally agreed temperature scales are designed to approximate this closely, based on fixed points and interpolating thermometers. The most recent official temperature scale is the International Temperature Scale of 1990 . It extends from 0.65  K (−272.5 °C; −458.5 °F) to approximately 1,358 K (1,085 °C; 1,985 °F). Sparse and conflicting historical records make it difficult to pinpoint

2079-404: Is called the latent heat of expansion at constant temperature ; and the rest of it can be considered to change the temperature of the body at constant volume, and is called the specific heat at constant volume . Some materials do not have this property, and take some time to distribute the heat between temperature and volume change. (2) Its heating and cooling must be reversible. That is to say,

2156-404: Is created, sucking liquid up into the tube. Any changes in the position of the liquid will now indicate whether the air in the sphere is getting hotter or colder. Translations of Philo's experiment from the original ancient Greek were utilized by Robert Fludd sometime around 1617 and used as the basis for his air thermometer. In his book, Pneumatics , Hero of Alexandria (10–70 AD) provides

2233-546: Is given credit for introducing two concepts important to the development of a scale of temperature and the eventual invention of the thermometer. First, he had the idea that hotness or coldness may be measured by "degrees of hot and cold." He also conceived of a fixed reference temperature, a mixture of equal amounts of ice and boiling water, with four degrees of heat above this point and four degrees of cold below. 16th century physician Johann Hasler developed body temperature scales based on Galen's theory of degrees to help him mix

2310-471: Is smaller than a micrometre , and new methods and materials have to be used. Nanothermometry is used in such cases. Nanothermometers are classified as luminescent thermometers (if they use light to measure temperature) and non-luminescent thermometers (systems where thermometric properties are not directly related to luminescence). Thermometers used specifically for low temperatures. Various thermometric techniques have been used throughout history such as

2387-653: The Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution deployed a six-element tomographic array in the abyssal plain of the Greenland Sea gyre to study deep water formation and the gyre circulation. Other applications include the measurement of ocean tides, and the estimation of ocean mesoscale dynamics by combining tomography, satellite altimetry, and in situ data with ocean dynamical models. In addition to

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2464-1046: The Woods Hole Oceanographic Institution , and Ted Birdsall and Kurt Metzger of the University of Michigan developed the use of sound to infer information about the ocean's large-scale temperatures, and in particular to attempt the detection of global warming in the ocean. This group transmitted sounds from Oahu that were recorded at about ten receivers stationed around the rim of the Pacific Ocean over distances of 4,000 km (2,500 mi). These experiments demonstrated that changes in temperature could be measured with an accuracy of about 20 millidegrees. Spiesberger et al. did not detect global warming. Instead they discovered that other natural climatic fluctuations, such as El Nino, were responsible in part for substantial fluctuations in temperature that may have masked any slower and smaller trends that may have occurred from global warming. The Acoustic Thermometry of Ocean Climate (ATOC) program

2541-456: The Renaissance period. In the 3rd century BC, Philo of Byzantium documented his experiment with a tube submerged in a container of liquid on one end and connected to an air-tight, hollow sphere on the other. When air in the sphere is heated with a candle or by exposing it to the sun, expanding air exits the sphere and generates bubbles in the vessel. As air in the sphere cools, a partial vacuum

2618-402: The absolute temperature of a body inside the cavity. A thermometer is called primary or secondary based on how the raw physical quantity it measures is mapped to a temperature. As summarized by Kauppinen et al., "For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities. Examples of these are thermometers based on

2695-429: The appropriate amount of medicine for patients. In the late 16th and early 17th centuries, several European scientists, notably Galileo Galilei and Italian physiologist Santorio Santorio developed devices with an air-filled glass bulb, connected to a tube, partially filled with water. As the air in the bulb warms or cools, the height of the column of water in the tube falls or rises, allowing an observer to compare

2772-403: The average temperature of ocean basins, therefore, the acoustic measurement is quite cost effective. Tomographic measurements also average variability over depth as well, since the ray paths cycle throughout the water column. "Reciprocal tomography" employs the simultaneous transmissions between two acoustic transceivers. A "transceiver" is an instrument incorporating both an acoustic source and

2849-415: The controversy were the extensive history of activism where marine mammals are concerned, stemming from the ongoing whaling conflict, and the sympathy that much of the public feels toward marine mammals. As a result of this controversy, the ATOC program conducted a $ 6 million study of the effects of the acoustic transmissions on a variety of marine mammals. The acoustic source was mounted on the bottom about

2926-402: The current height of the water to previous heights to detect relative changes of the heat in the bulb and its immediate environment. Such devices, with no scale for assigning a numerical value to the height of the liquid, are referred to as a thermoscope because they provide an observable indication of sensible heat (the modern concept of temperature was yet to arise). The difference between

3003-573: The currents are inferred from the difference of reciprocal travel times. Generally, ocean currents (typically 10 cm/s (3.9 in/s)) have a much smaller effect on travel times than sound speed variations (typically 5 m/s (16 ft/s)), so "one-way" tomography measures temperature to good approximation. In the ocean, large-scale temperature changes can occur over time intervals from minutes ( internal waves ) to decades (oceanic climate change ). Tomography has been employed to measure variability over this wide range of temporal scales and over

3080-560: The decade-long measurements obtained in the North Pacific, acoustic thermometry has been employed to measure temperature changes of the upper layers of the Arctic Ocean basins, which continues to be an area of active interest. Acoustic thermometry was also recently been used to determine changes to global-scale ocean temperatures using data from acoustic pulses sent from one end of the Earth to

3157-402: The deep ocean which is presently poorly sampled by in-situ instruments. The ATOC project was embroiled in issues concerning the effects of acoustics on marine mammals (e.g. whales , porpoises , sea lions , etc.). Public discussion was complicated by technical issues from a variety of disciplines ( physical oceanography , acoustics , marine mammal biology, etc.) that makes understanding

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3234-455: The defining points in the International Temperature Scale of 1990 , though in practice the melting point of water is more commonly used than its triple point, the latter being more difficult to manage and thus restricted to critical standard measurement. Nowadays manufacturers will often use a thermostat bath or solid block where the temperature is held constant relative to a calibrated thermometer. Other thermometers to be calibrated are put into

3311-434: The effects of acoustics on marine mammals difficult for the experts, let alone the general public. Many of the issues concerning acoustics in the ocean and their effects on marine mammals were unknown. Finally, there were a variety of public misconceptions initially, such as a confusion of the definition of sound levels in air vs. sound levels in water. If a given number of decibels in water are interpreted as decibels in air,

3388-446: The equation of state of a gas, on the velocity of sound in a gas, on the thermal noise voltage or current of an electrical resistor, and on the angular anisotropy of gamma ray emission of certain radioactive nuclei in a magnetic field ." In contrast, "Secondary thermometers are most widely used because of their convenience. Also, they are often much more sensitive than primary ones. For secondary thermometers knowledge of

3465-527: The expansion of a liquid and independent of air pressure. Many other scientists experimented with various liquids and designs of thermometer. However, each inventor and each thermometer was unique — there was no standard scale . Early attempts at standardization added a single reference point such as the freezing point of water. The use of two references for graduating the thermometer is said to have been introduced by Joachim Dalence in 1668, although Christiaan Huygens (1629–1695) in 1665 had already suggested

3542-562: The first showing a scale and thus constituting a thermometer was by Santorio Santorio in 1625. This was a vertical tube, closed by a bulb of air at the top, with the lower end opening into a vessel of water. The water level in the tube was controlled by the expansion and contraction of the air, so it was what we would now call an air thermometer. The word thermometer (in its French form) first appeared in 1624 in La Récréation Mathématique by Jean Leurechon , who describes one with

3619-421: The following way: given any two bodies isolated in their separate respective thermodynamic equilibrium states, all thermometers agree as to which of the two has the higher temperature, or that the two have equal temperatures. For any two empirical thermometers, this does not require that the relation between their numerical scale readings be linear, but it does require that relation to be strictly monotonic . This

3696-414: The highest or lowest temperature recorded until manually re-set, e.g., by shaking down a mercury-in-glass thermometer, or until an even more extreme temperature is experienced. Electronic registering thermometers may be designed to remember the highest or lowest temperature, or to remember whatever temperature was present at a specified point in time. Thermometers increasingly use electronic means to provide

3773-401: The invention of the thermometer to any single person or date with certitude. In addition, given the many parallel developments in the thermometer's history and its many gradual improvements over time, the instrument is best viewed not as a single invention, but an evolving technology . Early pneumatic devices and ideas from antiquity provided inspiration for the thermometer's invention during

3850-417: The late 1970s. The advantages of the acoustical approach to measuring temperature are twofold. First, large areas of the ocean's interior can be measured by remote sensing . Second, the technique naturally averages over the small scale fluctuations of temperature (i.e., noise) that dominate ocean variability. From its beginning, the idea of observations of the ocean by acoustics was married to estimation of

3927-433: The material must be able to be heated and cooled indefinitely often by the same increment and decrement of heat, and still return to its original pressure, volume and temperature every time. Some plastics do not have this property; (3) Its heating and cooling must be monotonic. That is to say, throughout the range of temperatures for which it is intended to work, At temperatures around about 4 °C, water does not have

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4004-478: The measured property is not sufficient to allow direct calculation of temperature. They have to be calibrated against a primary thermometer at least at one temperature or at a number of fixed temperatures. Such fixed points, for example, triple points and superconducting transitions, occur reproducibly at the same temperature." Thermometers can be calibrated either by comparing them with other calibrated thermometers or by checking them against known fixed points on

4081-632: The measured travel times result from the accumulated effects of all the temperature variations along the acoustic path, hence measurements by the technique are inherently averaging. This is an important, unique property, since the ubiquitous small-scale turbulent and internal-wave features of the ocean usually dominate the signals in measurements at single points. For example, measurements by thermometers (i.e., moored thermistors or Argo drifting floats) have to contend with this 1-2 °C noise, so that large numbers of instruments are required to obtain an accurate measure of average temperature. For measuring

4158-416: The nature of the acoustic signal (e.g., a sudden pulse, or coded sequence), depth of the sound source, directionality of the sound source, water depth and local topography, reverberation, etc. Tomographic transmissions consist of long coded signals (e.g., "m-sequences" ) lasting 30 seconds or more. The frequencies employed range from 50 to 1000 Hz and source powers range from 100 to 250 W, depending on

4235-441: The nearest 10 °C or more. Clinical thermometers and many electronic thermometers are usually readable to 0.1 °C. Special instruments can give readings to one thousandth of a degree. However, this precision does not mean the reading is true or accurate, it only means that very small changes can be observed. A thermometer calibrated to a known fixed point is accurate (i.e. gives a true reading) at that point. The invention of

4312-399: The ocean may not be so benign insofar as marine mammals are concerned. Various types of man-made sounds have been studied as potential threats to marine mammals, such as airgun shots for geophysical surveys, or transmissions by the U.S. Navy for various purposes. The actual threat depends on a variety of factors beyond noise levels: sound frequency, frequency and duration of transmissions,

4389-427: The ocean's state using modern numerical ocean models and the techniques assimilating data into numerical models. As the observational technique has matured, so too have the methods of data assimilation and the computing power required to perform those calculations. One of the intriguing aspects of tomography is that it exploits the fact that acoustic signals travel along a set of generally stable ray paths. From

4466-552: The other. Acoustic thermometry is an idea to observe the world's ocean basins, and the ocean climate in particular, using trans- basin acoustic transmissions . "Thermometry", rather than "tomography", has been used to indicate basin-scale or global scale measurements. Prototype measurements of temperature have been made in the North Pacific Basin and across the Arctic Basin . Starting in 1983, John Spiesberger of

4543-425: The particular goals of the measurements. With precise timing such as from GPS , travel times can be measured to a nominal accuracy of 1 millisecond. While these transmissions are audible near the source, beyond a range of several kilometers the signals are usually below ambient noise levels, requiring sophisticated spread-spectrum signal processing techniques to recover them. Thermometers A thermometer

4620-416: The possible inventors of the thermometer are usually considered to be Galileo, Santorio, Dutch inventor Cornelis Drebbel , or British mathematician Robert Fludd . Though Galileo is often said to be the inventor of the thermometer, there is no surviving document that he actually produced any such instrument. The first clear diagram of a thermoscope was published in 1617 by Giuseppe Biancani (1566 – 1624);

4697-568: The property (3), and is said to behave anomalously in this respect; thus water cannot be used as a material for this kind of thermometry for temperature ranges near 4 °C. Gases, on the other hand, all have the properties (1), (2), and (3)(a)(α) and (3)(b)(α). Consequently, they are suitable thermometric materials, and that is why they were important in the development of thermometry. According to Preston (1894/1904), Regnault found constant pressure air thermometers unsatisfactory, because they needed troublesome corrections. He therefore built

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4774-463: The range 0 to 100 °C, and a larger uncertainty outside this range: ±0.05 °C up to 200 or down to −40 °C, ±0.2 °C up to 450 or down to −80 °C. Thermometers utilize a range of physical effects to measure temperature. Temperature sensors are used in a wide variety of scientific and engineering applications, especially measurement systems. Temperature systems are primarily either electrical or mechanical, occasionally inseparable from

4851-464: The same bath or block and allowed to come to equilibrium, then the scale marked, or any deviation from the instrument scale recorded. For many modern devices calibration will be stating some value to be used in processing an electronic signal to convert it to a temperature. The precision or resolution of a thermometer is simply to what fraction of a degree it is possible to make a reading. For high temperature work it may only be possible to measure to

4928-411: The same reading)? Reproducible temperature measurement means that comparisons are valid in scientific experiments and industrial processes are consistent. Thus if the same type of thermometer is calibrated in the same way its readings will be valid even if it is slightly inaccurate compared to the absolute scale. An example of a reference thermometer used to check others to industrial standards would be

5005-461: The sound level will seem to be orders of magnitude larger than it really is - at one point the ATOC sound levels were erroneously interpreted as so loud the signals would kill 500,000 animals. The sound power employed, 250 W, was comparable those made by blue or fin whales, although those whales vocalize at much lower frequencies. The ocean carries sound so efficiently that sounds do not have to be that loud to cross ocean basins. Other factors in

5082-405: The state of a suitably selected particular material and its temperature. Only some materials are suitable for this purpose, and they may be considered as "thermometric materials". Radiometric thermometry, in contrast, can be only slightly dependent on the constitutive relations of materials. In a sense then, radiometric thermometry might be thought of as "universal". This is because it rests mainly on

5159-568: The system which they control (as in the case of a mercury-in-glass thermometer). Thermometers are used in roadways in cold weather climates to help determine if icing conditions exist. Indoors, thermistors are used in climate control systems such as air conditioners , freezers, heaters , refrigerators , and water heaters . Galileo thermometers are used to measure indoor air temperature, due to their limited measurement range. Such liquid crystal thermometers (which use thermochromic liquid crystals) are also used in mood rings and used to measure

5236-400: The technology to measure temperature led to the creation of scales of temperature . In between fixed calibration points, interpolation is used, usually linear. This may give significant differences between different types of thermometer at points far away from the fixed points. For example, the expansion of mercury in a glass thermometer is slightly different from the change in resistance of

5313-428: The temperature of a bath of thermal radiation is proportional , by a universal constant, to the frequency of the maximum of its frequency spectrum ; this frequency is always positive, but can have values that tend to zero . Another way of identifying hotter as opposed to colder conditions is supplied by Planck's principle , that when a process of isochoric adiabatic work is the sole means of change of internal energy of

5390-408: The temperature of water in fish tanks. Fiber Bragg grating temperature sensors are used in nuclear power facilities to monitor reactor core temperatures and avoid the possibility of nuclear meltdowns . Nanothermometry is an emergent research field dealing with the knowledge of temperature in the sub-micrometric scale. Conventional thermometers cannot measure the temperature of an object which

5467-407: The temperature scale. The best known of these fixed points are the melting and boiling points of pure water. (Note that the boiling point of water varies with pressure, so this must be controlled.) The traditional way of putting a scale on a liquid-in-glass or liquid-in-metal thermometer was in three stages: Other fixed points used in the past are the body temperature (of a healthy adult male) which

5544-456: The title ATOC . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=ATOC&oldid=874325991 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Acoustic thermometry Seawater

5621-492: The use of graduations based on the melting and boiling points of water as standards and, in 1694, Carlo Renaldini (1615–1698) proposed using them as fixed points along a universal scale. In 1701, Isaac Newton (1642–1726/27) proposed a scale of 12 degrees between the melting point of ice and body temperature . In 1714, scientist and inventor Daniel Gabriel Fahrenheit invented a reliable thermometer, using mercury instead of alcohol and water mixtures . In 1724, he proposed

5698-476: Was Herman Boerhaave (1668–1738). In 1866, Sir Thomas Clifford Allbutt (1836–1925) invented a clinical thermometer that produced a body temperature reading in five minutes as opposed to twenty. In 1999, Dr. Francesco Pompei of the Exergen Corporation introduced the world's first temporal artery thermometer, a non-invasive temperature sensor which scans the forehead in about two seconds and provides

5775-768: Was implemented in the North Pacific Ocean, with acoustic transmissions from 1996 through fall 2006. The measurements terminated when agreed-upon environmental protocols ended. The decade-long deployment of the acoustic source showed that the observations are sustainable on even a modest budget. The transmissions have been verified to provide an accurate measurement of ocean temperature on the acoustic paths, with uncertainties that are far smaller than any other approach to ocean temperature measurement. Repeating earthquakes acting as naturally-occurring acoustic sources have also been used in acoustic thermometry, which may be particularly useful for inferring temperature variability in

5852-525: Was originally used by Fahrenheit as his upper fixed point (96 °F (35.6 °C) to be a number divisible by 12) and the lowest temperature given by a mixture of salt and ice, which was originally the definition of 0 °F (−17.8 °C). (This is an example of a frigorific mixture .) As body temperature varies, the Fahrenheit scale was later changed to use an upper fixed point of boiling water at 212 °F (100 °C). These have now been replaced by

5929-420: Was removed from the hot liquid, then the temperature indicated on the thermometer would immediately begin changing to reflect the temperature of its new conditions (in this case, the air temperature). Registering thermometers are designed to hold the temperature indefinitely, so that the thermometer can be removed and read at a later time or in a more convenient place. Mechanical registering thermometers hold either

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