|
Thermometer
A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). 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 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, and in scientific research. History 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 is an absolute thermodynamic temperature scale. Internationally agreed temperature scales are designed to approximate this clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury-in-glass Thermometer
The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. The space above the mercury may be filled with nitrogen gas or it may be at less than atmospheric pressure, a partial vacuum. In order to calibrate the thermometer, the bulb is made to reach thermal equilibrium with a temperature standard such as an ice/water mixture, and then with another standard such as water/vapour, and the tube is divided into regular intervals between the fixed points. In principle, thermometers made of different material (e.g., coloured alcohol thermometers) might be expected to give different intermediate readings due to diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Thermometer
An infrared thermometer is a thermometer which infers temperature from a portion of the thermal radiation sometimes called black-body radiation emitted by the object being measured. They are sometimes called laser thermometers as a laser is used to help aim the thermometer, or non-contact thermometers or temperature guns, to describe the device's ability to measure temperature from a distance. By knowing the amount of infrared energy emitted by the object and its emissivity, the object's temperature can often be determined within a certain range of its actual temperature. Infrared thermometers are a subset of devices known as "thermal radiation thermometers". Sometimes, especially near ambient temperatures, readings may be subject to error due to the reflection of radiation from a hotter body—even the person holding the instrument — rather than radiated by the object being measured, and to an incorrectly assumed emissivity. The design essentially consists of a lens to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature Measurement
Temperature measurement (also known as thermometry) describes the process of measuring a current local temperature for immediate or later evaluation. Datasets consisting of repeated standardized measurements can be used to assess temperature trends. History Attempts at standardized temperature measurement prior to the 17th century were crude at best. For instance in 170 AD, physician Claudius Galenus mixed equal portions of ice and boiling water to create a "neutral" temperature standard. The modern scientific field has its origins in the works by Florentine scientists in the 1600s including Galileo constructing devices able to measure relative change in temperature, but subject also to confounding with atmospheric pressure changes. These early devices were called thermoscopes. The first sealed thermometer was constructed in 1654 by the Grand Duke of Toscani, Ferdinand II. The development of today's thermometers and temperature scales began in the early 18th century, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Temperature And Pressure Measurement Technology
Timeline of temperature and pressure measurement technology. A history of temperature measurement and pressure measurement technology. Timeline 1500s * 1592–1593 — Galileo Galilei builds a device showing variation of hotness known as the thermoscope using the contraction of air to draw water up a tube. 1600s * 1612 — Santorio Sanctorius makes the first thermometer for medical use * 1617 — Giuseppe Biancani published the first clear diagram of a thermoscope * 1624 — The word thermometer (in its French form) first appeared in ''La Récréation Mathématique'' by Jean Leurechon, who describes one with a scale of 8 degrees.R. P. Benedict (1984) ''Fundamentals of Temperature, Pressure, and Flow Measurements'', 3rd ed., , p. 4 * 1629 — Joseph Solomon Delmedigo describes in a book an accurate sealed-glass thermometer that uses brandy * 1638 — Robert Fludd the first thermoscope showing a scale and thus constituting a thermometer. * 1643 — Evangelista Torricelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Temperature Scale Of 1990
The International Temperature Scale of 1990 (ITS-90) is an equipment calibration standard specified by the International Committee of Weights and Measures (CIPM) for making measurements on the Kelvin and Celsius temperature scales. It is an approximation of thermodynamic temperature that facilitates the comparability and compatibility of temperature measurements internationally. It defines fourteen calibration points ranging from to ( to ) and is subdivided into multiple temperature ranges which overlap in some instances. ITS-90 is the most recent of a series of International Temperature Scales adopted by the CIPM since 1927. Adopted at the 1989 General Conference on Weights and Measures, it supersedes the International Practical Temperature Scale of 1968 (amended edition of 1975) and the 1976 "Provisional 0.5 K to 30 K Temperature Scale". The CCT has also published several online guidebooks to aid realisations of the ITS-90. The lowest temperature covered by the ITS-90 is 0. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Temperature
Thermodynamic temperature is a quantity defined in thermodynamics as distinct from kinetic theory or statistical mechanics. Historically, thermodynamic temperature was defined by Kelvin in terms of a macroscopic relation between thermodynamic work and heat transfer as defined in thermodynamics, but the kelvin was redefined by international agreement in 2019 in terms of phenomena that are now understood as manifestations of the kinetic energy of free motion of microscopic particles such as atoms, molecules, and electrons. From the thermodynamic viewpoint, for historical reasons, because of how it is defined and measured, this microscopic kinetic definition is regarded as an "empirical" temperature. It was adopted because in practice it can generally be measured more precisely than can Kelvin's thermodynamic temperature. A thermodynamic temperature reading of zero is of particular importance for the third law of thermodynamics. By convention, it is reported on the '' Kelvin sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Human Body Temperature
Normal human body-temperature (normothermia, euthermia) is the typical temperature range found in humans. The normal human body temperature range is typically stated as . Human body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the body the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by thermoregulation, in which adjustment of temperature is triggered by the central nervous system. Methods of measurement Taking a person's temperature is an initial part of a full clinical examination. There are various types of medical thermometers, as well as sites used for measurement, including: * In the rectum (rectal temperature) * In the mouth (oral temperature) * Under the arm (axillary temperature) * In the ear (tympanic temperature) * On the skin of the forehead over the temporal artery * Using heat fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joachim Dalencé
Joachim d'Alencé or Joachim Dalence (c. 1640 – 1707) was a French scientist known only from books on meteorological instruments. He was among the first to consider the use of two standards for graduating a thermometer scale. He is known largely for his two books ''Traitte de l'aiman'' (1687) on magnetism and ''Traittez des barometres, thermometres, et notiometres, au hygrometres'' (1688) on barometers, thermometers and hygrometers. D'Alencé's father, Martin, was a surgeon who influenced the creation of a position as a royal advisor in 1663. Joachim made a trip to England in 1668 where he obtained a telescope and became a friend of Henry Oldenburg. He later corresponded with Huygens and Leibniz. He is best remembered for his book describing thermometers and the system of graduating thermometers with two reference points - the freezing point of water and the melting point of butter. He suggested the use of a 3:1 mixture of water and nitric acid held in a bulb for the thermometer fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoscope
A thermoscope is a device that shows changes in temperature. A typical design is a tube in which a liquid rises and falls as the temperature changes. The modern thermometer gradually evolved from it with the addition of a scale in the early 17th century and standardisation throughout the 17th and 18th centuries. Function Devices employing both heat and pressure were common during Galileo's time, used for fountains, nursing, or bleeding in medicine. The device was built from a small vase filled with water, attached to a thin vertically rising pipe, with a large empty glass ball at the top. Changes in temperature of the upper ball would exert positive or negative pressure on the water below, causing it to rise or lower in the thin column. The device established fixed points but does not measure specific quantity, although it can tell when something is warmer than another thing. Essentially, thermoscopes served as a justification of sorts regarding what is observed or experienced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferdinando II De' Medici, Grand Duke Of Tuscany
Ferdinando II de' Medici (14 July 1610 – 23 May 1670) was grand duke of Tuscany from 1621 to 1670. He was the eldest son of Cosimo II de' Medici and Maria Maddalena of Austria. He was remembered by his contemporaries as a man of culture and science, actively participating in the Accademia del Cimento, the first scientific society in Italy, formed by his younger brother, Leopoldo de' Medici. His 49-year rule was punctuated by the beginning of Tuscany's long economic decline, which was further exacerbated by his successor, Cosimo III de' Medici. He married Vittoria della Rovere, a first cousin, with whom he had two children who reached adulthood: the aforementioned Cosimo III, and Francesco Maria de' Medici, Duke of Rovere and Montefeltro, a cardinal. Reign Ferdinando was only 10 years of age when his father Cosimo II died. Because he had not yet reached maturity, his mother Maria Maddalena and paternal grandmother, Christina of Lorraine, acted as joint regents. His tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barometer
A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, pressure systems and frontal boundaries. Barometers and pressure altimeters (the most basic and common type of altimeter) are essentially the same instrument, but used for different purposes. An altimeter is intended to be used at different levels matching the corresponding atmospheric pressure to the altitude, while a barometer is kept at the same level and measures subtle pressure changes caused by weather and elements of weather. The average atmospheric pressure on the earth's surface varies between 940 and 1040 hPa (mbar). The average atmospheric pressure at sea level is 1013 hPa (mbar). Etymology The word '' barometer'' is derived from the Ancient Greek (), meaning "weight", and (), meaning "me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensible Heat
Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system, and some macroscopic variables of the body or system, but leaves unchanged certain other macroscopic variables of the body or system, such as volume or pressure. Usage The term is used in contrast to a latent heat, which is the amount of heat exchanged that is hidden, meaning it occurs without change of temperature. For example, during a phase change such as the melting of ice, the temperature of the system containing the ice and the liquid is constant until all ice has melted. The terms latent and sensible are correlative. The sensible heat of a thermodynamic process may be calculated as the product of the body's mass (''m'') with its specific heat capacity (''c'') and the change in temperature (\Delta T): : Q_ = m c \Delta T \, . ''Sensible heat'' and ''latent heat'' are not special forms of energy. Rather, they describe exchanges of h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
