The diagram below shows the main features of a clinical thermometer. An instrument, a thermometer, is required to measure temperature objectively. It uses mercury as its thermometric substance and has a narrow constriction in the tube just above the bulb. Clinical thermometer simple english wikipedia, the free. Some substances have the property that changes with temperature. Thermometer types clinical thermometer, laboratory. There are many types of thermometers, but some common thermometers are laboratory thermometer, clinical thermometer, thermocouple, bimetallic strip thermometer, pyrometers, etc. The lengths of the mercury column of a mercury thermometer are 1.
Sensor types include resistance temperature detector rtd, thermocouple and thermistor. The relative change in resistance temperature coefficient. Thermometric substance is the material used in the thermometer, whose property varies with temperature thermometric property should vary linearly with temp over a reasonable range of temp the range of linearity of the. Some examples of such liquids are mercury and alcohol. The stem is plain front, enameled back, made of leadglass thermometric tubing 7 mm in diameter. Thermometric article about thermometric by the free. The clinical thermometer is a small tubular instrument of rather thick glass. An electrical signal from the infrared sensor is converted into the value of the. The way a digital thermometer works depends upon its type of sensor. A thermometer is a device that measures temperature or a temperature gradient. An infrared sensor senses infrared radiation incident through an opening portion for narrowing the angle of the field of view of the infrared sensor.
A clinical thermometer is a thermometer used to measure human body temperature. Get a printable copy pdf file of the complete article 521k, or click on a page image below to browse page by page. What is the purpose of the constriction in the clinical. Mercury in glass thermometer safety data sheet effective.
What are the advantages and disadvantages of the following. For the construction of a thermometer, one of the essential requirements is a thermometric substance which a. Modification of the thermometer suitable for recording temperature to the stem based upon a constant fractional increase in volume of thermometric substance above a defined fixed reference freezing point constitutes his contribution to clinical thermometry. The upper end was left open so that readings were influenced by evaporation but to a lesser extent atmospheric pressure. Get free shipping, cash on delivery and the best offers. Various liquids were used as thermometric substances, such as alcohol spirit of wine, linseed oil, and mercury. A clinical thermometer is an instrument used to measure the temperature of a human body. The boiling point of water or condensing point of steam is 100 o c or 212 o f or 373 k. The mercury thread needs to be shaken back into the bulb before the thermometer is used again. A gas thermometer determines the temperature based on the difference in pressure or volume of gas it is filled with. This helps for examle when one wants to know the body temperature of a patient heshe puts the thermometer in the suitable place to take the reading for sometime and then retrieves it to take the reading now the constriction prevents the thermometric substance from running back into the bulb so. Carl reinhold august wunderlich and the evolution of clinical thermometry authors. The first physician that put thermometer measurements to clinical practice was.
Thermometric requirements vary with the treatment modality and clinical situation. Thermometric liquids are those that are used in thermometers. They are accurate and sensitive, having a narrow place where the mercury level rises very fast. In 1641, grand duke ferdinand ii of tuscany, one of. Common rtd sensing elements constructed of platinum, copper or nickel have a repeatable resistance versus temperature relationship r vs t and operating temperature range. Carl reinhold august wunderlich and the evolution of. Gas thermometer definition is a thermometer containing gas as hydrogen as the enclosed thermometric substance, variations in temperature being indicated by the change in pressure of a fixed quantity of gas required to maintain the gas at a constant volume or the change in volume of a fixed quantity of gas maintained at a constant pressure. Digital thermometers measure the temperature by means of an electronic circuit.
Thermometry is the science and practice of temperature measurement. It is a long narrow glass tube with a bulb containing mercury at the end. Hero of alexandria 1070 ad knew of the principle that certain substances. It can determine the temperature of a body or even of air or atmosphere. The freezing point of water or melting point of ice is 0 o c or 32 o f or 273 k. The liquid in glass thermometer is most common one. The substance should have considerable variation over the small increase in temperature. Clinical thermometers a thermometer specially designed for measuring the temperature of the human body. Easy to clean and operate, the screen and value sizes are large and easy to read and measurements are given within seconds. Sensitivity, linearity, responsiveness of clinical thermometers are the same as that of laboratory thermometers.
A mercuryinglass thermometer and details of a clinical thermometer. In a clinical thermometer as in claim 1 wherein said thermometric material consists of a mixture of eicosane, heneicosane and docosane. A single use, disposable clinical thermometer for measuring temperatures within the range of clinical interest which comprises. Buy digital thermometer, clinical thermometer, infrared thermometer, analog thermometer online at smart medical buyer. Different types of thermometers and their uses updated. Electrical thermometer digital thermometer gas thermometer the main difference between them is in the property of the. The r vs t relationship is defined as the amount of resistance change of the sensor per degree of temperature change. Clinical thermometer definition is a thermometer for measuring body temperature that has a constriction in the tube above the bulb preventing movement of the column of liquid downward once it has reached its maximum temperature so that it continues to indicate the maximum temperature until the liquid is shaken back down into the bulb.
The property of a thermometric substance changes with temperature. Range for vaporpressure thermometry of various gases. The thermometer makes use of a physical property of a thermometric. It measures temperature in the range of 5 c to 110 c and on higher temperatures. Notes on types of thermometer according to construction. Digital thermometers are temperaturesensing instruments that are easily portable, have permanent probes, and a convenient digital display. Below are some of the advantages and disadvantages associated with thermometric liquids.
Clinical thermometer definition of clinical thermometer. Clinical thermometer is a slight modification of mercury thermometer. A thermometer or other device for measuring temperatures within a preselected range which utilizes, as a temperature indicating means, a solid, heat expansible substance which melts and expands continuously over the range. It is specially designed to measure the human body temperature. Thermometric property of a substance whose value changes with temperature e. Imp definitions the physical property on which a particular thermometer is based is called the thermometric property.
It is an ordinary mercury thermometer with two modifications. The reading is recorded within seconds, some having a red light or other device to indicate when maximum temperature is reached. Gas thermometer can be filled with any gas, but the most popular option is hydrogen. Thermometers a thermometer is an instrument used for measuring temperature. Temperatures on celsius and fahrenheit thermometers related to temperature ranges. A kink in the tube stops the mercury level from falling on its own. It is used to measure the room temperature of hot solids and liquids in experiments. The temperature range that is typically marked on a laboratory thermometer is. It prevents the thermometric substance mercury or alcohol from running back into the bulb. This is the temperature of pure melting ice at a pressure of one standard. A maximum thermometer is a mercury thermometer used to measure the.
Thermometric definition of thermometric by the free. The branch of physics or heat relating to the measurement of the temperature of a body is called thermometry. Divide the temperature range between the two fixed points into equal divisions. A clinical thermometer for measuring the temperature of a living body in a noncontacting manner by receiving infrared radiation from an eardrum or a body surface. It is a good conductor of heat and therefore the whole liquid reaches the temperature of the surroundings quickly. A thermometer is used to measure temperature using a change in a thermometric from me 200 at purdue university. Gas thermometer definition of gas thermometer by merriam. Digital thermometers selection guide engineering360.
The thermometer makes use of a physical property of a thermometric substance which changes continuously with temperature. The two liquids used in liquid in glass thermometers are mercury and alcohol. This constriction prevents the mercury from contracting and flowing back when it is removed from human body temperature of surroundings being lower. These temperatures are typically used in the calibration of thermometers and are known as. A thermometer is used to measure temperature using a. The thermometric fluid used by galileo galilei in his thermometer was air. The thermometer which is used to measure the temperature of a human body and has mercury as the thermometric substance is called clinical thermometer. There are constant pressure and constant volume gas thermometers.
In a clinical thermometer as in claim 1 wherein said diaphragm comprises a compressible transparent hose within said bulb, said capillary tube comprising an extension of said hose. Mercury in glass thermometer safety data sheet effective date. Thermometer definition of thermometer by medical dictionary. The following are some essential conditions governing choice of properties and materials for temperature measurement by the thermometer. Clinical thermometers are meant for clinical purposes. A thermometer is an instrument used to measures the temperature of a body. It is developed for measuring the human body temperature. Identification of the substancemixture and of the manufacturer chemical name. The extremely fine tube narrow bore of a thermometer is called a capillary. Most made in the 20th century are mercuryinglass thermometers. Explain how a physical property of a substance which varies with temperature may be used for the measurement of temperature.
Mercury in glass thermometer recommended uses of the chemicalproduct. The clinical thermometer, with a limited scale around body temperature, the maximum andor minimum thermometer, recording the maximum day temperature and minimum night temperature, and the beckman thermometer, which is used only in accurate measurement of temperature change, and has no fixed points, are particular types of liquidinglass. Preferred form is an inexpensive singleuse disposable clinical thermometer with a plastic casing and a solid indicating means e. Thermometer is the device used to measure temperature. A thermometer is a device that is used to measure the temperature of a body. In 1631, when french physician jean rey developed further a water thermometer he initiated the search for the ideal thermometric substance. This range is centered around the normal body temperature of 36. The adcm1 is a clinical grade digital thermometer designed for years of use. Autooff features ensure that the unit conserves power when not in use, and the thermometer is calibrated out of the box to be used for oral. Difference between alcohol and mercury thermometers. Full text full text is available as a scanned copy of the original print version.
Pdf the thermometerfrom the feeling to the instrument. Temperatures on celsius and fahrenheit thermometers related to temperature. Early evolution of the thermometer and application to. Thermometry thermometry is the science and practice of temperature measurement. Evolution of the thermometer a thermometer is a device that gauges temperature by measuring a temperaturedependent property, such as the expansion of a liquid in a sealed tube.