INTRODUCTION
You all are familiar with thermometer which is causally looking device used in our and in clinical even professional surgeon also used this device. This device need disinfecting after every use and we Have to be very careful while handling these. Have you ever thought a simple looking temperature measuring instrumentYeah and such a great history which is approximately 300 years old all invention of such device took more than 100 years history of a thermometer is unimaginable many scientists work on thermometer even after invasion lots of researchers are doneto diagnosis of disease with the help of temperature. Even now skin censors are available in market which is need of this pandemic period. Evolution of thermometer is not stopped here, thermometer is becoming advance day by day. So it’s become important for us to know the history and advancement of thermometer.
1. HISTORY
1.1 METHOD OF TEMPERATURE MEASURE BEFORE INVENTION OF THERMOMETER
In 1600 Galen gives then concept of neutral heat that define as neither heat nor cold and this was achieved by mixing ice at Celsius and water at Celsius in equal amounts so that person having hot hands feel cold and cold hands feels hot. Even melting point of butter is also used as high point by one scientist. Carl Renal Dini a member of academiadel Cimento and lecture in Padua used the freezing and melting point of ice in 1694. some scientist also check pulse for measure change in temperature of body. Galileo and Sanctorius used pendulum to measure pulse rate. (1)
1.2 FIRST STEP TOWARDS THERMOMETER
The era of measuring temperature changed by invention of air thermoscope. Air thermoscope was invented by Galileo around 1592, it consist of a stem having glass round bulb at one end and open at other end. When he rubbed the bulb by his hand with stem dipped in water such that air expelled from the stem into water. The disadvantage of Air thermometer of Galileo was that it affected by barometric pressure and the height of column depend upon temperature of the bulb and atmospheric pressure outside the thermometer.(1,2,3)
Santorius the colleague of Galileo and Italian professor made crude thermometer from air thermometer of Galileo. He added glass beads and placed them at regular interval on the stem and also closed stem from other end. Later in his commentarial in Primam fen primi libri canonis Avicenna he noted that the constitution affected by both body weight and body heat. He also give many design of thermometer but all take long time to measure oraltemperature even to get stable reading almost took 8mins and for this duration glass of thermometer must be in contact with sublingual tissue.(1,3)
Around 1654 Florentine academy of Italy developed a model in which stem is closed and spirit of wine was used in bulb which substituted air in bulb. when wine is heated through the glass bulb so wine is rise in stem and on cooling it falls again. And glass beasts are also on the stem which melts and freeze according to temperature raise in wine. This device is beautifully designed and delicate but have a limitation that is accuracy, this device is not that much accurate because no scale is present in it.(1)
Francisco Boulliau member of Academia Del Cimento in 1659, also substitute mercury with wine but not accurate results were obtained due to absence of scale.
In 1665 a scale in centigrade system extended from freezing point to the boiling point of water added by Christian Huygens.
1.3 INVENTION OF MERCURY THERMOMETER
In 1709 GabrielFahrenheit introduced an first accurate temperature measuring device whose modified version used today. Fahrenheit firstly male alcohol based thermometer and he developed his own scale which were based on scale that suggested by Isaac newton and later on he found the way to purify mercury and used it in place of alcohol. Fahrenheit thermometer has highest reading of f and record normal body temperature as f.(1,4)
Carl Reinhold august Wunderlich was a German physician and medical professor who done great researches on thermometry. he worked around 15 years and observed the temperature of 100,000 people by using normal whether thermometer and published his findings. His work mainly based on following principles:
Normal temperature range of human body that he found as 98•6°-100•4°
Average daily variation in temperature.
Variation of temperature in disease so that identification of disease become easy.(5)
1.4 IS MERCURY THERMOMETER IS SAFE?
After this research instrument of medical thermometer convert in clinical thermometer as a universally accepted tool.From past decades we used mercury thermometer in hospitals and also in home, it is easily available accurate and cheap . But mercury thermometer had his own disadvantage mercury Is toxic in nature and mercury glass thermometer is easily broke while using , on breaking and splitting of mercury on floor form a small droplets which even not clearly visible and this drops emit toxic vapour which are inhaled or absorbed by mercury. Even mercury inhaled by child can cause brain damage and adults re subtle suspicion is not easily aroused. And poor correlation between tissue and blood or urine concentration makes detection difficult. So now days mercury thermometer replaced by digital thermometer.(6)
2. EVOLUTION
2.1 DIGITAL THERMOMETER
Digital thermometers are invented by Mueller, B. Martin, R. Martin, and J. Chandler in 1973. This instrument is basically based on semiconductor and capable of interfacing to a micro computingfor data-processing. It can measure temperature within range of -to + Celsius. These instruments have accuracy of Celsius. This temperature are not expensive and easy to use.(7)
2.2 INFRARED THERMOMETER
Today thermometer become more advanced from past 1.5 years we are using Infrared thermometer. Infrared thermometer measure temperature of body with out being in contact with that body. They are safe to use special during this pandemic period. They also help us to measure surface temperature which we can’t measure with the help of Mercury Or digital thermometer. Even we can discover thermal footprint with the help infrared thermometer.
Temperature measurements byinfrared thermometer basically involved four steps that are following:-
Electromagnetic radiation emit by object.
Radiation determine by temperature
Radiation transport energy
Reaction of sensor on this energy.(8)
CONCLUSION
From 1 00 scientist were engaged in development of thermometer. Galileo invented air thermometer after that Sanctorius developed crude thermometer which takes long time and does not have high accuracy that is because of absence of scale. In 1700 thermometer got evolved, Fahrenheit developed mercury which is more accurate and take less time to measure which become in general use when Wunderlich represents his research. But mercury thermometer is not safe and does not have vast temperature range which accomplished by digital thermometer. Digital thermometer are safe, accurate and gives reading in seconds but not useful to take surface reading which taken by infrared thermometer and today, they are in general use because they can measure temperature from distance which were useful to maintain pandemic guidelines.
REFRENCES
1. KEEZER,WILLIAM.S, the clinical thermometer, 1996, page -1,2.
2. J.M.S.PEARCE, a brief history of the clinical thermometer, 2002, page -1, 2.
3. B.NOYES, the history of the thermometer and the sphygmomanometer, 1936, page-1, 2.
4. D.kARWATAKA, Gabriel Fahrenheit and Andres Celsius and their temperature scale, 2017,page-1
5. J.S. HALLER, Jr. PHD, B. LONG, medical thermometry– a short history, 1985,page-1, 5-7.
6. R.R, O. OLDHAMN , should we use mercury thermometer, 1992, page 1-2.
7. I.C.D HADLEY AND R.D.GOULD, inexpensive digital thermometer for measurements and semiconductors, 1991,page-2, 8.
8. R. GIRWIDZ and I. GREN, the infrared thermometer in school sciences, 2011,page-1-4, 6.
By Shalley Jain
shalleyjain24@gmail.com
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