Fayl Faylin tarixcesi Faylin istifadesi Faylin qlobal istifadesi MetamelumatlarBu SVG faylin PNG formatindaki bu gorunusunun olcusu 645 600 piksel Diger olculer 258 240 piksel 516 480 piksel 826 768 piksel 1 101 1 024 piksel 2 202 2 048 piksel 960 893 piksel Faylin orijinali SVG fayli nominal olaraq 960 893 piksel faylin olcusu 329 KB Bu fayl Vikianbarda yerlesir Aciqlama sehifesindeki melumatlar asagida gosterilib Vikianbar azad lisenziyali media anbaridir Siz de tohfe vere bilersiniz Xulase IzahTyndalls setup for measuring radiant heat absorption by gases annotated svg English Illustration of John Tyndall s setup for measuring the radiant heat absorption of gases This illustration dates from 1861 and it is taken from one of John Tyndall s presentations where he describes his setup for measuring the relative radiant heat absorption of gases and vapors The galvanometer quantifies the difference in temperature between the left and right sides of the thermopile The reading on the galvanometer is settable to zero by moving the Heat Screen a bit closer or farther from the lefthand heat source That is the only role for the heat source on the left The heat source on the righthand side directs radiant heat into the long brass tube The long brass tube is highly polished on the inside which makes it a good reflector and non absorber of the radiant heat inside the tube Rock salt NaCl is practically transparent to radiant heat and so plugging the ends of the long brass tube with rock salt plates allows radiant heat to move freely in and out at the tube endpoints yet completely blocks the gas within from moving out To begin the measurements both heat sources are turned on the long brass tube is evacuated as much as possible with an air suction pump the galvanometer is set to zero and then the gas under study is released into the long brass tube The galvanometer is looked at again The extent to which the galvanometer has changed from zero indicates the extent to which the gas has absorbed the radiant heat from the righthand heat source and blocked this heat from radiating to the thermopile through the tube If a highly polished metal disc is placed in the space between the thermopile and the brass tube it will completely block the radiant heat coming out of the tube from reaching the thermopile thereby deflecting the galvanometer by the maximum extent possible with respect to blockage in the tube Thus the system has minimum and maximum readings available and can express other readings in percentage terms The galvanometer s responsiveness was physically nonlinear but well understood and mathematically linearizable In one of his public lectures to non professional audiences Tyndall gave the following indication of instrument sensitivity My assistant stands several feet off I turn the thermopile towards him The heat from his face even at this distance produces a deflection of 90 degrees on the galvanometer dial I turn the instrument towards a distant wall judged to be a little below the average temperature of the room The needle descends and passes to the other side of zero declaring by this negative deflection that the pile feels the chill of the wall quote from Six Lectures On Light To reduce interference from human bodies the galvanometer was read through a telescope from across the room The thermopile amp galvanometer system was invented by Leopoldo Nobili and Macedonio Melloni Melloni measured radiant heat absorption in solids and liquids but didn t have the sensitivity for gases Tyndall greatly improved the sensitivity of the overall setup including putting an offsetting heat source on the other side of the thermopile and putting the gas in a brass tube and as a result of his superior apparatus he was able to confidently reach conclusions that were quite different from Melloni s concerning radiant heat in gases book ref below in chapter I Air from which water vapor and carbon dioxide had been removed deflected the galvanometer dial by less than 1 degree in other words a detectable but very small amount same ref chapter II Many other gases and vapors deflected the galvanometer by a large amount thousands of times greater than air As a check on his system s reliability Tyndall painted the inside walls of the brass tube with a strong absorber of radiant heat namely lampblack This greatly reduced the radiant heat that reached the thermopile when the tube was empty Nevertheless the percentage absorptions by the different gases and vapors relative to the empty tube were largely and essentially unchanged by this change to the absorption property of the tube s walls That s excluding a few gases and vapors such as chlorine that must be excluded because they tarnish brass changing its heat reflectivity As another test of the reliability of the system the long brass tube was cut to about a quarter of its original length and the exact same quantity of gas was released into the shorter tube Thus the shorter tube will have about four times higher gas density It was found that the percentage of radiant heat absorbed by or transmitted through the gas relative to the empty tube state was entirely unchanged by this even though the two tubes don t have equal empty tube states Varying the absolute quantity of the gas in the tube causes corresponding changes in the absorption percentages but varying the density doesn t matter nor does the absolute value of the empty tube reference point The emission spectrum of the particular source of heat makes a difference sometimes a big difference in the amount of radiant heat a gas will absorb and different gases can respond differently to a change in the source Tyndall said in 1864 a long series of experiments enables me to state that probably no two substances at a temperature of 100 C emit heat of the same quality i e of the same spectral profile The heat emitted by isinglass for example is different from that emitted by lampblack and the heat emitted by cloth or paper differs from both Looking at an electrically heated platinum wire it is obvious to the human eye that the heat s spectral profile depends on whether the wire is heated to dull red bright orange or white hot Some gases were relatively stronger absorbers of the dull red platinum heat while other gases were relatively stronger absorbers of the white hot platinum heat he found For his original and primary benchmark in 1859 he used the heat from 100 C lampblack akin to a theoretical blackbody radiator Later he got some of his more interesting findings from using other heat sources E g when the source of radiant heat was any one kind of gas then this heat was strongly absorbed by another body of the same kind of gas regardless of whether the gas was a weak absorber of broad spectrum sources In the illustration above the radiant heat that is going into the brass tube comes from a pot of simmering water the heat radiates from the exterior surface of the pot not from the water and not from the gas flame that keeps the water at a simmer An alternative illustration with a modified setup taken from the same book page 112 is shown below The main difference is that the heat source is separated from the brass tube by open air which eliminates the need for circulating cold water cooling at the interface between heat source and brass tube Tarix 10 yanvar 1861 Menbe I The Bakerian Lecture On the absorption and radiation of heat by gases and vapours and on the physical connexion of radiation absorption and conduction It has been subsequently annotated Muellif John Tyndall Diger versiyalar Installation de Tyndalls pour la mesure de l absorption de chaleur radiante par des gaz annote svg French language Lisenziya Public domain Public domain false false This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author s life plus 70 years or fewer This work is in the public domain in the United States because it was published or registered with the U S Copyright Office before January 1 1930 Bu fayl butun elaqeli ve qonsu huquqlar da daxil olmaqla muellif huquqlari qanununa esasen melum mehdudiyyetlerden azad oldugu mueyyen edilmisdir https creativecommons org publicdomain mark 1 0 PDM Creative Commons Public Domain Mark 1 0 false falseBasliqlarazerbaycancaBu faylin neyi temsil etdiyine dair bir setirlik izahat elave etingilisTyndalls setup for measuring radiant heat absorption by gasesBu faylda tesvir olunan elementlertesvir edirmedia type nbsp ingilisimage svg xml Faylin tarixcesi Faylin evvelki versiyasini gormek ucun gun tarix bolmesindeki tarixlere klikleyin Tarix VaxtMiniaturOlculerIstifadeciSerh hal hazirki18 30 23 avqust 2020960 893 329 KB EfbrazilUploaded a work by John Tyndall from The illustration appears in John Tyndall 039 s 1872 book 039 039 Contributions to Molecular Physics in the Domain of Radiant Heat 039 039 https archive org search php query contributions 20to 20molecular 20physics 20in 20the 20domain 20of 20radiant 20heat downloadable at Archive org It has been subsequently annotated in colored typeface The book is a compilation of research reports published by Tyndall in the 1860s The particular illustration is part of a repor Faylin istifadesi Asagidaki sehife bu fayli istifade edir Iqlim deyisikliyi Faylin qlobal istifadesi Bu fayl asagidaki vikilerde istifade olunur bn wikipedia org layihesinde istifadesi জলব য পর বর তন cs wikipedia org layihesinde istifadesi Historie vedy o zmene klimatu en wikipedia org layihesinde istifadesi John Tyndall Climate change History of climate change science Portal Climate change Selected article Portal Climate change Selected article 23 Portal Climate change fa wikipedia org layihesinde istifadesi پیش نویس تغییر اقلیم he wikipedia org layihesinde istifadesi היסטוריה של מדע שינויי האקלים hy wikipedia org layihesinde istifadesi Ջոն Թինդալ pl wikipedia org layihesinde istifadesi Dwutlenek wegla w atmosferze mlodej Ziemi pt wikipedia org layihesinde istifadesi Usuario CaveatLector2022 Historia da ciencia das alteracoes climaticas Historia da ciencia das alteracoes climaticas uz wikipedia org layihesinde istifadesi Foydalanuvchi Anjaniy qumloq zh wikipedia org layihesinde istifadesi 氣候變化科學史Metamelumatlar Bu faylda fotoaparat ve ya skanerle elave olunmus melumatlar var Eger fayl sonradan redakte olunubsa bezi parametrler bu sekilde gosterilenlerden ferqli ola biler Genislik960Hundurluk893 Menbe https az wikipedia org wiki Fayl Tyndalls setup for measuring radiant heat absorption by gases annotated svg