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| | Ask for educational titles. Yet generally plainly showcased on the market of primary blockbusters at game stores or electronic portions, however are in the market. Speak to other moms and men or question employees for specific suggestions, as details really exist that help by helping cover their learning languages, learning concepts and practicing mathematics.<br><br>Seeking are a parent or gaurdian of any hardly any one who appreciates stealing part in video games, be familiar with multi-player and [https://Www.Gov.uk/search?q=on-line+video on-line video] game titles options. These features give your kid in order to really interact with many extra gamers throughout the . As good as the situation is for your child in order to talk about with others, you manage not know who any of us on the other finalize is.<br><br>Internet marketing business inside your games when you find yourself been doing playing them. Should you adored this information in addition to you wish to acquire more information relating to [http://circuspartypanama.com clash of clans cheats deutsch] generously go to our web page. Quite retailers provide discount rates or credit score on to your next buy each and every time you business your clash of clans sur pc tlcharger living in. You can hit upon the next online video game you would like due to the affordable price as soon you try this. All things considered, clients don't need the dvd games as soon as you defeat them.<br><br>Read the evaluations and see currently the trailers before buying a relevant video game. Ensure it is one thing you have decided you're before you get in which. These video games aren't low-cost, and also you will get nearly as a long way cash whenever you companies inside a employed game which you have simply just utilized several times.<br><br>Sports season is here and therefore going strong, and including many fans we far for Sunday afternoon when the games begin. If you have played and liked Soul Caliber, you will love this excellent game. The succeeding best is the Food Cell which will at random , fill in some pieces. Defeating players that by any means that necessary can be some reason that pushes all involved to use Words due to Friends Cheat. One particular app requires you to answer 40 questions by having varying degrees of difficulties.<br><br>Had you been aware that some mobile computer games are educational machines? If you know a children that likes to participate in video games, educational opportunities are a fantastic refers to to combine learning containing entertaining. The Internet can connect you with thousands of parents with similar values and are unquestionably more than willing that will share their reviews as well as notions with you.<br><br>If you want to master game play regarding shooter video games, pro your weapons. See everything there is learn about each and all weapon style in sport. Each weapon excels in the certain ways, but falls short in others. When you know the exact pluses and minuses of each weapon, you can use them to full advantage. |
| {{Use dmy dates|date=August 2013}}
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| {{Infobox scientist
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| | name = Sir Edward Appleton
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| | image = Appleton.jpg
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| | image_size = 190px
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| | caption =
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| | birth_name = Edward Victor Appleton
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| | birth_date = {{Birth date|1892|9|6|df=y}}
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| | birth_place = [[Bradford]], [[West Yorkshire]], [[England]]
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| | death_date = {{Death date and age|1965|4|21|1892|9|6|df=y}}
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| | death_place = [[Edinburgh]], [[Scotland]]
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| | nationality = [[England|English]]
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| | field = [[Physics]]
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| | workplaces = [[University of Cambridge]]<br />[[King's College London]]<br />[[University of Edinburgh]]<br>[[Cavendish Laboratory]]
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| | alma_mater = [[St John's College, Cambridge]]
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| | doctoral_advisor = <!--The PhD had only just started in Cambridge in 1919-->
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| | academic_advisors = [[J. J. Thomson]] <br />[[Ernest Rutherford]]
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| | doctoral_students =
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| | notable_students = [[J. A. Ratcliffe]]<br />[[Charles Oatley]]
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| | known_for = [[Ionosphere|Ionospheric Physics]]<ref>{{cite doi|10.1038/157691a0}}</ref><ref>{{cite doi|10.1038/115333a0}}</ref><ref>{{cite doi|10.1126/science.106.2740.17}}</ref><ref>{{cite doi|10.1038/136548b0}}</ref><ref name="ion">{{Cite journal|author=Appleton, EV|year=1932|title=Wireless Studies of the Ionosphere|journal=J. Inst. Elec. Engrs.|doi=10.1049/jiee-1.1932.0144}}</ref><ref>{{Cite doi|10.1098/rspa.1927.0093}}</ref><ref>{{Cite doi|10.1098/rspa.1925.0149}}</ref><br />[[F region|Appleton layer]]<Br>Demonstrating existence of [[Kennelly–Heaviside layer]]
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| | prizes = {{nowrap|[[Nobel Prize in Physics]] (1947)}}<br>[[Fellow of the Royal Society]] (1927)<ref name="frs">{{cite doi|10.1098/rsbm.1966.0001}}</ref><br>[[Faraday Medal]]<br>[[Hughes Medal]]<br>[[Royal Medal]]<br>[[Appleton Medal and Prize|Chree Medal]]
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| }}
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| '''Sir Edward Victor Appleton''', [[Order of the British Empire|GBE]], [[Knight Commander of the Order of the Bath|KCB]], [[Fellow of the Royal Society|FRS]]<ref name="frs"/> (6 September 1892 – 21 April 1965) was an [[United Kingdom|English]] [[physicist]].<ref>{{cite web|title=Sir Edward Appleton (1892–1965)|url=http://www.bbc.co.uk/history/historic_figures/appleton_edward.shtml}}</ref><ref>{{cite doi|10.1063/1.3047706}}</ref><ref>{{cite encyclopedia | last=Süsskind | first=Charles | title=Appleton, Edward Victor | encyclopedia=[[Dictionary of Scientific Biography]] | volume=1 | pages=195–196 | publisher=Charles Scribner's Sons | location=New York | year=1970 | isbn=0-684-10114-9}}</ref><ref>{{Cite doi|10.1098/rsta.1975.0088}}</ref><ref name="odnb">{{cite doi|10.1093/ref:odnb/30426 }}</ref><ref>{{cite doi|10.1126/science.119.3082.103}}</ref><ref name="pergamon">{{Cite book|last=Clark|first=Ronald|year=1971|title=Sir Edward Appleton|publisher=Pergamon Press |location=Oxford}}</ref>
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| ==Biography==
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| Appleton was born in [[Bradford]], [[West Yorkshire]], and educated at [[Hanson School|Hanson Grammar School]]. At the age of 18 he won a scholarship to [[St John's College, Cambridge]]. He graduated with a first class degree in Natural Sciences.
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| During the First World War he joined the [[Duke of Wellington's Regiment|West Riding Regiment]], and later transferred to the [[Royal Engineers]]. After returning from active service in [[World War I]], Appleton became assistant demonstrator in experimental physics at the [[Cavendish Laboratory]] in 1920. He was professor of physics at [[King's College London]] (1924–36) and professor of natural philosophy at the [[University of Cambridge]] (1936–39). From 1939 to 1949 he was secretary of the [[Department of Scientific and Industrial Research]]. Knighted in 1941, he received the 1947 [[Nobel Prize in Physics]] for his contributions to the knowledge of the [[ionosphere]],<ref name="ion"/> which led to the development of [[radar]].
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| From 1949 until his death in 1965, he was Principal and Vice-Chancellor of the [[University of Edinburgh]].<ref>{{cite book | first=Derek A J| last=Lister | title=Bradford's Own | year=2004 | publisher=Sutton | isbn=0-7509-3826-9}}</ref> In 1956, the BBC invited him to deliver the annual [[Reith Lectures]]. Across a series of six radio broadcasts, titled ''Science and the Nation'', Appleton explored the many facets of scientific activity in Britain at the time.
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| == Works ==
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| Appleton had observed that the strength of the radio signal from a transmitter on a frequency such as the medium wave band and over a path of a hundred miles or so was constant during the day but that it varied during the night. This led him to believe that it was possible that two radio signals were being received. One was travelling along the ground, and another was reflected by a layer in the upper atmosphere. The fading or variation in strength of the overall radio signal received resulted from the [[Interference (wave propagation)|interference]] pattern of the two signals.
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| The existence of a reflecting atmospheric layer was not in itself a completely new idea. Balfour Stewart had suggested the idea in the late nineteenth century to explain rhythmic changes in the earth’s magnetic field. More recently, in 1902, [[Oliver Heaviside]] and A. E. Kennelly had suggested such a hypothesis may explain the success Marconi had in transmitting his signals across the Atlantic. Calculations had shown that natural bending of the radio waves was not sufficient to stop them from simply “shooting off” into empty space before they reached the receiver.
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| Appleton thought the best place to look for evidence of the ionosphere was in the variations he believed it was causing around sunset in radio signal receptions. It was sensible to suggest these variations were due to the interference of two waves but an extra step to show that the second wave causing the interference (the first being the ground wave) was coming down from the ionosphere. The experiment he designed had two methods to show ionospheric influence and both allowed the height of the lower boundary of reflection (thus the lower boundary of the reflecting layer) to be determined. The first method was called frequency modulation and the second was to calculate the angle of arrival of the reflected signal at the receiving aerial.
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| The frequency modulation method exploits the fact that there is a path difference between the ground wave and the reflected wave, meaning they travel different distances from sender to receiver.
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| Let the distance AC travelled by the ground wave be h and the distance ABC travelled by the reflected wave h’. The path difference is:
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| <math> h'-h=D </math>
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| The wavelength of the transmitted signal is λ . The number of wavelengths difference between the paths h and h’ is:
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| <math> \frac{h-h'}{\lambda}=\frac{D}{\lambda}=N </math> | |
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| If N is an integer number, then constructive interference will occur, this means a maximum signal will be achieved at the receiving end. If N is an odd integer number of half wavelengths, then destructive interference will occur and a minimum signal will be received. Let us assume we are receiving a maximum signal for a given wavelength λ. If we start to change λ, this is the process called frequency modulation, N will no longer be a whole number and destructive interference will start to occur, meaning the signal will start to fade. Now we keep changing λ until a maximum signal is once again received. The means that for our new value λ’, our new value N’ is an also an integer number. If we have lengthened λ then we know that N’ is one less than N. Thus:
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| <math> N-N'=\frac{D}{\lambda}-\frac{D}{\lambda'}=1 </math>
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| Rearranging for D gives:
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| <math> D=h-h'=\frac{1}{\frac{1}{\lambda}-\frac{1}{\lambda'}} </math>
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| As we know λ and λ’, we can calculate D. Using the approximation that ABC is an isosceles triangle, we can use our value of D to calculate the height of the reflecting layer. This method is a slightly simplified version of the method used by Appleton and his colleagues to work out a first value for the height of the ionosphere in 1924. In their experiment, they used the [[BBC]] broadcasting station in [[Bournemouth]] to vary the wavelengths of its emissions after the evening programmes had finished. They installed a receiving station in Oxford to monitor the interference effects. The receiving station had to be in [[Oxford]] as there was no suitable emitter at the right distance of about 100 km from Cambridge in those days.
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| This frequency modulation method revealed that the point from which waves were being reflected was approximately 90 km. However, it did not establish that the waves were reflected from above, indeed they may have been coming from hills somewhere between Oxford and Bournemouth. The second method, which involved finding the angle of incidence of the reflected waves at the receiver, showed for sure that they were coming from above. Triangulations from this angle gave results for the height of reflection compatible with the frequency modulation method. We will not go into this method in detail because it involves fairly complex calculations using Maxwell’s electromagnetic theory.
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| Far from being conclusive, the success of the Oxford-Bournemouth experiment revealed a vast new field of study to be explored. It showed that there was indeed a reflecting layer high above the earth but it also posed many new questions. What was the constitution of this layer, how did it reflect the waves, was it the same all over the earth, why did its effects change so dramatically between day and night, did it change throughout the year? Appleton would spend the rest of his life answering these questions. He developed a magneto-ionic theory based on the previous work of [[Hendrik Lorentz|Lorentz]] and [[James Clerk Maxwell|Maxwell]] to model the workings of this part of the atmosphere. Using this theory and further experiments, he showed that the so-called [[Kennelly-Heaviside layer]] was heavily ionised and thus conducting. This led to the term ionosphere. He showed free electrons to be the ionising agents. He discovered that the layer could be penetrated by waves above a certain frequency and that this critical frequency could be used to calculate the electron density in the layer. However these penetrating waves would also be reflected back, but from a much higher layer. This showed the ionosphere had a much more complex structure than first anticipated. The lower level was labelled E – Layer, reflected longer wavelengths and was found to be at approximately 125 km. The high level, which had much higher electron density, was labelled F – Layer and could reflect much shorter wavelengths that penetrated the lower layer. It is situated 300 – 400 km above the earth’s surface. It is this which is often referred to as the Appleton Layer as is responsible for enabling most long range short wave telecommunication.<ref>{{cite web |url=http://www.ieeeghn.org/wiki/index.php/Edward_V._Appleton |title=Edward V. Appleton |author=IEEE Global History Network |year=2011 |publisher=IEEE History Center |accessdate=14 July 2011}}</ref>
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| The magneto-ionic theory also allowed Appleton to explain the origin of the mysterious fadings heard on the radio around sunset. During the day, the light from the sun causes the molecules in the air to become ionised even at fairly low altitudes. At these low altitudes, the density of the air is great and thus the electron density of ionised air is very large. Due to this heavy ionisation, there is strong absorption of electromagnetic waves caused by ‘electron friction’. Thus in transmissions over any distance, there will be no reflections as any waves apart from the one at ground level will be absorbed rather than reflected. However, when the sun sets, the molecules slowly start to recombine with their electrons and the free electron density levels drop. This means absorption rates diminish and waves can be reflected with sufficient strengths to be noticed, leading to the interference phenomena we have mentioned. For these interference patterns to occur though, there must not simply be the presence of a reflected wave but a change in the reflected wave. Otherwise the interference is constant and fadings would not be heard. The received signal would simply be louder or softer than during the day. This suggests the height at which reflection happens must slowly change as the sun sets. Appleton found in fact that it increased as the sun set and then decreased as the sun rose until the reflected wave was too weak to record. This variation is compatible with the theory that ionisation is due to the sun’s influence. At sunset, the intensity of the sun’s radiation will be much less at the surface of the earth than it is high up in the atmosphere. This means ionic recombination will progress slowly from lower altitudes to higher ones and therefore the height at which waves are reflected slowly increases as the sun sets.
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| The basic idea behind Appleton’s work is so simple that it is hard to understand at first how he devoted almost all of his scientific career to its study. However, in the last couple of paragraphs some of the complexities of the subject have been introduced. Like many other fields, it is one that grows in intricacy the more it is studied. By the end of his life, ionospheric observatories had been set up all over the world to provide a global map of the reflecting layers. Links were found to the 11 year sunspot cycle and the [[Aurora Borealis]], the magnetic storms that occur in high latitudes. This became particularly relevant during the second world war when the storms would lead to radio blackouts. Thanks to Appleton’s research, the periods when these would occur could be predicted and communication could be switched to wavelengths that would be least affected. [[RADAR]], another crucial wartime innovation, was one that came about thanks to Appleton’s work. On a very general level, his research consisted in determining the distance of reflecting objects from radio signal transmitters. This is exactly the idea of RADAR and the flashing dots that appear on the screen (a cathode ray tube) scanned by the circulating ‘searcher’ bar. This system was developed partly by Appleton as a new method, called the pulse method, to make ionospheric measurements. It was later adapted by [[Robert Watson-Watt]] to detect aeroplanes. Nowadays, ionospheric data is important when communications with satellites are considered. The correct frequencies for these signals must be selected so that they actually reach the satellites without being reflected or deviated before.
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| In 1974 the [[Radio Research Station|Radio and Space Research Station]] was renamed the [[Appleton Laboratory]] in honour of the man who had done so much to establish the UK as a leading force in ionospheric research, and had been involved with the station first as a researcher and then as secretary of its parent body, the Department of Scientific and Industrial Research.
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| == Honours and awards ==
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| Appleton was awarded the following:
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| * Fellow of the [[Royal Society]] (1927)<ref name="frs"/>
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| * Foreign Honorary Member of the [[American Academy of Arts and Sciences]] (1936)<ref name=AAAS>{{cite web|title=Book of Members, 1780–2010: Chapter A|url=http://www.amacad.org/publications/BookofMembers/ChapterA.pdf|publisher=American Academy of Arts and Sciences|accessdate=19 April 2011}}</ref>
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| * [[Nobel Prize in Physics]] (1947)
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| * [[Faraday Medal]]
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| * [[Hughes Medal]]
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| * [[Royal Medal]]
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| * [[Appleton Medal and Prize|Chree Medal]]
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| In addition the following are named in his honour:
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| * the [[Rutherford Appleton Laboratory]]
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| * the [[Appleton Medal and Prize]]
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| * the Appleton Suite at Bradford Registry Offices
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| * the [[Appleton Tower]] at the [[University of Edinburgh]]
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| * the [http://www.bilk.ac.uk/college/depts/science/ Appleton Science Building] at [[Bradford College (England)|Bradford College]]
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| * Appleton Academy, a new school, which will replace Wyke Manor School and High Fernley Primary School in the Wyke district of [[Bradford|South Bradford]]. This will be the first 'through-school' in West Yorkshire.
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| * The crater [[Appleton (crater)|Appleton]] on the [[Moon]] is named in his honour.
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| * The Appleton Layer, which is the higher atmospheric ionized layer above the E-layer
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| * The annual [http://www.theiet.org/events/appleton/ Appleton Lecture] at the [[Institution of Engineering and Technology]]
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| * Likely inspiration for the pseudonym [[Victor Appleton]] – the fictitious author of the [[Tom Swift]] series of novels{{or|date=September 2013}}
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| == References ==
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| {{Reflist}}
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| ==Further reading==
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| * {{Cite book|last=Appleton |first=EV |author2=Ratcliffe, JA|year=1929|title=The Physical Principles of Wireless|publisher=Methuen }}
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| * [http://conferences.theiet.org/lectures/appleton/index.htm IET Appleton lectures]
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| * [http://nobelprize.org/physics/laureates/1947/index.html "Sir Edward Victor Appleton"]. ''nobelprize.org''. Accessed 21 October 2007. (Citation: Nobel Prize in Physics: 1947, "for his investigations of the physics of the upper atmosphere especially for the discovery of the so-called Appleton layer." [Hyperlinked account. Provides link to BBC ''Historic Figures'' biography.]
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| * [http://nobelprize.org/nobel_prizes/physics/laureates/1947/appleton-bio.html "Sir Edward Victor Appleton: Nobel Prize in Physics 1947"] – Biography from ''Nobel Lectures, Physics 1942–1962'' (Amsterdam: Elsevier Publishing Company, 1964). [Hyperlinked in previous entry.]
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| * [http://www.bbc.co.uk/history/historic_figures/appleton_edward.shtml "Sir Edward Victor Appleton (1892–1965):] Appleton was an English physicist and Nobel prize winner who discovered the ionosphere." ''Historic Figures'', ''bbc.co.uk''. Accessed 21 October 2007. (Photograph of Appleton c. 1935 ©). [Provides link to Nobel Foundation account, listed above.]
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| * [http://nobelprize.org/nobel_prizes/physics/laureates/1947/appleton-bio.html Nobelprize.org Biography]
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| * ''[http://www.bbc.co.uk/programmes/p00h9lkv Science and the Nation]'' The BBC [http://www.bbc.co.uk/reithlectures Reith Lectures], 1956, by Edward Appleton
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| * {{cite web|last=Davis|first=Chris|title=Treasure in the Basement|url=http://www.backstagescience.com/videos/basement_treasures.html|work=Backstage Science|publisher=[[Brady Haran]]}}
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| {{s-start}}
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| {{s-aca}}
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| {{succession box | before=[[John Fraser (educator)|Sir John Fraser]]|title=[[Edinburgh University Principals|Principals of Edinburgh University]] | years=1948–1965| after=[[Michael Swann]]}}
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| {{s-end}}
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| {{Nobel Prize in Physics Laureates 1926–1950}}
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| {{IEEE Medal of Honor Laureates 1951–1975}}
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| {{Authority control|VIAF=54941774}}
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| {{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
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| | NAME = Appleton, Edward Victor
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| | ALTERNATIVE NAMES =
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| | SHORT DESCRIPTION =English physicist
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| | DATE OF BIRTH = 6 September 1892
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| | PLACE OF BIRTH = [[Bradford]], [[West Yorkshire]], [[England]]
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| | DATE OF DEATH = 21 April 1965
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| | PLACE OF DEATH = [[Edinburgh]], [[Scotland]]
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| }}
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| {{DEFAULTSORT:Appleton, Edward Victor}}
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| [[Category:1892 births]]
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| [[Category:1965 deaths]]
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| [[Category:Academics of King's College London]]
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| [[Category:Fellows of King's College London]]
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| [[Category:Academics of the University of London]]
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| [[Category:Alumni of St John's College, Cambridge]]
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| [[Category:Alumni of the University of Edinburgh]]
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| [[Category:English academics]]
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| [[Category:English physicists]]
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| [[Category:Fellows of the Royal Society]]
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| [[Category:IEEE Medal of Honor recipients]]
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| [[Category:Knights Grand Cross of the Order of the British Empire]]
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| [[Category:Nobel laureates in Physics]]
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| [[Category:People from Bradford]]
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| [[Category:Principals of the University of Edinburgh]]
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| [[Category:Royal Medal winners]]
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| [[Category:Knights Commander of the Order of the Bath]]
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| [[Category:Recipients of King Haakon VII's Cross of Liberty]]
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| [[Category:Honorary Fellows of the Royal Society of Edinburgh]]
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| [[Category:Fellows of the American Academy of Arts and Sciences]]
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| [[Category:English Nobel laureates]]
| |
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