Chapter 1 Neither Indeed Would I Have Put My Selfe to the Labour Of

Total Page:16

File Type:pdf, Size:1020Kb

Chapter 1 Neither Indeed Would I Have Put My Selfe to the Labour Of Notes Neither indeed would I have put my selfe to the labour of writing any Notes at all, if the booke could as well have wanted them, as I could easilie have found as well, or better to my minde, how to bestow my time. Marcus Aurelius Antoninus. Chapter 1 1. W.S. Gilbert, The Mikado, 1885. 2. Commentators are divided on whether Hazlitt should be regarded as an essayist or a critic; thus Priestley [1960, p. 6] prefers to de­ scribe him as an essayist, while Brett [1977, p. 5] regards him as a biographical critic. 3. The first abstract presentation of this idea may be found in Plato's Republic, the parable reading as follows in the Analysis to Book VII, Steph. 514-517 of Jowett's translation: Imagine human beings living in an underground den which is open towards the light; they have been there from child­ hood, having their necks and legs chained, and can only see into the den. At a distance there is a fire, and between the fire and the prisoners a raised way, and a low wall is built along the way, like the screen over which marionette players show their puppets. Behind the wall appear mov­ ing figures, who hold in their hands various works of art, and among them images of men and animals, wood and stone, and some of the passers-by are talking and others silent ... , they see only the shadows of the images which the fire throws on the wall of the den; to these they give names, and if we add an echo which returns from the wall, the voices of the passengers will seem to proceed from the shadows. Suppose now that you suddenly turn them round and make them look with pain and grief to themselves at 522 Notes: chapter 1 the real images; will they believe them to be real? Will not their eyes be dazzled, and will they not try to get away from the light to something which they are able to behold with­ out blinking? And suppose further, that they are dragged up a steep and rugged ascent into the presence of the sun himself, will not their sight be darkened with the excess of light? Some time will pass before they get the habit of perceiving at all; and at first they will be able to perceive only shadows and reflections in the water; then they will recognize the moon and the stars, and will at length be­ hold the sun in his own proper place as he is .... How will they rejoice in passing from darkness to light! How worth­ less to them will seem the honours and glories of the den! But now imagine further, that they descend into their old habitations;- in that underground dwelling they will not see as well as their fellows, and will not be able to compete with them in the measurement of the shadows on the wall ... Now the cave or den is the world of sight, the fire is the sun, the way upwards is the way to knowledge, and in the world of knowledge the idea of good is last seen and with difficulty, but when seen is inferred to be the author of good and right. [1888, pp. xcviii-xcix] The allegory was rehearsed by Bacon in his Novum Organum of 1620, where we read The Idols [i.e. illusions or false appearances] of the Cave are the Idols of the individual man. For everyone (besides the errors common to human nature in general) has a cave or den of his own, which refracts and discolours the light of nature; owing either to his own proper and peculiar na­ ture; or to his education and conversation with others; or to the reading of books, and the authority of those whom he esteems and admires; or to the differences of impressions, accordingly as they take place in a mind preoccupied and predisposed or in a mind indifferent and settled; or the like. So that the spirit of man (according as it is meted out to different individuals) is in fact a thing variable and full of perturbation, and governed as it were by chance. [Aphorism XLII] This translation of Bacon's original Latin text is by Robert Leslie El­ lis, some of whose statistical work will be discussed in a later chapter. 4. See Romanov [1974], Sabatier [1978] and Talenti [1986]. 5. For a good discussion of moment problems see Shohat & Tamarkin [1943]. Notes: chapter 1 523 6. For further discussion of the role of inverse probability in error mea­ surement see Edgeworth [1911]. 7. For instance Salmon [1966, p. 118] finds that plausibility arguments not only are an essential ingredient in scientific inference, but also "embody considerations relevant to the evaluation of prior probabili­ ties" (Salmon's views on this matter have been discussed, somewhat slightingly, by Weimer [1975]). For a discussion of mathematical mod­ els of uncertainty and indeterminacy see Walley [1991, §1.8]. 8. See also §5.14. 9. The original reads as follows: At hic tandem nobis aqua hrerere videtur, cum vix in pau­ cissimis prrestare hoc liceat, nec alibi fere succedat. quam in alere ludis, quos primi inventores ad requitatem ipsis conciliandam data opera sic instituerunt, ut certi notique essent numeri casuum, ad quos sequi debet lucrum aut damnum, & ut casus hi omnes pari facilitate obtingere possent. In creteris enim plerisque vel a naturre operatione vel ab hominum arbitrio pendentibus effectis id neutiquam locum habet. [po 223] 10. Bernoulli's words are Verum enimvero alia hie nobis via suppetit, qua quresitum obtineamus; & quod a priori elicere non datur, saltern apos­ teriori, hoc est, ex eventu in similibus exemplis multoties observato eruere licebit; quandoquidem prresumi debet, tot casibus unumquodque posthac contingere & non contingere posse, quoties id antehac in simili rerum statu contigisse & non contigisse fuerit deprehensum. [po 224] 11. The original runs as follows: Hoc igitur est illud Problema, quod evulgandum hoc loco proposui, post quam jam per vicennium pressi, & cujus tum novitas, tum summa utilitas cum pari conjuncta difficul­ tate omnibus reliquis hujus doctrinre capitibus pondus & pretium superaddere potest. [po 227] Both David [1962, p. 136] and Sung [1966, p. 42] translate "super­ addere" as "exceed", the impression thus being conveyed that the novelty, f3c. of the problem exceed the value of the rest of the work. The translation I have given here, which I believe to be more ap­ propriate, agrees with that given by de Moivre [1756, p. 254] and Haussner [1899, II, p. 92]. 524 Notes: chapter 1 12. This passage runs as follows in the original: Sit igitur numerus casuum fertilium ad numerum steril­ ium vel prrecise vel proxime in ratione r / s, adeoque ad numerum omnium in ratione r/(r + s) seu r/t, quam ra­ tionem terminent limites (r+1)/t & (r-1)/t. Ostendendum est, tot posse capi experimenta, ut datis quotlibet (puta c) vicibus verisimilius evadat, numerum fertilium observa­ tionum intra hos limites quam extra casurum esse, h. e. numerum fertilium ad numerum omnium observationum rationem habiturum nec majorem quam (r + l)/t, nec mi­ norem quam (r - l)/t. [po 236] 13. Compare Sung [1966, p. 4]. 14. See also David [1962, p. 137]. 15. The passage translated here is Unde tandem hoc singulare sequi videtur, quod si eventuum omnium observationes per totam reternitatem continuaren­ tur, (probabilitate ultimo in perfectam certitudinem abe­ unte) omnia in mundo certis rationibus & constanti vicis­ situdinis lege contingere deprehenderentur; adeo ut etiam in maxime casu ali bus atque fortuitis quandam quasi neces­ sitatem, &, ut sic dicam, fatalitatem agnoscere teneamur. [p.239] 16. See Hacking [1975, pp. 149,154]. 17. The presence of this passage was drawn to the attention of the sta­ tistical community by S.M. Stigler in 1983. 18. The presence of the expectation operator here rather than the prob­ abilistic one is of no moment. 19. The distinction was, it would appear, also noted by Good [1959], who wrote of Bayes's attempt at an inversion of Bernoulli's Theorem. Stigler [1986a, p. 100] regards the inversion of the results of Bernoulli and de Moivre as "The chief conceptual step taken in the eighteenth century toward the application of probability to quantitative infer­ ence" . 20. The sketch illustrating the situation detailed in the following quota­ tion may be found in Chapter 4, Figure 4.1. 21. Each of these symptoms may be viewed as a complex of symptoms. 22. In translation: "0 happy he who can determine the causes of events!" Commentators agree in stating that Virgil is following Lucretius here. A similar sentiment was expressed in Matthew Arnold's Memorial Verses of 1850: "And he [i.e. Goethe] was happy, if to know, causes of things ... " . 23. The connexion is also considered in Keynes [1921, pp. 401-402,420- 422]. Notes: chapter 2 525 24. The idea of Pr[Plq], the probability of p on data q, is taken as funda­ mental by Jeffreys [1961, p. 15]. 25. Perks's paper of 1947 is an important one in the annals of inverse probability: not only are exceedingly pertinent comments made on this topic, but a new indifference rule is proposed. 26. See Robert [1994, p. 370]. 27. See O'Hagan [1994, p. 134]. 28. Seidenfeld [1979, p. 19]. 29. The name of this "eminent professor" is not given, although a footnote to this page gives the other lecturers as Dr Venn, Professor Weldon and Sir Robert Ball. Chapter 2 1. This description is from Hacking's introduction to the English trans­ lation of Maistrov [1974, p.
Recommended publications
  • Mathematics Is a Gentleman's Art: Analysis and Synthesis in American College Geometry Teaching, 1790-1840 Amy K
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2000 Mathematics is a gentleman's art: Analysis and synthesis in American college geometry teaching, 1790-1840 Amy K. Ackerberg-Hastings Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Higher Education and Teaching Commons, History of Science, Technology, and Medicine Commons, and the Science and Mathematics Education Commons Recommended Citation Ackerberg-Hastings, Amy K., "Mathematics is a gentleman's art: Analysis and synthesis in American college geometry teaching, 1790-1840 " (2000). Retrospective Theses and Dissertations. 12669. https://lib.dr.iastate.edu/rtd/12669 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margwis, and improper alignment can adversely affect reproduction. in the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted.
    [Show full text]
  • Cavendish Weighs the Earth, 1797
    CAVENDISH WEIGHS THE EARTH Newton's law of gravitation tells us that any two bodies attract each other{not just the Earth and an apple, or the Earth and the Moon, but also two apples! We don't feel the attraction between two apples if we hold one in each hand, as we do the attraction of two magnets, but according to Newton's law, the two apples should attract each other. If that is really true, it might perhaps be possible to directly observe the force of attraction between two objects in a laboratory. The \great moment" when that was done came on August 5, 1797, in a garden shed in suburban London. The experimenter was Lord Henry Cavendish. Cavendish had inherited a fortune, and was therefore free to follow his inclinations, which turned out to be scientific. In addition to the famous experiment described here, he was also the discoverer of “inflammable air", now known as hydrogen. In those days, science in England was often pursued by private citizens of means, who communicated through the Royal Society. Although Cavendish studied at Cambridge for three years, the universities were not yet centers of scientific research. Let us turn now to a calculation. How much should the force of gravity between two apples actually amount to? Since the attraction between two objects is proportional to the product of their masses, the attraction between the apples should be the weight of an apple times the ratio of the mass of an apple to the mass of the Earth. The weight of an apple is, according to Newton, the force of attraction between the apple and the Earth: GMm W = R2 where G is the \gravitational constant", M the mass of the Earth, m the mass of an apple, and R the radius of the Earth.
    [Show full text]
  • Downloading Material Is Agreeing to Abide by the Terms of the Repository Licence
    Cronfa - Swansea University Open Access Repository _____________________________________________________________ This is an author produced version of a paper published in: Transactions of the Honourable Society of Cymmrodorion Cronfa URL for this paper: http://cronfa.swan.ac.uk/Record/cronfa40899 _____________________________________________________________ Paper: Tucker, J. Richard Price and the History of Science. Transactions of the Honourable Society of Cymmrodorion, 23, 69- 86. _____________________________________________________________ This item is brought to you by Swansea University. Any person downloading material is agreeing to abide by the terms of the repository licence. Copies of full text items may be used or reproduced in any format or medium, without prior permission for personal research or study, educational or non-commercial purposes only. The copyright for any work remains with the original author unless otherwise specified. The full-text must not be sold in any format or medium without the formal permission of the copyright holder. Permission for multiple reproductions should be obtained from the original author. Authors are personally responsible for adhering to copyright and publisher restrictions when uploading content to the repository. http://www.swansea.ac.uk/library/researchsupport/ris-support/ 69 RICHARD PRICE AND THE HISTORY OF SCIENCE John V. Tucker Abstract Richard Price (1723–1791) was born in south Wales and practised as a minister of religion in London. He was also a keen scientist who wrote extensively about mathematics, astronomy, and electricity, and was elected a Fellow of the Royal Society. Written in support of a national history of science for Wales, this article explores the legacy of Richard Price and his considerable contribution to science and the intellectual history of Wales.
    [Show full text]
  • Cavendish the Experimental Life
    Cavendish The Experimental Life Revised Second Edition Max Planck Research Library for the History and Development of Knowledge Series Editors Ian T. Baldwin, Gerd Graßhoff, Jürgen Renn, Dagmar Schäfer, Robert Schlögl, Bernard F. Schutz Edition Open Access Development Team Lindy Divarci, Georg Pflanz, Klaus Thoden, Dirk Wintergrün. The Edition Open Access (EOA) platform was founded to bring together publi- cation initiatives seeking to disseminate the results of scholarly work in a format that combines traditional publications with the digital medium. It currently hosts the open-access publications of the “Max Planck Research Library for the History and Development of Knowledge” (MPRL) and “Edition Open Sources” (EOS). EOA is open to host other open access initiatives similar in conception and spirit, in accordance with the Berlin Declaration on Open Access to Knowledge in the sciences and humanities, which was launched by the Max Planck Society in 2003. By combining the advantages of traditional publications and the digital medium, the platform offers a new way of publishing research and of studying historical topics or current issues in relation to primary materials that are otherwise not easily available. The volumes are available both as printed books and as online open access publications. They are directed at scholars and students of various disciplines, and at a broader public interested in how science shapes our world. Cavendish The Experimental Life Revised Second Edition Christa Jungnickel and Russell McCormmach Studies 7 Studies 7 Communicated by Jed Z. Buchwald Editorial Team: Lindy Divarci, Georg Pflanz, Bendix Düker, Caroline Frank, Beatrice Hermann, Beatrice Hilke Image Processing: Digitization Group of the Max Planck Institute for the History of Science Cover Image: Chemical Laboratory.
    [Show full text]
  • Maty's Biography of Abraham De Moivre, Translated
    Statistical Science 2007, Vol. 22, No. 1, 109–136 DOI: 10.1214/088342306000000268 c Institute of Mathematical Statistics, 2007 Maty’s Biography of Abraham De Moivre, Translated, Annotated and Augmented David R. Bellhouse and Christian Genest Abstract. November 27, 2004, marked the 250th anniversary of the death of Abraham De Moivre, best known in statistical circles for his famous large-sample approximation to the binomial distribution, whose generalization is now referred to as the Central Limit Theorem. De Moivre was one of the great pioneers of classical probability the- ory. He also made seminal contributions in analytic geometry, complex analysis and the theory of annuities. The first biography of De Moivre, on which almost all subsequent ones have since relied, was written in French by Matthew Maty. It was published in 1755 in the Journal britannique. The authors provide here, for the first time, a complete translation into English of Maty’s biography of De Moivre. New mate- rial, much of it taken from modern sources, is given in footnotes, along with numerous annotations designed to provide additional clarity to Maty’s biography for contemporary readers. INTRODUCTION ´emigr´es that both of them are known to have fre- Matthew Maty (1718–1776) was born of Huguenot quented. In the weeks prior to De Moivre’s death, parentage in the city of Utrecht, in Holland. He stud- Maty began to interview him in order to write his ied medicine and philosophy at the University of biography. De Moivre died shortly after giving his Leiden before immigrating to England in 1740. Af- reminiscences up to the late 1680s and Maty com- ter a decade in London, he edited for six years the pleted the task using only his own knowledge of the Journal britannique, a French-language publication man and De Moivre’s published work.
    [Show full text]
  • Henry Cavendish Outline
    Ann Karimbabai Massihi Sveti Patel Sandy Saekoh Thomas Choe Chemistry 480 Dr. Harold Goldwhite Henry Cavendish I. Childhood A. Henry Cavendish was born in Nice, France, on 10 October1731, and died alone on 24 February 1810. B. His parental grandfather was Duke of Devonshire and his maternal grandfather was Duke of Kent 1 C. His parents were English aristocrats. D. His father was Lord Charles Cavendish, a member of Royal Society in London and an experimental scientist. E. His father made his own scientific equipment for him. II. Education A. At age of 11, he attended Dr. Newcome’s Academy in Hackney, London from 1749-1753. B. In 1749, he went to Peterhouse College. C. He left the college at 1753 without a degree. D. His father encouraged his scientific interest and introduced him to the Royal Society and he became a member in 1760. III. Papers A. Since he did his scientific investigation for his pleasure, he was careless in publishing the results. B. In 1776, he published his 1st paper about the existence of hydrogen as a substance. 1. He received the Copley Medal of the Royal Society for this achievement. C. In 1771, a theoretical study of electricity. D. In 1784, the synthesis of water. E. In 1798, the determination of the gravitational constant. IV. Experiments A. Fixed air (CO2) produced by mixing acids and bases. B. “Inflammable air” (hydrogen) generated by the action of acid on metals. 2 Figure 1. Cavendish's apparatus for making and collecting hydrogen Gas bladder used by Henry Cavendish 3 C.
    [Show full text]
  • Section 1 – Oxygen: the Gas That Changed Everything
    MYSTERY OF MATTER: SEARCH FOR THE ELEMENTS 1. Oxygen: The Gas that Changed Everything CHAPTER 1: What is the World Made Of? Alignment with the NRC’s National Science Education Standards B: Physical Science Structure and Properties of Matter: An element is composed of a single type of atom. G: History and Nature of Science Nature of Scientific Knowledge Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available. … In situations where information is still fragmentary, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest. Alignment with the Next Generation Science Standards Science and Engineering Practices 1. Asking Questions and Defining Problems Ask questions that arise from examining models or a theory, to clarify and/or seek additional information and relationships. Re-enactment: In a dank alchemist's laboratory, a white-bearded man works amidst a clutter of Notes from the Field: vessels, bellows and furnaces. I used this section of the program to introduce my students to the concept of atoms. It’s a NARR: One night in 1669, a German alchemist named Hennig Brandt was searching, as he did more concrete way to get into the atomic every night, for a way to make gold. theory. Brandt lifts a flask of yellow liquid and inspects it. Notes from the Field: Humor is a great way to engage my students. NARR: For some time, Brandt had focused his research on urine. He was certain the Even though they might find a scientist "golden stream" held the key.
    [Show full text]
  • The Conservatives in British Government and the Search for a Social Policy 1918-1923
    71-22,488 HOGAN, Neil William, 1936- THE CONSERVATIVES IN BRITISH GOVERNMENT AND THE SEARCH FOR A SOCIAL POLICY 1918-1923. The Ohio State University, Ph.D., 1971 History, modern University Microfilms, A XEROX Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED THE CONSERVATIVES IN BRITISH GOVERNMENT AND THE SEARCH FOR A SOCIAL POLICY 1918-1923 DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Neil William Hogan, B.S.S., M.A. ***** The Ohio State University 1971 Approved by I AdvAdviser iser Department of History PREFACE I would like to acknowledge my thanks to Mr. Geoffrey D.M. Block, M.B.E. and Mrs. Critch of the Conservative Research Centre for the use of Conservative Party material; A.J.P. Taylor of the Beaverbrook Library for his encouragement and helpful suggestions and his efficient and courteous librarian, Mr. Iago. In addition, I wish to thank the staffs of the British Museum, Public Record Office, West Sussex Record Office, and the University of Birmingham Library for their aid. To my adviser, Professor Phillip P. Poirier, a special acknowledgement#for his suggestions and criticisms were always useful and wise. I also want to thank my mother who helped in the typing and most of all my wife, Janet, who typed and proofread the paper and gave so much encouragement in the whole project. VITA July 27, 1936 . Bom, Cleveland, Ohio 1958 .......... B.S.S., John Carroll University Cleveland, Ohio 1959 - 1965 .... U.
    [Show full text]
  • Astronomy – Masonic Astronomers and Explorers
    Astronomy - Masonic Astronomers and Explorers ASTRONOMY - MASONIC ASTRONOMERS AND EXPLORERS R.J.Nairn, PM, Research Lodge of New South Wales No.971, UGLNSW Note: The names of known Masons are shown bold. Quotes are in italics Introduction In all three degrees of craft Masonry there are references to the importance of the study of the seven liberal arts and sciences. We are taught to make a daily advancement in our Masonic knowledge and, to assist us to do so, the seven liberal arts and sciences are defined as Grammar, Rhetoric, Logic, Arithmetic, Geometry, Music and Astronomy. This paper on astronomy focuses on the relevance of this science in our lives and in our Freemasonry today. It is illustrated by reference to famous Masonic astronomers and explorers. Thus the paper is not only intended to assist us in furthering our knowledge and understanding of the world around us but also to understand how some very famous Masons contributed to the way we live today. We are also interested in the extent to which Freemasonry interested them and stimulated their lives. Since time immemorial astronomy has been fundamental in helping us to find our location and direction. It provided the basis for telling the time and the period of the year. The sun was worshipped as the giver of life and today we recognise that its light is still an essential basis for photosynthesis in plant life. The moon helps us determine the tides for fishing and marine safety. The stars provided the symbolism for the mysticism of astrology and are today still being studies for evidence of life and our earliest beginnings.
    [Show full text]
  • Slides from These Events
    The wonderπ of March 14th, 2019 by Chris H. Rycroft Harvard University The circle Radius r Area = πr2 Circumference = 2πr The wonder of pi • The calculation of pi is perhaps the only mathematical problem that has been of continuous interest from antiquity to present day • Many famous mathematicians throughout history have considered it, and as such it provides a window into the development of mathematical thought itself Assumed knowledge 3 + = Hindu–Arabic Possible French origin Welsh origin 1st–4th centuries 14th century 16th century • Many symbols and thought processes that we take for granted are the product of millennia of development • Early explorers of pi had no such tools available An early measurement • Purchased by Henry Rhind in 1858, in Luxor, Egypt • Scribed in 1650BCE, and copied from an earlier work from ~ 2000BCE • One of the oldest mathematical texts in existence • Consists of fifty worked problems, the last of which gives a value for π Problem 24 (An example of Egyptian mathematical logic) A heap and its 1/7 part become 19. What is the heap? Then 1 heap is 7. (Guess an answer and see And 1/7 of the heap is 1. if it works.) Making a total of 8. But this is not the right answer, and therefore we must rescale 7 by the (Re-scale the answer to obtain the correct solution.) proportion of 19/8 to give 19 5 7 × =16 8 8 Problem 24 A heap and its 1/7 part become 19. What is the heap? • Modern approach using high-school algebra: let x be the size of the heap.
    [Show full text]
  • Modern Outlook on the Concept of Temperature Edward Bormashenko Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B
    What Is the Temperature? Modern Outlook on the Concept of Temperature Edward Bormashenko Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel ORCID id 0000-0003-1356-2486 Abstract The meaning and evolution of the notion of “temperature” (which is a key concept for the condensed and gaseous matter theories) is addressed from the different points of view. The concept of temperature turns out to be much more fundamental than it is conventionally thought. In particular, the temperature may be introduced for the systems built of “small” number of particles and particles in rest. The Kelvin temperature scale may be introduced into the quantum and relativistic physics due to the fact, that the efficiency of the quantum and relativistic Carnot cycles coincides with that of the classical one. The relation of the temperature to the metrics of the configurational space describing the behavior of system built from non-interacting particles is demonstrated. The Landauer principle asserts that the temperature of the system is the only physical value defining the energy cost of isothermal erasing of the single bit of information. The role of the temperature the cosmic microwave background in the modern cosmology is discussed. Keywords: temperature; quantum Carnot engine; relativistic Carnot cycle; metrics of the configurational space; Landauer principle. 1. Introduction What is the temperature? Intuitively the notions of “cold” and “hot” precede the scientific terms “heat” and “temperature”. Titus Lucretius Carus noted in De rerum natura that “warmth” and “cold” are invisible and this makes these concepts difficult for understanding [1]. The scientific study of heat started with the invention of thermometer [2].
    [Show full text]
  • Phyzguide: Weighing the Earth
    PhyzGuide: Weighing the Earth IN SEARCH OF “G” In 1665, 22 year-old Isaac Newton derived the law of universal gravitation. This law can be summarized by the equation that describes the gravitational force of attraction between any two masses. F = G Mm R2 Although Newton was able to verify the validity of the “inverse-square” nature of this formula through calculations involving the orbit of the moon, he was never able to determine the value of the constant G (the universal gravitation constant). The equation could only be used as the proportion F∝Mm/R2 until the value of G was determined. The problem in determining G was that in order to do so, you needed to know the gravitational force between two known masses separated by a known distance: 2 G = FR Mm One could easily determine the attraction between an object of known mass and the Earth by weighing it, but the mass of the Earth was not known during Newton’s lifetime. Before the end of the eighteenth century, however, the answer would be found! The Book of Phyz © Dean Baird. All rights reserved. 9/17/14 db THE CAVENDISH EXPERIMENT In 1798, Henry Cavendish devised an experiment to determine the value of G. Instead of involving the gravitational force exerted by the Earth, he measured the gravitational attraction between two known masses in his lab. Measuring this force was difficult because it was exceedingly small (about 10–9 N or 0.000 000 001 N). Cavendish was able to accurately measure this force by using a highly delicate torsion balance as shown below.
    [Show full text]