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A map of Egypt. The ancient city of Syene is today known as Aswan. Taken from www.cia.gov/ library/publications/the-worldfactbook/maps/ maptemplate_eg.html.
Around 240 B.C., Eratosthenes made what is considered to be the most famous and accurate of the ancient measurements of the circumference of the Earth.1 It was accomplished by making presumably simultaneous measurements of the angles of the shadows cast by a vertical stick at Syene (today known as Aswan) and another at Alexandria, at noon on the da...
Depending on the rotational structure of Fresnel reflector, the rotation angle of the mirror was deduced under the eccentric condition. By analyzing the influence of the sun tracking rotation angle error caused by main factors, the change rule and extent of the influence were revealed. It is concluded that the tracking errors caused by the differen...
... El "experimento" de Eratóstenes ha sido discutido con largueza en la literatura didáctica [7,8,9,10] y no profundizaremos más en él ya que pertenece al acervo pedagógico universal. Se menciona hoy en la enseñanza de la geografía, la matemática, la astronomía y la física (a lo menos). ...
Two scientific events that significantly changed the face of our world are studied. They are the contribution of Eratosthenes and Columbus to the discovery of the earth roundness. They come together in an epistemological process leading to the formulation of a law of nature, as described. Didactical comments added, show that they can be usefully used in teaching practices.
... Since Eratosthenes' method for measuring the size of the Earth is relatively straight forward, it can be performed as a high school and university experiment without complicated or expensive equipment . The aim of the experiment described in this paper was to reproduce Eratosthenes' measurement in two countries separated by an ocean (Australia and New Zealand) and see if a value of comparable or better accuracy can be achieved. ...
Twenty-two hundred years ago, the Greek scientist Eratosthenes measured the circumference of the Earth. This paper describes an experiment to replicate Eratosthenes’ experiment with observers located in Australia and New Zealand. The most accurate circumference produced in the experiment described in this paper is 38 874 km, measured at Rosebud, Victoria, Australia, and Jimboomba, Queensland, Australia with an error of 2.9%. This exceeds the accuracy of Eratosthenes, although not of the modern recreation of his experiment between Syene and Alexandria. The experiment described in this paper might form a useful model for cooperation between schools in different countries.
To understand modern science as a coherent story, it is essential to recognize the accomplishments of the ancient Hindus. They invented our base-ten number system and zero that are now used globally, carefully mapped the sky and assigned motion to the Earth in their astronomy, developed a sophisticated system of medicine with its mind-body approach known as Ayurveda, mastered metallurgical methods of extraction and purification of metals, including the so-called Damascus blade and the Iron Pillar of New Delhi, and developed the science of self-improvement that is popularly known as yoga. Their scientific contributions made impact on noted scholars globally: Aristotle, Megasthenes, and Apollonius of Tyana among the Greeks; Al-Birūnī, Al-Khwārizmī, Ibn Labbān, and Al-Uqlīdisī, Al-Jāhiz among the Islamic scholars; Fa-Hien, Hiuen Tsang, and I-tsing among the Chinese; and Leonardo Fibbonacci, Pope Sylvester II, Roger Bacon, Voltaire and Copernicus from Europe. In the modern era, thinkers and scientists as diverse as Ralph Waldo Emerson, Johann Wolfgang von Goethe, Johann Gottfried Herder, Carl Jung, Max Müller, Robert Oppenheimer, Erwin Schrödinger, Arthur Schopenhauer, and Henry David Thoreau have acknowledged their debt to ancient Hindu achievements in science, technology, and philosophy. The American Association for the Advancement of Science (AAAS), one of the largest scientific organizations in the world, in 2000, published a timeline of 100 most important scientific finding in history to celebrate the new millennium. There were only two mentions from the non-Western world: (1) invention of zero and (2) the Hindu and Mayan skywatchers astronomical observations for agricultural and religious purposes. Both findings involved the works of the ancient Hindus. The Ancient Hindu Science is well documented with remarkable objectivity, proper citations, and a substantial bibliography. It highlights the achievements of this remarkable civilization through painstaking research of historical and scientific sources. The style of writing is lucid and elegant, making the book easy to read. This book is the perfect text for all students and others interested in the developments of science throughout history and among the ancient Hindus, in particular.
The Periplus of the Erythrean Sea is a description of trade networks in the western Indian Ocean written as a guide for merchants (Casson 1989: 5). This text provides a description, varying in detail, of a multitude of regions, including the geographic features, settlements, ports, and peoples to be found in each. The original text, dating to approximately 30–40 CE, no longer survives, but a copy, believed to date to the tenth century, has been preserved and is currently housed in Heidelberg (Graf 1994: 143). The southernmost location mentioned in the text is the port of Rhapta, on the East African coast. This port is also mentioned in Ptolemy’s Geography, a second-century CE geographical account, in which it is termed a mētropolis and located “a short distance from the sea” (mikron apothen thalassēs), that is, the mouth of the Rhaptos river which flowed into the Indian Ocean (4.7.12). The exact location of Rhapta has been the subject of a lengthy historical debate owing to a lack in the text of any description of recognizable geographic features associated with, and the absence of any notable archaeological sites that can unequivocally be attributed to, the port (Hoyle 1967: 95; Horton 1990: 97; Kirwan 1986: 99).
In this paper, we describe a lab activity for measuring a spherical balloon's circumference. The procedure we discuss is based on the method used by Eratosthenes to measure the Earth's circumference.