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Pacer. How does a guitar work? Contents First, something about sound If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving.

How does a guitar work?

When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. At any point in the air near the source of sound, the molecules are moving backwards and forwards, and the air pressure varies up and down by very small amounts. The strings The pitch of a vibrating string depends on four things. Strings, standing waves and harmonics. The animation shows the interaction of two waves, with equal frequency and magnitude, travelling in opposite directions: blue to the right, green to the left.

Strings, standing waves and harmonics

The red line is their sum: the red wave is what happens when the two travelling waves add together (superpose is the technical term). By stopping the animation, you can check that the red wave really is the sum of the two interacting travelling waves. The figure at right is the same diagram represented as a time sequence - time increases from top to bottom. You could think of it as representing a series of photographs of the waves, taken very quickly.

The red wave is what we would actually see in a such photographs. Suppose that the right hand limit is an immoveable wall. Strong coupling of torsional and transverse waves in a bowed string. This page is an appendix for the scientific paper: Bavu, E., Smith, J. and Wolfe, J.

Strong coupling of torsional and transverse waves in a bowed string

Formulating Science in Terms of Possible and Impossible Tasks. David and I have been working on this together for the past three years, and we’ve been applying it to many different problems.

Formulating Science in Terms of Possible and Impossible Tasks

So far, the two completed parts of our trying out constructor theory to see whether it can solve problems are: a fundamental theory of information within physics1; and the constructor theory of life2, which applies this new theory of information to a fundamental problem that's at the boundary between physics and biology, and has to do with how certain features of living things, such as the ability to self-reproduce very accurately, are compatible with the laws of physics as we know them. In these two cases, you can see how switching to this new mode of explanation allows one to change the perspective and address the problems in a much more effective way. These are two examples where switching to this new mode of explanation makes all the difference. Take information, for example. One question might be how do you test constructor theory?

[1] D. Music - Brian Eno’s Reading List: 20 Essential Books for Sustaining Civilization. By Maria Popova Deconstructing a magnificent mind through his reading diet for intellectual survival.

Brian Eno’s Reading List: 20 Essential Books for Sustaining Civilization

UPDATE: The folks from the Long Now have kindly asked me to contribute to the Manual for Civilization library — here is my own reading list. There is something inescapably alluring about the reading lists of cultural icons, perhaps because in recognizing that creativity is combinatorial and fueled by networked knowledge, we intuitively long to emulate the greatness of an admired mind by replicating the bits and pieces, in this case the ideas found in beloved books, that went into constructing it.

Tons of Albert Einstein Documents Are Now Online for Free. Einstein Papers Project at Caltech. FLP Vol. I Table of Contents. The Feynman Lectures on Physics Vol. I Ch. 1: Atoms in Motion. 1–1Introduction This two-year course in physics is presented from the point of view that you, the reader, are going to be a physicist.

The Feynman Lectures on Physics Vol. I Ch. 1: Atoms in Motion

This is not necessarily the case of course, but that is what every professor in every subject assumes! If you are going to be a physicist, you will have a lot to study: two hundred years of the most rapidly developing field of knowledge that there is. So much knowledge, in fact, that you might think that you cannot learn all of it in four years, and truly you cannot; you will have to go to graduate school too! Surprisingly enough, in spite of the tremendous amount of work that has been done for all this time it is possible to condense the enormous mass of results to a large extent—that is, to find laws which summarize all our knowledge. Each piece, or part, of the whole of nature is always merely an approximation to the complete truth, or the complete truth so far as we know it. Now, what should we teach first? Bill Gates Favorite Books. Park East Press Even though Gates can get a meeting with almost anyone, he can't land a sit-down with Norman Borlaug, the late biologist and humanitarian who led the "Green Revolution" — a series of innovations that kept a huge chunk of humanity from starving.

Bill Gates Favorite Books

"Although a lot of people have never heard of Borlaug, he probably saved more lives than anyone else in history," Gates says. "It's estimated that his new seed varieties saved a billion people from starvation," many of whom were in India and Pakistan. Borlaug was awarded the Nobel Peace Prize, the Presidential Medal of Freedom, and the Congressional Gold Medal for his efforts — and is one of only seven people to do so. For Gates, Borlaug is a model in getting important work done in the world. Mozambook - les ebooks de littérature - ebooks of literature. OpenClassrooms, Le Site du Zéro - Les cours les plus ouverts du Web.

Graphisme & interactivité blog par Geoffrey Dorne. World of Mathematics.


The Periodic Table of Videos - University of Nottingham. Find Your Name in the Periodic Table of the Elements. Top 10 Scientific Mnemonics. Humans Science is full of long lists of important information that can be very difficult to remember.

Top 10 Scientific Mnemonics

A mnemonic is a small phrase or word that helps us to remember these things. This is a list of 10 mnemonics to help you learn some important scientific terms. This is to be the first in a series of lists of mnemonics. 10. Remember this phrase and when you want to know the speed of light, count the letters in each word of the sentence. To add up to. Sound Bottle : une bouteille qui remixe les sons aux alentours. 10 techniques de manipulation de l'opinion publique et de la société. Le Petit Érudit. HowStuffWorks "Learn how Everything Works!".

La boite verte

TED: Ideas worth spreading. Net Sommaire. De la servitude moderne - le livre. « Mon optimisme est basé sur la certitude que cette civilisation va s’effondrer.

de la servitude moderne - le livre

Mon pessimisme sur tout ce qu’elle fait pour nous entraîner dans sa chute. » La servitude moderne est une servitude volontaire, consentie par la foule des esclaves qui rampent à la surface de la Terre. Documentaires. Béhémoth. Un article de Wikipédia, l'encyclopédie libre.


Béhémoth, ou B'hemot (Bəhēmôth — hébreu : בהמות), est une créature mentionnée dans le Livre de Job, 40:15-24. Il est connu en arabe comme بهيموث (Bahīmoūth) ou بهموت (Bahamūt) . Le mot est la forme plurielle de (bəhēmāh : désigne en hébreu biblique les animaux domestiques, le bétail ; en arabe : بھيمة, bahimah, plur. بهائم, bahaëm), mais c'est un pluralis excellentiae, une méthode hébraïque pour exprimer la grandeur en « pluralisant » le nom (cf. Elohim), ce qui indique que le Béhémoth est la plus grande et puissante créature terrestre.

Métaphoriquement, le nom désigne toute bête de grande taille et/ou puissante. Tour de Babel. Un article de Wikipédia, l'encyclopédie libre. Pour les articles homonymes, voir Babel. Empire romain. Un article de Wikipédia, l'encyclopédie libre. Cet article traite d'une période de l'histoire de la Rome antique. Pour les territoires administrés par Rome, voir l'article Province romaine. Empire romain L'Empire fut fondé par Auguste, qui mit fin à la dernière guerre civile, dans la toute fin de la République romaine. Contrairement au régime républicain, qui était oligarchique, l'Empire fut une autocratie, tout en conservant durant le principat des apparences républicaines : le pouvoir politique était principalement détenu par un seul homme, l'empereur, qui s'appuya sur une bureaucratie sans cesse plus développée, sur une administration territoriale importante et sur un puissant appareil militaire.

En effet, à partir de la fin du IIe siècle, Rome est confrontée à ce que l'historiographie ultérieure a appelé les invasions barbares. Belzébuth. Un article de Wikipédia, l'encyclopédie libre. Belzébuth (Arabe : بعل الذباب, Ba‘al adh-Dhubāb ; Hébreu : בעל זבוב, Baʿal Zəbûb ; Grec : Βεελζεβούλ, Beelzeboúl ; Latin : Beelzebūb : Seigneur de tout ce qui vole) est un dieu païen du monde sémite vraisemblablement vénéré à Éqrôn (ou Accaron). Language Exchange Community - Practice Foreign Languages. ¤ Portail des civilisations anciennes. Does Language Influence Culture? Les expressions françaises décortiquées - Accueil. Fractale. Un article de Wikipédia, l'encyclopédie libre.

Ce terme était au départ un adjectif : les objets fractals (selon un pluriel formé sur l'exemple de "chantiers navals"). Les fractales sont définies de manière paradoxale, en référence aux structures gigognes dont ils constituent des cas particuliers : « Les objets fractals peuvent être envisagés comme des structures gigognes en tout point – et pas seulement en un certain nombre de points, les attracteurs de la structure gigogne classique. Cette conception hologigogne (gigogne en tout point) des fractales implique cette définition tautologique : un objet fractal est un objet dont chaque élément est aussi un objet fractal »[2].

Spheres. Spheres [ english | español | portugués ] Spherical Surface of Dialogue Spheres shaped by dialogue, a net of semantical combinations. The richness of words consists in their relations with one another. CALCULATRICE SCIENTIFIQUE EN LIGNE. Share Book Recommendations With Your Friends, Join Book Clubs, Answer Trivia. Ebooks libres et gratuits. Ebooks gratuits - Télécharger des revues et magazines en pdf gratuits. Free Audio Books - Download an audio book in mp3 or iPod format today! FILMS7 VOD - VIDEOS - CLIPS - BANDES DEMOS COMEDIENNES - VIDEO A LA DEMANDE - FILMS A VOIR EN LIGNE - CINEMA D'AUTEUR. Free Audio Book - Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences by René Descartes.

Shahi - A visual dictionary. Visual Thesaurus. Hugh Laurie - Tout est sous contrôle - Livre Audio[MU] sur megaupload dvdrip.