Mind's pearl

Facebook Twitter

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. The strings themselves make hardly any noise: they are thin and slip easily through the air without making much of disturbance - and a sound wave is a disturbance of the air.

The body The body serves to transmit the vibration of the bridge into vibration of the air around it. The air inside. 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. At the fixed end they add to give no motion - zero displacement: after all it is this condition of immobility which causes the inverted reflection. This is shown in the animation and the figure. 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

"Torsional waves in a bowed string" (2005, Acustica, 91, 241-246). It has sound files of the translational and rotational waves, an animation of idealised Helmholtz motion in translation and a brief summary of the paper. This figure, reproduced from the paper, shows the velocity, in time and frequency domain representation, of the transverse and torsional waves in a bass E string, bowed by an experienced string player. For comparison, the torsional wave is represented by rω, the product of the string radius and the angular velocity.

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. . [2] C. Music - Bitport.io. 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. 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! 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. If we can divide a number A by a number B, without remainder, we say that B is a factor or divisor of A, and that A is a multiple of B.

World of Mathematics

For example, 7 is a factor of 21, 4 is a factor of 20 and 60 is a multiple of 12. When thinking about number problems, it is often useful to find all the factors of a number. To do this, we should note that factors always appear in pairs. For example, 7 × 3 = 21, so 3 and 7 are a factor pair of 21. Let us write down these factor pairs, until we meet in the middle:

Articles

The Periodic Table of Videos - University of Nottingham. Find Your Name in the Periodic Table of the Elements. Top 10 Scientific Mnemonics. Humans.

Top 10 Scientific Mnemonics

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. Mardi 26 juin 2012 2 26 /06 /Juin /2012 02:33 10 techniques de manipulation de l'opinion publique et de la société 1.

10 techniques de manipulation de l'opinion publique et de la société

La stratégie de la diversion. Élément primordial du contrôle social, la stratégie de la diversion consiste à détourner l'attention du public des problèmes importants et des mutations décidées par les élites politiques et économiques, grâce à un déluge continuel de distractions et d'informations insignifiantes. La stratégie de la diversion est également indispensable pour empêcher le public de s'intéresser aux connaissances essentielles, dans les domaines de la science, de l'économie, de la psychologie, de la neurobiologie, et de la cybernétique. 2. 3. 5. 7. 8. 9. 10.

Le Petit Érudit. HowStuffWorks "Learn how Everything Works!".

La boite verte

Université Ouverte des Humanités: Le projet. 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. 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.

Ils achètent eux-mêmes toutes les marchandises qui les asservissent toujours un peu plus. Ils courent eux-mêmes derrière un travail toujours plus aliénant, que l’on consent généreusement à leur donner, s’ils sont suffisamment sages. Ils choisissent eux-mêmes les maitres qu’ils devront servir. Voilà le mauvais rêve des esclaves modernes qui n’aspirent finalement qu’à se laisser aller dans la danse macabre du système de l’aliénation.

L’oppression se modernise en étendant partout les formes de mystification qui permettent d’occulter notre condition d’esclave. Chapitre III : L’aménagement du territoire et l’habitat La Société du Spectacle, Guy Debord.

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. Le Béhémoth dans l'art et la littérature[modifier | modifier le code] Tour de Babel. Empire romain. Belzébuth. Language Exchange Community - Practice Foreign Languages. ¤ Portail des civilisations anciennes.

Does Language Influence Culture? Les expressions françaises décortiquées - Accueil. Fractale. Spheres. Spheres [ english | español | portugués ] Spherical Surface of Dialogue Spheres shaped by dialogue, a net of semantical combinations. 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. By: René Descartes (1596-1650) The Discourse on Method is best known as the source of the famous quotation “cogito ergo sum”, “I think, therefore I am.” ….

It is a method which gives a solid platform from which all modern natural sciences could evolve. With this work, the idea of skepticism was revived from the ancients such as Sextus Empiricus and modified to account for a truth that Descartes found to be incontrovertible. Descartes started his line of reasoning by doubting everything, so as to assess the world from a fresh perspective, clear of any preconceived notions.

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