physics and teaching
Get flash to fully experience Pearltrees
Liquid crystals are an interdisciplinary research area. Chemists are creating new materials and they are using the supramolecular system for synthesis, analysis and purifications of other materials. A special focus nowadays is the template synthesis of nanoscience materials, i.e. MCM-41. Biologist are studing the cell membrane as a liquid crystal with respect to intercellular transport (Endocytose, Exocytose, drug delivery) and communications.
Liquid Crystal Group Hamburg
With the general theory of relativity, in which Einstein managed to reconcile relativity and gravitation, he had to discard the traditional physics worldview, which saw space as merely a stage on which the events of the world unfold. Instead, space-time is a dynamic entity, which is distorted by any matter that is contained in it, and which in turn tells that matter how to move and evolve. This interaction between spacetime and matter is described by Einstein's geometric, relativistic theory of gravity. The consequences of that theory are spectacular.
General Relativity — Einstein Online
The SudoGlove is a gesture controller that can be easily interfaced with hardware or software via a wireless connection. The glove implements an array of sensors plus filtering circuitry and mathematical analysis firmware to derive state values for each sensor and transmits them to an authorized receiver. I have used the glove to drive an RC car, to synthesize music, to manipulate openGL video, to control arbitrary processing software, and to control performance lighting effects. You can see videos and examples of these interfaces below. A flex sensor mounted on the index finger is used to detect the curvature of the finger. Bending the sensor results in a change of resistance, which can be detected by the microcontroller.
SudoGlove Hardware Controller | JeremyBlum.com
Muslims Inventions in the Golden Age
Islamic Astronomy: Astronomical instruments Muslim astronomers developed a number of astronomical instruments, including several variations of the astrolabe, originally invented by Hipparchus in the 2nd century BCE, but with considerable improvements made to the device in the Muslim world. These instruments were used by Muslims for a variety of purposes related to astronomy, astrology, horoscopes, navigation, surveying, timekeeping, Qibla, Salah, etc. In the 10th century, al-Sufi first described over 1000 different uses of an astrolabe, including uses in astronomy, astrology, horoscopes, navigation, surveying, timekeeping, Qibla, Salah, etc. The Plate of Conjunctions, a computing instrument used to determine the time of day at which planetary conjunctions will occur,and for performing linear interpolation, invented by al-Kashi in the 15th century.
The following buttons will lead you on to a number of topics designed to help you understand more about mechanisms, basic engineering principles as well as designing and making your own automata and mechanical toys.
How to design automata and mechanical toys
Cams and Cranks
Learn how you can transmit power using Cams and Cranks are how these can be used to convert reciprocal to linear motion. Build 5 models including an oil drill, a flying eagle, a crane and a moving figure. A 36 page activity book is included with innovative experiments and detailed explanation of the different technological principles applied! Booklet with detailed building instructions also included. The set includes a 31 page, colorful, highly illustrated activity book which explains the science and applications of cams and cranks with the following chapters:
Policy & Advocacy ASTC's Office of Government Relations is your voice in Washington, DC, and represents your interests before the U.S. Congress, Executive Branch, and Federal agencies that provide support to science centers and museums. Learn More
Association of Science-Technology Centers
This circuit is an astable multivibrator , or oscillator . The two transistors are cross-coupled in such a way that the circuit switches back and forth between two states. In one state, the base of Q1 is about one diode drop above ground, allowing a base current to flow. This keeps Q1 switched on, in saturation mode, allowing a current to flow through the collector, keeping Q1's collector voltage low, and discharging C1.
Astable Multivibrator (Oscillator)
Semiconductor's Magnetic Movie written by Douglas Kahn : In 1744 a simple experiment was conducted in Sweden to reproduce the underlying cause of the Aurora Borealis in a laboratory, what we would now think of as a room. A small hole in a shade "the size of a large pea" let through a ray of sunlight that then was refracted through a prism. The small patch of light broken into a spectrum of colours then traveled through a medium of turbulent air directly above a warmed glass of aquavit. The resulting image landed on a screen a few short feet away and looked like what was seen dancing in the sky on many long Swedish nights, nature's sublime entertainment in the real pre-history of cinema. The experiment concluded that the aurora was caused by a refraction of light through volatile vapors.
Magnetic Movie
Cool Experiments with Magnets This web site is devoted to magnetism and the cool experiments you can do with permanent magnets and electro-magnets. Some of the experiments are very basic - things you've done since second grade.
Magnet Man - Cool Experiments with Magnets
Using a Laser to Measure the Speed of Light in Gelatin
Abstract Think it takes expensive, sophisticated equipment to measure the speed of light? Think again! Outfit yourself with a simple handheld laser pointer, a protractor, and gelatin, and you're ready to get started.Drawdio - a video
I've been taking video of people using drawdio for the last few weeks. Here's the compilation. I still don't have video of someone playing a song really well on it, though I've seen it happen.This book will guide you through the programming techniques for the PIC micro controllers, starting from the very beginning knowledge . This book has three sections: The Beginner's section, the Indeterminate and the Advanced section. Each section will has two parts: The first part is the theory and the second one it the practice .
PIC Pages - PCB Heaven
Keith's Think Zone
Keith Enevoldsen, Seattle, USA, EarthAn impressive homemade wall climbing system from a simple vacuum cleaner was created by a scientist from BBC. After being bitten by a radioactive spider, the mild-mannered Peter Parker in the Spiderman movies and comics finds himself able to climb up the side of buildings. The enterprising scientist Jem Stansfield got the same effect in real life from the two vacuum cleaners purchased at Tesco. From the video below, he demonstrated his Spiderman Prowess by climbing up the 120 feet front wall of BBC Television center as he documented his experience. The image below shows how he used the suction power of a modified vacuum cleaner motor to hold his weight on the wall.