Backreaction Home | Practical Physics This website is for teachers of physics in schools and colleges. It is a collection of experiments that demonstrate a wide range of physical concepts and processes. Some of the experiments can be used as starting-points for investigations or for enhancement activities. Physics is a practical science. Good quality, appropriate physics experiments and investigations are the key to enhanced learning, and clarification and consolidation of theory. We have published a new set of resources to support the teaching of practical science for Key Stages 3-5.
Teach Yourself Logic: A Study Guide, and other book notes Most philosophy departments, and many maths departments too, teach little or no serious logic, despite the centrality of the subject. Many students will therefore need to teach themselves, either solo or by organizing study groups. But what to read? Students need annotated reading lists for self-study, giving advice about the available texts. The main Guide and its Appendix are in PDF form, designed for on-screen reading. Teach Yourself Logic 2105: A Study Guide (PDF, iv + 94 pp.) If the Guide’s length makes it sound daunting, there are also some supplementary webpages which might help ease your way in: About the Guide Is the Guide for you? And here are some additional webpages: It goes without saying, of course, that all constructive comments and suggestions continue to be most warmly welcomed.
General Relativity (Fall, 2012) 1 The equivalence principle and tensor analysis The principle of equivalence of gravity and acceleration, or gravitational and inertial mass is the fundamental basis of general relativity. This was Einstein's key insight. Professor Susskind begins the first lecture of the course with Einstein'...
Not Even Wrong Graham Farmelo has posted a very interesting interview he did with Witten last year, as part of his promotion of his forthcoming book The Universe Speaks in Numbers. One surprising thing I learned from the interview is that Witten learned Calculus when he was 11 (this would have been 1962). He quite liked that, but then lost interest in math for many years, since no one gave him more advanced material to study. If only back in 1962 someone had told Witten about linear algebra and quantum mechanics, the entire history of the subject could have been quite different. A lesson for all parents: if your child is an off-the-scale genius, learning Calculus at age 11, don’t even think about trying to give them a normal childhood. I did though find some of the later parts of the interview quite depressing. Looking to the near future, he’s most optimistic about the “It from Qubit” business. Update: As explained in the comments, the advice to parents was not meant to be taken seriously.
PhysicsCentral: Learn How Your World Works Top Free eBooks Cosmology (Winter, 2013) 1 The expanding (Newtonian) universe Professor Susskind introduces the topic of modern Cosmology, which started with the discovery of cosmic microwave background radiation in 1964. However, this lecture focuses on the classical or Newtonian view of the universe. Beginning with the... [more] 2 Matter and radiation dominated universes After reviewing the basic equation for an expanding universe, Professor Susskind solves the equation explicitly for a zero energy universe, and then extends the derivation to universes with non-zero energy. These universes can take two forms:... [more] 3 Geometries of space: flat, spherical, hyperbolic Professor Susskind presents three possible geometries of homogeneous space: flat (infinite), spherical (positively curved and finite), hyperbolic (negatively curved and infinite).
Recent Physics of the Dark Universe Articles Recently published articles from Physics of the Dark Universe. EURECA Conceptual Design Report The EURECA Collaboration Available online 4 April 2014G. Angloher | E. The EURECA (European Underground Rare Event Calorimeter Array) project is aimed at searching for dark matter particles using cryogenic bolometers. Cold dark matter halos in Multi-coupled Dark Energy cosmologies: Structural and statistical properties April 2014Marco Baldi The recently proposed Multi-coupled Dark Energy (McDE) scenario – characterised by two distinct cold dark matter (CDM) particle species with opposite couplings to a Dark Energy scalar field – introduces... Virtual gravitational dipoles: The key for the understanding of the Universe? April 2014Dragan Slavkov Hajdukovic Before the end of this decade, three competing experiments (ALPHA, AEGIS and GBAR) will discover if atoms of antihydrogen fall up or down. A way forward for Cosmic Shear: Monte-Carlo Control Loops April 2014Alexandre Refregier | Adam Amara
Chapter 3 Classical physics could not explain the spectra of black bodies. It predicted that the intensity (power emitted at a given wavelength) of emitted light should increase rapidly with decreasing wavelength without limit (the "ultraviolet catastrophe"). In the figure below, the curve labeled "Rayleigh-Jeans law" shows the classically expected behavior. However, the measured spectra actually showed an intensity maximum at a particular wavelength, while the intensity decreased at wavelengths both above and below the maximum. E = hf (Planck's formula) where h (Planck's constant) is an exceedingly small number whose value we do not need here, and f is the frequency of vibration of the oscillator (the number of times it vibrates per second). Also in the late 1800s, experimental physicists were measuring the emission of electrons from metallic objects when they shined light on the object. 3.2. Line spectra are another example of phenomena that could not be explained by classical physics. l=h/p