Science

In “You and Your Research”, Richard Hamming tells great scientists from ordinary ones

The Limits to Growth gives an opportunity to play with the fate of the world in the famous Club of Rome models.

Using Paul Falstad’s Math and Physics Applets, one can experiment with simple physical systems such as waves, or the harmonic oscillator in quantum mechanics.

The cutting Edge of popular science: cosmologists, molecular biologists, psychologists and computer scientists review their work in the book The Third Culture ; new interviews with scientists are added to the Edge about once per month.

Mathematics

A View from the Back of the Envelope helps to discover the world with approximate calculations: to compare the size of the Milky Way to earthly distances, to estimate orders of magnitude, calculate with powers of ten and know the length scales from atom to the Universe.

Among the geometrical games by Jeff Weeks are tic-tac-toe or billiards on the surface of torus (“doughnut”) or Klein bottle, and a flight simulator in curved spaces.

MathWorld is a constantly updated mathematics encyclopedia.

Physics

Units of Measurement is an explanatory dictionary of premetric units from around the world.

John Baez's Stuff: the world class mathematical physicist reviews diverse topics in physics (including open questions in physics) and mathematics; to young scientists, advice is given. Since 1993, he has written the column This Week's Finds in Mathematical Physics .

In the article “On the dimensionality of spacetime”, Max Tegmark shows that intelligent observers are unprobable in spacetimes with dimensions different from our 3+1.

Richard Feynman : The Douglas Robb Memorial Lectures : Streamed video are Feynman's sparkling popular scientific lectures on the interaction of electrons and light or quantum electrodynamics, the lectures that later became the book QED . Feynman makes complicated physics simple and show things from a surprising angle.

Usenet Physics FAQ gives answers to questions on general and particle physics, quantum mechanics, the theory of relativity and cosmology.

In the so-called many worlds' interpretation of quantum mechanics (The Everett Interpretation) everything that can happen, happens.

Beam Line is the magazine of the Stanford Linear Accelerator. It is not being published anymore, but the old issues are still worth reading — like the issue [PDF, 2.14 MiB, 55 pp.] devoted to the 100th anniversary of the discovery of the electron.

Chemistry

Chemistry: WebElements Periodic Table offers thorough information on the physical and chemical properties, and history of chemical elements.

Geology

The mineral and gemstone kingdom is a thorough handbook.

Psychology

Optical Illusions & Visual Phenomena by Michael Bach offers tens of visual illusions with explanations.

The fascinating article “There is no stream of consciousness” by Susan Blackmore draws implications on the nature on consciousness from discoveries in visual perception.

MIT professor Marvin Minsky has made available his articles on artificial intelligence, possible world views of other civilizations, and psychology.