Match Stick Rocket
Match Stick Rocket SUBJECT: Rocketry TOPIC: Propulsion
Gravitation
Gravitation, or gravity, is a natural phenomenon by which all physical bodies attract each other. It is most commonly recognized and experienced as the agent that gives weight to physical objects, and causes physical objects to fall toward the ground when dropped from a height. During the grand unification epoch, gravity separated from the electronuclear force. Gravity is the weakest of the four fundamental forces, and appears to have unlimited range (unlike the strong or weak force).
What Is Science? From Feynman to Sagan to Asimov to Curie, an Omnibus of Definitions
by Maria Popova “The most beautiful experience we can have is the mysterious — the fundamental emotion which stands at the cradle of true art and true science.” “We live in a society absolutely dependent on science and technology,” Carl Sagan famously quipped in 1994, “and yet have cleverly arranged things so that almost no one understands science and technology. That’s a clear prescription for disaster.”

Brief Answers to Cosmic Questions
Structure of the Universe Does the Universe have an edge, beyond which there is nothing? Are the galaxies arranged on the surface of a sphere? Why can't we see the whole universe?
Elementary Concepts in Statistics
In this introduction, we will briefly discuss those elementary statistical concepts that provide the necessary foundations for more specialized expertise in any area of statistical data analysis. The selected topics illustrate the basic assumptions of most statistical methods and/or have been demonstrated in research to be necessary components of our general understanding of the "quantitative nature" of reality (Nisbett, et al., 1987). We will focus mostly on the functional aspects of the concepts discussed and the presentation will be very short. Further information on each of the concepts can be found in statistical textbooks. Recommended introductory textbooks are: Kachigan (1986), and Runyon and Haber (1976); for a more advanced discussion of elementary theory and assumptions of statistics, see the classic books by Hays (1988), and Kendall and Stuart (1979).

Physics envy
In science, the term physics envy is used to criticize a tendency (perceived or real) of softer sciences and liberal arts to try to obtain mathematical expressions of their fundamental concepts, as an attempt to move them closer to harder sciences, particularly physics. Evolutionary biologist Ernst Mayr discusses the issue of the inability to reduce biology to its mathematical basis in his book What Makes Biology Unique?.[2] Noam Chomsky discusses the ability and desirability of reduction to its mathematical basis in his article "Mysteries of Nature: How Deeply Hidden
Einstein field equations
The Einstein field equations (EFE) or Einstein - Hilbert equations are a set of 10 equations in Albert Einstein's general theory of relativity which describe the fundamental interaction of gravitation as a result of spacetime being curved by matter and energy.[1] First published by Einstein in 1915[2] as a tensor equation, the EFE equate local spacetime curvature (expressed by the Einstein tensor) with the local energy and momentum within that spacetime (expressed by the stress–energy tensor).[3] As well as obeying local energy-momentum conservation, the EFE reduce to Newton's law of gravitation where the gravitational field is weak and velocities are much less than the speed of light.[4] Exact solutions for the EFE can only be found under simplifying assumptions such as symmetry. Special classes of exact solutions are most often studied as they model many gravitational phenomena, such as rotating black holes and the expanding universe.

Philip Zimbardo: The Secret Powers of Time (Animated)
Bio Philip Zimbardo Philip Zimbardo is internationally recognized as a leading "voice and face of contemporary psychology" through his widely seen PBS-TV series, "Discovering Psychology," his media appearances, best-selling trade books on shyness, and his classic research, The Stanford Prison Experiment. Zimbardo has been a Stanford University professor since 1968 (now an Emeritus Professor), having taught previously at Yale, NYU, and Columbia University.

Quadratic Equations: Quadratic Formula
Consider the general quadratic equation with . First divide both sides of the equation by a to get which leads to
Alcubierre Warp Drive Time Travel
An Alcubierre Warp Drive stretches spacetime in a wave causing the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship can ride the wave to accelerate to high speeds and time travel. The Alcubierre drive, also known as the Alcubierre metric or Warp Drive, is a mathematical model of a spacetime exhibiting features reminiscent of the fictional "warp drive" from Star Trek, which can travel "faster than light" (although not in a local sense - see below).

Friedmann equations
and pressure . The equations for negative spatial curvature were given by Friedmann in 1924.[2] Assumptions[edit]
Graphs Of Wikipedia: Influential Thinkers
The internet is big — very big. One such way to investigate all of this free online content is through graphs. The network visualisations by Simon Raper in his fantastic post about graphing the history of philosophy is one example of how to exploit such data. Let’s take this a step further and create a series of graphs using everyone on Wikipedia.