02 MAR 2019 by ideonexus

## Triangles on Earth Exceed 180 Degrees

The idea that space and time can be curved or warped is fairly recent. For more than 2,000 years the axioms of Euclidean geometry were considered to be selfevident. As those of you who were forced to learn geometry at school may remember, one of the consequences of these axioms is that the angles ot a triangle add up to 180 degrees. However, in the last century people began to realise that other forms of geometry were possible in which the angles of a triangle need not add up to i8o degrees...
Folksonomies: perception curved space
Folksonomies: perception curved space

04 NOV 2018 by ideonexus

## Dice Rolls are Suspect

It is true that every aspect of the role of dice may be suspect: the dice themselves, the form and texture of the surface, the person throwing them. If we push the analysis to its extreme, we may even wonder what chance has to do with it at all. Neither the course of the dice nor their rebounds rely on chance; they are governed by the strict determinism of rational mechanics. Billiards is based on the same principles, and it has never been considered a game of chance. So in the final analysis...
Folksonomies: games randomness
Folksonomies: games randomness

10 MAR 2017 by ideonexus

## Gamification Memory Mechanic

In Memory games, the action of the game has some element that is dependent on players’ memory. This is simple and straightforward enough on its surface, but it becomes interestingly complex when examined in greater detail. What particular parts of memory are being tasked by the game? Some games ask the player to memorize and recall specific details or patterns. Others call on memories that a player brings into the game from his or her actual life. Still other memory games ask players not on...
Folksonomies: education gamification
Folksonomies: education gamification

31 MAY 2015 by ideonexus

## Flatland

Imagine a vast sheet of paper on which straight Lines, Triangles, Squares, Pentagons, Hexagons, and other figures, instead of remaining fixed in their places, move freely about, on or in the surface, but without the power of rising above or sinking below it, very much like shadows—only hard with luminous edges—and you will then have a pretty correct notion of my country and countrymen. Alas, a few years ago, I should have said "my universe:" but now my mind has been opened to higher views...

31 MAY 2015 by ideonexus

## Flatland Science: Dimensions

What and where is Flatland? A Square gives us several interesting answers, many of th contradictory. We know that it’s flat, big (but how big?), and very thin, the most important question of all is “how thin?” A lot depends on the answer… A Square himself eliminates the version that’s easiest for three-dimensional readers to understand; a world that’s thin – maybe only a few atoms thick - but nevertheless has some physical height. It would have some sort of solid or semi-solid ...
Folksonomies: science fiction otherness
Folksonomies: science fiction otherness

07 MAR 2015 by ideonexus

## Biocides

These sprays, dusts, and aerosols are now applied almost universally to farms, gardens, forests, and homes—non-selective chemicals that have the power to kill every insect, the "good" and the "bad," to still the song of birds and the leaping of fish in the streams, to coat the leaves with a deadly film, and to linger on in the soil—all this though the intended target may be only a few weeds or insects. Can anyone believe it is possible to lay down such a barrage of poisons on the surface ...
Folksonomies: environmentalism
Folksonomies: environmentalism

24 JAN 2015 by ideonexus

## Hawking's Equation

awking has written down an equation which looks rather like Planck's equation. Hawking's equation is S = kA, where S is the entropy of a black hole, A is the area of its surface, and k is a constant which I call Hawking's constant. Entropy means roughly the same thing as the heat capacity of an object. It is measured in units of calories per degree. A is measured in square centimeters. Hawking's equation says that entropy is really the same thing as area. The exchange rate between area and en...
Folksonomies: physics equation
Folksonomies: physics equation

11 JUN 2012 by ideonexus

## The Relationship Between Geology and Geography

All that comes above the surface [of the globe] lies within the province of Geography; all that comes below that surface lies inside the realm of Geology. The surface of the earth is that which, so to speak, divides them and at the same time 'binds them together in indissoluble union.' We may, perhaps, put the case metaphorically. The relationships of the two are rather like that of man and wife. Geography, like a prudent woman, has followed the sage advice of Shakespeare and taken unto her '...
Folksonomies: geology geography
Folksonomies: geology geography

They are intertwined, but there are strict boundaries.

04 JUN 2012 by ideonexus

## The Physics of Black Hole Creation

Let me describe briefly how a black hole might be created. Imagine a star with a mass 10 times that of the sun. During most of its lifetime of about a billion years the star will generate heat at its center by converting hydrogen into helium. The energy released will create sufficient pressure to support the star against its own gravity, giving rise to an object with a radius about five times the radius of the sun. The escape velocity from the surface of such a star would be about 1,000 kilom...
Folksonomies: physics black hole
Folksonomies: physics black hole

At a point in the star's collapse, it's escape velocity exceeds the speed of light.

16 MAY 2012 by ideonexus

## Physics Reduced to Probability

Philosophers have said that if the same circumstances don't always produce the same results, predictions are impossible and science will collapse. Here is a circumstance—identical photons are always coming down in the same direction to the piece of glass—that produces different results. We cannot predict whether a given photon will arrive at A or B. All we can predict is that out of 100 photons that come down, an average of 4 will be reflected by the front surface. Does this mean that phy...
Folksonomies: complexity probability
Folksonomies: complexity probability

Feynman explains that probabilities are the best we can hope for in complex systems.