Zener cards are cards used to conduct experiments for extrasensory perception (ESP). Perceptual psychologist Karl Zener (1903–1964) designed the cards in the early 1930s for experiments conducted with his colleague, parapsychologist J. B. Rhine (1895–1980). Overview The Zener cards are a deck of 25 cards, five of each symbol. The five symbols are: a hollow circle, a plus sign, three vertical wavy lines, a hollow square, and a hollow five-pointed star.In a test for ESP, the experimenter picks up a card in a shuffled pack, observes the symbol, and records the answer of the person being tested, who would guess which of the five designs is on the card. The experimenter continues until all the cards in the pack are tested. This was featured in the 1984 film Ghostbusters. Poor shuffling methods can make the order of cards in the deck easier to predict and the cards could have been inadvertently or intentionally marked and manipulated. In his experiments, J. B. Rhine first shuffled the cards by hand but later decided to use a machine for shuffling.In his book, The New Apocrypha, John Sladek expressed...

Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is named in contrast with current electricity, where the electric charge flows through an electrical conductor or space, and transmits energy.A static electric charge can be created whenever two surfaces contact and or slide against each other and then separated. The effects of static electricity are familiar to most people because people can feel, hear, and even see the spark as the excess charge is neutralized when brought close to an electrical conductor (for example, a path to ground), or a region with an excess charge of the opposite polarity (positive or negative). The familiar phenomenon of a static shock – more specifically, an electrostatic discharge – is caused by the neutralization of a charge. Causes Materials are made of atoms that are normally electrically neutral because they contain equal numbers of positive charges (protons in their nuclei) and negative charges (electrons...

In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium.For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through matter, energy is preserved but entropy increases. This change in the matter's properties manifests...