Pi and river length The number π is a mathematical constant that is the ratio of a circle's circumference to its diameter and is approximately equal to 3.14159.
Tuned pipe Scooter exhaust with expansion chamber and silencer On a two-stroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency History Expansion chambers were invented and successfully manufactured by Limbach, a German engineer, in 1938, to economize fuel in two stroke engines. Germany was running short of petrol, which was at that stage produced using coal and sewerage transformation. An unexpected bonus was that the two stroke engines using tuned exhausts produced far more power than if running with a normal silencer.
0.999... The repeating decimal continues with an infinite number of nines. In mathematics, the repeating decimal 0.999...
"Mystery" is a loosely-defined term for either unsolved problems (especially unsolved crimes) and for the (alleged) "paranormal". Please do not place articles here because a topic "has been described as" "a mystery". Category:Mysteries
Double bind A double bind is an emotionally distressing dilemma in communication in which an individual (or group) receives two or more conflicting messages, in which one message negates the other. This creates a situation in which a successful response to one message results in a failed response to the other (and vice versa), so that the person will automatically be wrong regardless of response. The double bind occurs when the person cannot confront the inherent dilemma, and therefore can neither resolve it nor opt out of the situation.
Corundum The name "corundum" is derived from the Tamil word kuruntam (குருந்தம்) meaning "ruby", and related to Sanskrit kuruvinda. In addition to its hardness, corundum is unusual for its density of 4.02 g/cm3, which is very high for a transparent mineral composed of the low atomic mass elements aluminium and oxygen.
A banana equivalent dose (abbreviated BED) is a unit of radiation exposure, defined as the additional dose a person will absorb from eating one banana. Banana equivalent dose
Clarke's Three Laws are three "laws" of prediction formulated by the British writer Arthur C. Clarke.
Siphonophorae Description Like other hydrozoans, certain siphonophores can emit light. A siphonophore of the genus Erenna has been discovered at a depth of around 1,600 meters (5,200 ft) off the coast of Monterey, California.
There are many theories about the nature and identity of Spring-heeled Jack. This urban legend was very popular in its time, due to the tales of his bizarre appearance and ability to make extraordinary leaps, to the point that he became the topic of several works of fiction. Spring Heeled Jack