Common misconceptions

In ancient Rome, Romans did not build rooms called vomitoria in which to purge themselves after a meal. Vomitoria were the entranceways through which crowds entered and exited a stadium.

The notion that goldfish have a memory span of just a few seconds is false.

Italian dictator Benito Mussolini did not “make the trains run on time”. Much of the repair work had been performed before Mussolini and the Fascists came to power in 1922. Accounts from the era also suggest that the Italian railways’ legendary adherence to timetables was more myth than reality. Mussolini’s trains were subject to frequent labour disruptions due to his conflict with labour unions.

Searing meat does not “seal in” moisture, and in fact may actually cause meat to lose moisture. Generally, the value in searing meat is that it creates a brown crust with a rich flavor via the Maillard reaction.

Shaving does not cause terminal hair to grow back thicker or coarser or darker. This belief is because hair that has never been cut has a tapered end, whereas, after cutting, there is no taper. Thus, it appears thicker, and feels coarser due to the sharper, unworn edges. The fact that shorter hairs are “harder” (less flexible) than longer hairs also contributes to this effect. Hair can also appear darker after it grows back because hair that has never been cut is often lighter due to sun exposure.

Lemmings do not engage in mass suicidal dives off cliffs when migrating. They will, however, occasionally unintentionally fall off cliffs when venturing into unknown territory, with no knowledge of the boundaries of the environment. This misconception was popularized by the Disney film White Wilderness, which shot many of the migration scenes (also staged by using multiple shots of different groups of lemmings) on a large, snow-covered turntable in a studio. Photographers later pushed the lemmings off a cliff. The misconception itself is much older, dating back to at least the late nineteenth century.

It is commonly claimed that the Great Wall of China is the only man-made object visible from the Moon. This is false. None of the Apollo astronauts reported seeing any specific man-made object from the Moon, and even earth-orbiting astronauts can barely see it, but city lights are easily visible on the night side of Earth from orbit.

Seasons are not caused by the Earth being closer to the Sun in the summer than in the winter. In fact, the Earth is actually farther from the Sun when it is summer in the Northern Hemisphere. Seasons are the result of the Earth being tilted on its axis by 23.5 degrees. As the Earth orbits the Sun, different parts of the world receive different amounts of direct sunlight. When an area of the Earth’s surface is oriented perpendicular to the incoming sunlight, it will receive more radiation than it will when it is oriented at an angle to the incoming sunlight. In July, the Northern Hemisphere is tilted towards the Sun giving longer days and more direct sunlight; in January, it is tilted away. The seasons are reversed in the Southern Hemisphere, which is tilted towards the Sun in January and away from the Sun in July. In tropical areas of the world, there is no noticeable change in the amount of sunlight.

The word “jihad” does not always mean “holy war”; literally, the word in Arabic means “struggle”. While there is such a thing as “jihad bil saif”, or jihad “by the sword”, many modern Islamic scholars usually say that it implies an effort or struggle of a spiritual kind.

According to urban myth, the daddy longlegs spider (Pholcus phalangioides) is the most venomous spider in the world, but the shape of their mandibles leaves them unable to bite humans, rendering them harmless to our species. In reality, they can indeed pierce human skin, though the tiny amount of venom they carry causes only a mild burning sensation for a few seconds.

Thomas Crapper did not invent the flush toilet; it was invented by Sir John Harrington in 1596. Crapper, however, did much to increase its popularity and came up with some related inventions, such as the ballcock mechanism used to fill toilet tanks. He was noted for the quality of his products and received several Royal Warrants. He was not the origin of the word crap, but his name may have helped popularize it.

Vaccines do not cause autism. Although fraudulent research by Andrew Wakefield claimed a connection, repeated attempts to reproduce the results ended in failure, and the research was ultimately shown to be flawed and fraudulent.

Those suffering from flu or cold congestion do not need to avoid dairy because it does not increase mucus production. Drinking milk and/or consuming other dairy products does not increase mucus production.

A penny dropped from the Empire State Building will not kill a person or crack the sidewalk. Due to terminal velocity the speed of a falling penny cannot exceed 30–50 miles per hour regardless of the distance from which it is dropped.

Common misconception says that Noah was told in the Book of Genesis to bring two of every animal onto his ark. In the book, at Genesis 7:2, he is actually told to bring “seven pairs of every kind of clean animal […] and one pair of every kind of unclean animal”

The notion of catharsis holds that frustration and anger should not be bottled up or else a person risks allowing those feelings to accrue and eventually explode in some harmful way. Instead, it recommends that frustration and anger should be released through harmless expression, such as by screaming or punching a pillow. However, experimental psychology has shown that such expression can increase rather than decrease harmful behavior. In one experiment, people who engaged in catharsis (by hitting a punching bag) were significantly more likely to aggress toward a peer shortly afterward than were people who did not engage in catharsis.

Toilet waste is never intentionally dumped overboard from an aircraft. All waste is collected in tanks which are emptied on the ground by special toilet waste vehicles. A vacuum is used to allow the toilet to be flushed with less water and because plumbing cannot rely on gravity alone in an aircraft in motion. The infamous blue ice is caused by accidental leakages from the waste tank. Passenger trains, on the other hand, have historically flushed onto the tracks; however, modern trains usually have retention tanks on board the train.

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All taken from here, where there are many, many more.

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