Thursday, March 10, 2011

List of common misconceptions (Part 2 of 2)

Poinsettias are not highly toxic. It is true that they are mildly irritating to the skin or stomach and may sometimes cause diarrhea and vomiting if eaten.

It is not harmful to baby birds to pick them up and return them to their nests, despite the common belief that doing so will cause the mother to reject them.

Bulls are not enraged by the color red, used in capes by professional matadors. Cattle are dichromats, so red does not stand out as a bright color. It is not the color of the cape that angers the bull, but rather the movement of the fabric that irritates the bull and incites it to charge.

According to the California Academy of Sciences, around 41% of U.S. adults mistakenly believe humans and dinosaurs coexisted. However, the last of the dinosaurs died around 65 million years ago, after the Cretaceous–Tertiary extinction event, whereas the earliest Homo genus (humans) evolved between 2.3 and 2.4 million years ago.

Glass manufacturing in older eras was a slower process, which often resulted in unevenness and impurities when finished in its solid state. Varying thickness throughout older window panes is the result of these impurities, not due to movement of the glass over time. Glass is not a high-viscosity liquid at room temperature: it is an amorphous solid.

Different tastes can be detected on all parts of the tongue by taste buds, with slightly increased sensitivities in different locations depending on the person, contrary to the popular belief that specific tastes only correspond to specific mapped sites on the tongue.

There are not 4 but 5 primary tastes. In addition to bitter, sour, salty, and sweet, humans have taste receptors for umami, which is a savory or meaty taste.

Humans have more than five senses. Although definitions vary, the actual number ranges from 9 to more than 20. In addition to sight, smell, taste, touch, and hearing, which were the senses identified by Aristotle, humans can sense balance and acceleration (equilibrioception), pain (nociception), body and limb position (proprioception or kinesthetic sense), and relative temperature (thermoception). Other senses sometimes identified are the sense of time, itching, pressure, hunger, thirst, fullness of the stomach, need to urinate, need to defecate, and blood carbon dioxide levels.

Shaving does not cause terminal hair to grow back thicker or coarser or darker.

Hair and fingernails do not continue to grow after a person dies. Rather, the skin dries and shrinks away from the bases of hairs and nails, giving the appearance of growth.

Hair care products cannot as such "repair" split ends and damaged hair. They can, however, prevent damage from occurring in the first place, smooth down the cuticle in a glue-like fashion so that it appears repaired and generally make hair appear in better condition.

Sugar does not cause hyperactivity in children. Double-blind trials have shown no difference in behavior between children given sugar-full or sugar-free diets, even in studies specifically looking at children with attention-deficit/hyperactivity disorder or those considered sensitive to sugar.

Alcohol does not make one warmer. The reason that alcoholic drinks create the sensation of warmth is that they cause blood vessels to dilate and stimulate nerve endings near the surface of the skin with an influx of warm blood. This can actually result in making the core body temperature lower, as it allows for easier heat exchange with a cold external environment.

Alcohol does not kill brain cells. In fact, alcohol has positive health benefits when used moderately and new brain cells are generated on a daily basis.

People do not use only ten percent of their brains. While it is true that a small minority of neurons in the brain are actively firing at any one time, the inactive neurons are important too.

Waking sleepwalkers does not harm them. While it is true that a person may be confused or disoriented for a short time after awakening, this does not cause them further harm. In contrast, sleepwalkers may injure themselves if they trip over objects or lose their balance while sleepwalking.

Eating less than an hour before swimming does not increase the risk of experiencing muscle cramps or drowning.

The Coriolis effect does not determine the direction that water rotates in a bathtub drain or a flushing toilet. Most toilets inject water into the bowl at an angle, causing a spin too fast to be significantly affected by the Coriolis effect.

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.

Photographic or eidetic memory refers to the ability to remember images with extremely high precision – so high as to mimic a camera. However, it is highly unlikely that photographic memory exists, as to date there is no hard scientific evidence that anyone has ever had it.

Book of GenesisThe forbidden fruit mentioned in the Book of Genesis is commonly assumed to be an apple, and is widely depicted as such in Western art, although the Bible does not identify what type of fruit it is.

The historical Buddha was not obese. The "chubby Buddha" or "laughing Buddha" is a tenth century Chinese folk hero by the name of Budai.

The Immaculate Conception is not synonymous with the virgin birth of Jesus, nor is it a supposed belief in the virgin birth of Mary, his mother. Rather, the Immaculate Conception is the Roman Catholic belief that Mary was not subject to original sin from the first moment of her existence, when she was conceived.

George Washington Carver did not invent peanut butter, though he reputedly discovered three hundred uses for peanuts and hundreds more for soybeans, pecans, and sweet potatoes.

Thomas Edison did not invent the light bulb.

Henry Ford did not invent either the automobile or the assembly line. He did help to develop the assembly line substantially, sometimes through his own engineering but more often through sponsoring the work of his employees.

Guglielmo Marconi did not invent radio, but only modernized it for public broadcasting and communication. No single person was responsible for the invention of radio.

The United States Interstate Highway System was not designed with airplane landings in mind. A common urban legend states that one out of every five (or ten) miles of highway must be straight and flat to allow emergency (or military) airplane landings, but this is not the case.

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. Passenger trains, on the other hand, have historically flushed onto the tracks; however, modern trains usually have retention tanks on board the train.