Misconceptions

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Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Contrary to a widespread perception, the real number 0.999...—where the decimal point is followed by an infinite sequence of nines—is exactly equal to 1 by definition. They are two different ways of writing the same real number. A 2009 study by Weller et al. states that "Tall and Schwarzenberger (1978) asked first year university mathematics students whether 0.999... is equal to 1. The majority of the students thought that 0.999... is less than 1." Weller et al. go on to describe their own controlled experiment, performed "during the 2005 fall semester at a major research university in the southern United States. Pre-service elementary and middle school teachers from all five sections of a sophomore-level mathematics content course on number and operation participated in the study." The results are striking: "On the question of whether .999...=1, 72% of the control group and 83% of the experimental group expressed their view that .999... is not equal to 1."

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
The Coriolis effect does not determine the direction that water rotates in a bathtub drain or a flushing toilet. The Coriolis effect induced by the Earth's rotation becomes significant and noticeable only at large scales, such as in weather systems or oceanic currents. In addition, most toilets inject water into the bowl at an angle, causing a spin too fast to be significantly affected by the Coriolis effect.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Gyroscopic forces are not required for a rider to balance a bicycle. Although gyroscopic forces are a factor, the stability of a bicycle is determined primarily by inertia, steering geometry, and the rider's ability to counteract tilting by steering.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Another popular myth is that having sex in the days leading up to a sporting event or contest is detrimental to performance. Numerous studies have shown that there is no physiological basis to this myth. Additionally, it has been demonstrated that sex during the 24 hours prior to sports activity can elevate the levels of testosterone in males, which potentially could enhance their performance.

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Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Mental abilities are not absolutely separated into the left and right cerebral hemispheres of the brain. Some mental functions such as speech and language (cf. Broca's area, Wernicke's area) tend to activate one hemisphere of the brain more than the other, in some kinds of tasks. If one hemisphere is damaged at a very early age, however, these functions can often be recovered in part or even in full by the other hemisphere (see Neuroplasticity). Other abilities such as motor control, memory, and general reasoning are served equally by the two hemispheres.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Golgi-stained neurons in human hippocampal tissue. It is commonly believed that humans will not grow new brain cells, but research has shown that some neurons can reform in humans.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Until very recently medical experts believed that humans were born with all of the brain cells they would ever have. However, we now know that new neurons can be created in the postnatal brain. Researchers have observed adult neurogenesis in avians, Old World Primates, and humans. Adults of these species retain multipotent (see cell potency) neural stem cells in the subventricular zone of the lateral ventricles and subgranular zone of the dentate gyrus. The newborn neurons generated in these areas migrate to the olfactory bulb and the dentate gyrus, respectively, and are believed to integrate into existing neural circuits. However, the function and physiological significance of adult-born neurons remains unclear. Some studies have suggested that post-natal neurogenesis also occurs in the neocortex, an idea that is disputed.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
Vaccines do not cause autism. Fraudulent research by Andrew Wakefield claimed a connection. The results could not be reproduced. Subsequently the research was shown to be flawed and fraudulent.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
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. This myth has been commonplace in American culture at least as far back as the start of the 20th century, and was attributed to William James, who apparently used the expression metaphorically. Some findings of brain science (such as the high ratio of glial cells to neurons) have been mistakenly read as providing support for the myth.

in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
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.