Common Scientific Myths -- Physics

Physics

-------------------------------

• Gyroscopic forces are not required for a rider to balance a bicycle. However, the stability of a bicycle is improved by gyroscopic forces as well as by its geometry and the rider's ability to counteract tilting by steering.
• An illustration of the equal transit-time fallacy.It is not true that air takes the same time to travel above and below an aircraft's wing. This misconception, illustrated at right, is widespread among textbooks and non-technical reference books, and even appears in pilot training materials.
• Further information: equal transit-time fallacy, list of works with the equal transit-time fallacy, and lift (force)· Putting a teaspoon in the neck of an opened bottle of champagne will not help it retain its fizz. The misconception may arise from the fact that few people have two bottles of champagne open and unfinished at the same time to perform an accurate comparison[124] and likely suffer from subjective validation bias.
• Glass is not a high-viscosity liquid at room temperature: it is an amorphous solid, although it does have some chemical properties normally associated with liquids. Panes of stained glass windows often have thicker glass at the bottom than at the top, and this has been cited as an example of the slow flow of glass over centuries. However, this unevenness is due to the window manufacturing processes used in earlier eras, which produced glass panes that were unevenly thick at the time of their installation. It is not uncommon to find old windows that are thicker at the sides or the top.
• In the context of sunburn prevention, it is often claimed that 80% of sunburn-inducing UV-B passes through an overcast. Actually, based on the analysis used by the United States National Weather Service to develop the UV index, a "standard" solid overcast only transmits approximately 30% of UV-B, rather than 80%, although this certainly varies depending on many factors.
• Air is mostly nitrogen, not oxygen. Dry air contains roughly (by volume) 78% nitrogen, 21% oxygen, 0.93% argon, 0.038% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.