Monday, July 14, 2014

10 Common Science Myths That Most People Believe (Part 2)

10 Common Science Myths That Most People Believe

continued from part 1

6. Dropping a penny from a tall building will kill someone.
If you were to head to the top of the Empire State Building (hopefully after it’s done being bombarded with lightning) and fling a penny down to the sidewalk below, it won’t kill anyone. Pennies are fairly lightweight at around one gram and being a flat circle doesn’t bode well in terms of aerodynamics. Because it would tumble and flip the entire way down, its low mass and relatively low terminal velocity (105 km/h) wouldn’t do much damage to the bystander on the sidewalk. It would feel similar to getting flicked in the head. Annoying, yes; but not lethal.
However, throwing items down to the ground that are more massive or more aerodynamic would increase the object’s terminal velocity and could do quite a bit of damage. Construction zones require hardhats in order to protect workers from stray rocks or bolts that are accidentally dropped from great heights.

7. Hair and fingernails continue growing after death.
In order for fingernails and hair to grow after someone is dead, the person would need to still be eating and digesting nutrients and performing cellular processes. Of course, that would interfere with the whole “being dead” thing. So there’s no way the body is producing more keratin in order to make hair and fingernails.
However, skin and hair can appear to grow post-mortem. As the dead skin begins to dry out, they retract and pull away from the hair shafts and nail beds. The hair and fingernails are not affected by the lack of moisture and do not shrink, which can make it seem as if they had grown. This also makes clean-shaven men appear to have grown stubble. Many funeral homes will apply moisturizer after the corpse has been washed in order to reduce the amount of drying prior to the memorial service.

8. Cracking your knuckles gives you arthritis.
While it makes sense on the surface that repeatedly pushing and stretching joints to make them crack would eventually lead to osteoarthritis, which is the painful deterioration of the joints, studies that have been performed on the topic have not been able to show a connection. In 1998, Donald Unger published a paper that revealed he had been cracking the knuckles in his left hand every day for 60 years, but not at all on his right hand. There was no difference in the joint health between the two hands, and Unger received the 2009 Ig Nobel Prize in Medicine for his work.
Synovial fluid is a substance that acts as a cushion and reduce friction in synovial joints, such as knuckles, elbows, knees, and hips. When the joints are stretched and the joint capsule separates, the decreased pressure within the capsule releases gas, forming a bubble to make up for the dead space. Pressing on the joint can create a loud, audible pop as the bubble breaks and the joint capsule returns to its normal size. If cracking knuckles is associated with pain, it may indicate damaged joints that need to be addressed. The cracking sound can also come from tendons, which can reduce their strength over time.

9. It takes seven years to digest swallowed chewing gum.
Chewing gum does not take seven years to digest. In fact, you don’t even digest it at all. Aside from a small amount of sweeteners and flavorings, there’s really not a lot inside the gum that the human body can actually break down and use. The bulk of gum is made out of rubbery polymers known as elastomers along with glycerin and vegetable oil-based ingredients to keep the gum soft and moist. Once the body has extracted what little it can from the gum, the rest is passed along as waste, just like anything else. 
However, that doesn’t mean swallowing gum is a great idea. Swallowing large amounts of gum can cause constipation and gastrointestinal blockage that needs to be removed by a physician. Gum can also fuse with other non-digestible items in the digestive tract such as coins, small toys, and sharp sunflower seed shells, which could contribute to gastrointestinal blockage or injury. While gum won’t stick around in your gut for seven years, it’s probably still safer to spit it out in a garbage can and wait to give it to children until they are old enough to know not to swallow it.

10. Antibiotics kill viruses. 
This one pops up every cold and flu season. Antibiotics, by their very definition, kill bacteria. The common cold and influenza are viruses and are not affected by antibiotic use. While some might think that taking antibiotics could be helpful on some level and want them for viral disease, that is dead wrong and could actually bring on more problems. Taking antibiotics in a manner contrary to their intended purpose or dosage instruction could cause other common bacteria within the body to become drug-resistant, which has become critically important. This could create “superbugs” that cause illness much worse than the primary 
The CDC has reported that physicians write tens of millions of antibiotic prescriptions each year for illnesses that are viral. This is partly due to uncertainty of the cause and badgering from the patients (or the parents of children). Some doctors are slightly more justified in prescribing antibiotics for a condition that can be bacterial or viral without making the patient wait days for lab results to return determining the cause. However, it is important for patients to understand why antibiotics don’t kill virus and to not demand drugs that will likely do more harm than good.

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article taken from Business Insider (original link)

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