The Wise Book of Whys (8 page)

Why a Gecko’s Feet Can Stick to Almost Anything

It
has been observed since the fourth century BC that geckos have the ability to climb walls, hang upside down, and apparently “stick” to anything. Aristotle was the first person known to have commented on the phenomenon, stating geckos have the ability to “run up and down a tree in any way, even with the head downwards.” It wasn’t until recently that it was discovered what gave them this Spider-Man-like ability.

Gecko
s have millions of tiny hairs on their toes called seta (“setae” being Latin for “bristle”). All combined, these hair-like tissues give a washboard type appearance to a gecko’s toes. Each one of these seta has thousands of thinner hair-like structures that have flat caps at the ends called spatulae (yes the same meaning as the thing that flips our pancakes). These spatulae use what is called van der Waals’ force to allow the gecko’s feet to adhere to objects.

More specifically, all of these seta and spatulae combined give the gecko’s feet an extremely large surface area, compared to its size. This surface area allows the gecko to take advantage of attraction caused by van der Waals
’ force. Van der Waals’ force, simply stated, is the combined attractive forces between molecules. Normally, the force between molecules is too minute to matter; however, given the light weight nature of a gecko (approximately 2.5 ounces) and the extreme number of spatulae, the combined force allows the gecko to “stick” to almost anything. This surface area is so great that it has been shown that if a mature gecko were to have all of their seta in contact with a surface at one time, it could potentially support up to 290 lbs.

There may be even more going on here as well, though it’s still up for debate. A study published in the
Journal of the Royal Society Interface
in the summer of 2011 showed that geckos leave footprints in the form of phospholipid residue. Phospholipids are a type of lipid (molecule that forms fats and waxes) that can form with two layers. These layers allow it to both attract water on one side and repel it on the other. This study suggests that there might be more going on with a gecko’s ability than we currently realize, and it is thought by its publishers that these phospholipids might also play a role in a gecko’s sticky talent.

While the discovery of phospholipids in the gecko’s footprint brings a new factor to the equation, the ancillary evidence that a gecko cannot “stick” to Teflon is a strong indication that van der Waals
’ force is the main mediator in their abilities. Teflon (Polytetrafluoroethylene) is mainly carbon and fluorine. Fluorine itself is highly electronegative, meaning it really really likes to attract electrons to itself. Because of this, it tends to mitigate what is known as the “London dispersion force.” This force is thought to usually be the dominate player in the van der Waals’ force. A gecko, which is dependent on the sum total of all of the factors of van der Waals’ force, would find it extremely difficult to stick to anything that eliminates its ability to utilize the force. And indeed, geckos cannot “stick” to Teflon.

Why
America is Called America

Amerigo Vespucci was a navigator that traveled to “the new world” in 1499 and 1502. Being a well-educated man, he realized that this new world was not part of Asia, as some had initially thought. Vespucci chose to write about his travels, and his books were published in 1502 and 1504. Being both entertaining and educational, his accounts of the new world were reprinted in almost every European language.

In 1507, a German cartographer, Martin Waldseemüller, chose to make a new map that included the new world. He and two scholarly partners were
aware of Vespucci’s writings but were ignorant of Columbus’s expeditions. As such, they mistakenly thought Vespucci discovered this new land and so named it after him, stating:

“But now these parts (Europe, Asia and Africa, the three continents of the Ptolemaic geography) have been extensively explored and a fourth part has been discovered by Americus Vespuccius (the Latin form of Vespucci’s name), I do not see what right any one would have to object to calling this part after Americus, who discovered it and who is a man of intelligence, and so to name it Amerige, that is, the Land of Americus, or America: since both Europa and Asia got their names from women.”

When the new map, approximately 8 feet by 4 feet, was unveiled by Waldseemüller, it had the large title “AMERICA” across what is now present-day Brazil. Waldseemüller used Vespucci’s travelogues as a reference for his drawing, so his map had South America as the only part of this new western hemisphere. When North America was later added, the mapmakers of the time retained the original name. In 1538, the famous geographer Gerard Mercator chose to name the entire north and south parts of America as one large “America” for the entire western hemisphere.

Christopher Columbus might well have ha
d the new world named after him had it not been for two shortcomings. The first was that Columbus was under the mistaken impression that he had found a new route to Asia and was not aware that America was an entirely new continent. The second was that at this time the masses were not widely aware of his travels. Had they been, Mr. Waldseemüller and his colleagues might have named it Columba! Of course, had the Norsemen’s previous journeys to the “New World” (and possibly Muslim and Chinese explorers before) been widely known, another name might have been chosen altogether.  As it happened, Vespucci did write about it and was the first to call this land the “Novus Mundus” (Latin for “New World”).

Why Garlic Makes Breath Smell Bad

There are a few things going on to cause this bad smell, but principally the root cause is various sulfuric compounds from the garlic. Initially, most of the bad breath resulting from eating garlic comes directly from the sulfuric compounds introduced into your mouth
. Garlic also promotes the growth of some of the microbes in your mouth that already cause bad breath, which further exacerbates the problem.

You may have noticed that even if you brush your teeth, rinse with mouthwash, and other such methods to clean out these compounds and various microbes from your mouth, the bad breath caused by garlic still remains to some extent
. This has to do with the fact that some of these sulfuric compounds get metabolized, eventually making their way into your blood stream.

The primary smelly culprit here has been found to be allyl methyl sulfide, which is passed into the blood during the digestive process
. Once it’s in your blood, it eventually gets passed out of your body through various bodily excretions, which includes being exuded through your pores and also passed into the air that fills your lungs. So as you breathe, the air goes into your lungs and is contaminated by the allyl methyl sulfide; this in turn causes your breath to continue to smell even if you’ve cleaned your mouth out.

As mentioned, this sulfuric compound will not only find its way into the air in your lungs, but also will be exude
d from your pores. This causes your whole body to smell, not just your breath. As you are excreting this sulfide, you essentially are wearing a stinky perfume. This effect lasts as long as it takes for your body to get rid of the stinky sulfuric compounds, which can be anywhere from a few hours to as much as a day after eating the garlic.

Why Poop is Brown

Poop is brown due to bile from your gall bladder being metabolized by the bacteria in your intestines. This results in a by-product called stercobilin, which, in turn, makes poop look brown-ish.

Without this stercobilin, your poop would typically look grey-ish/white
. Because of this, a sure sign you are having problems with bile production, such as a blocked bile duct by a gall stone or something more serious like pancreatic cancer, is if you notice your poop is this white/grey-ish color.

In the end, brown poop is a pretty good sign you are a relatively healthy individual
. Some other common poop colors that generally aren’t a good sign of health are as follows:

If you notice your poop is red, this could be a sign of internal bleeding or could just mean you’ve recently eaten beets
. If the cause is bleeding and the bleeding is from your stomach or throat, however, your poop won’t be red, but rather black and will smell worse than that time you decided you should eat a box of Twinkies and a box of Cheesy Handi-Snacks all in one sitting.

Yellow poop means there is a lot of fat in your feces
. This is not a good sign. Consider turning this into a positive by making poop candles with your fatty deposits. Yellow poop also has a very strong odor, which will give your poo-candles that little something extra.

Green poop is an indicator of some sort of bacterial infection or that you have recently eaten a lot of leafy foods.

Why There is Braille on Drive Up ATMs

Mainly, it is because it is required by law, thanks to the ADA Accessibility Guidelines for Buildings and Facilities
. There are certain exceptions to these requirements when it comes to drive-up ATMs vs. walk-up ATMs, such as the differing requirements on the “Reach Ranges” in section 4.34.3. However, getting rid of the Braille is not one of these exceptions, despite initial protests from the American Banker’s Association who argued that any visually impaired person could simply get the driver to help. The committee in charge of developing these standards rejected this argument because it would no longer allow a visually impaired person to use the ATM independently.

You’ll also often hear people say th
at the reason behind including Braille on drive-up ATMs has to do with being “cheaper to make one ATM machine, rather than two different models” or in a similar vein “cheaper to have one set of buttons with Braille, than one with and one without.” This may or may not be true, but given that the American Bankers Association fought to try to remove requirements to make the drive-up ATMs accessible to the visually impaired, it would seem this “cheaper” factor, if it exists, wasn’t a contributing factor in the switch, presumably because when factoring in the cost of replacing the older non-Braille ATMs, the cost of “one design / set of buttons” wasn’t enough of a benefit for the ABA.

In the end, bli
nd people actually do use drive-up ATMs all the time, contrary to what many people think. It’s not uncommon at all for them to run errands in a taxi-cab, for instance. When they do, a drive-up ATM is certainly more convenient for a blind person, given someone can drive them right up to the ATM. And they probably wouldn’t want to trust the cab driver with their card and pin number.

Up until somewhat recently, a related questio
n would have been, “why do walk-up ATMs have Braille when many ATMs don’t have any facility for letting the blind person know what is happening on the screen?”  This situation has since been improved, but for a long time, there was no set way to make the interaction with the ATM, beyond the Braille, accessible to the visually impaired. Initially, no one was really sure what the best way to handle this aspect of accessibility would be, so the Accessibility Guidelines didn’t address it.

Thus, in the early days, quite a lot of banks simply provide
d a Braille instruction manual for a given ATM and the visually impaired user would need to follow the steps exactly to do a certain task and hope nothing went wrong or that the ATM didn’t suddenly get a software update that changed that interaction. These instructions can still be found on many ATMs, but today there is also, generally, some sort of audible system to let the visually impaired user know what’s happening  on the screen (usually through a headphone jack, for privacy).