- [Narrator] From the same
expiry date on all crisps to why snorkels aren't as
long as you'd like them to be, here are ten more hidden
secrets in everyday things. - Amazing! (peaceful music) - [Narrator] Number ten:
Sign on the Line or Not. When signing a check, you may think you're signing
on the signature line, but if you get a magnifying
glass and look very closely at that line, it is actually
made up of repeating print which says AUTHORIZEDSIGNATURE
over and over. The print is so small, it appears to be a regular
straight line at first glance, but if you look carefully you
should be able to make it out. This is done as a security feature, technically called microprinting, where the print is so
small that if photocopied, it becomes an actual blurry line. So if you want to check
if your check is real, squint at the line where you sign. Number nine: Blank Pages. If you're an avid reader of paper books, you may have noticed there are often blank pages at the end of the book. Why are they there? No, it's not so you can
freeform your thoughts before typing out your actual
Amazon review of the novel. Books are made up of digitally printed and folded sheets of
paper called signatures. They're all bound together,
attached to a cover, and that makes up your book. Digitally printed
signatures can be anywhere from two to 48 pages,
depending on the press. Sometimes, the text ends before the last page of the last signature. This is how large publishers print books, but print on demand services for self-published authors may be different, printing several pages on
one large piece of paper which is later cut. In this case, you may have fewer pages than would fit on the large printing sheet and you get some blank pages. Number eight: Tram/Train
Criss-Crossing Overhead Line. While riding the tram,
you may look up and notice its criss-crossing overhead lines. Are they designed that way to
remind you of a 90s rap song? No, there's a functional reason for the criss-cross
pattern called the sweep. Trams and some trains run on
a pantograph catenary system where the electricity is transferred from the catenary wire to the locomotive. The sliding strip creates
the electrical contact to the catenary wire, while
the pantograph spring system maintains permanent contact at any speed. The wear and tear from the sliding strip touching the copper wires can
cause erosion on the pylons. The actual reason for
the criss-crossing lines is to spread the erosion and wear evenly along the contact strips,
preventing grooves from developing so they can last longer. Number seven: Snorkels. You may know that snorkels
allow people to breathe while swimming underwater. Unlike scuba equipment,
which requires an air tank, snorkels stick up out of water allowing the wearer to breathe
air from the atmosphere. Most snorkels are about
30 centimeters long, and none are longer than 40 centimeters. Naturally, this limits a person to stay close to the surface. Wouldn't a longer design
be more convenient? No, actually it wouldn't, and this is why they aren't that long. In deeper water, the surrounding
water pressure is higher. Your lungs would be unable to inflate when the snorkeler inhales because the muscles that expand the
lungs are not strong enough to operate against the higher pressure. This problematic pressure difference across the tissues in the lungs between the blood
capillaries and airspaces would increase the risk
of pulmonary edema. Using a snorkel also causes wearers to re-inhale some carbon dioxide, and a smaller tube reduces the problem. The reason scuba divers
can breathe, though, is because they carry their
own source of breathing gas, usually compressed air, and don't rely on breathing air under
pressure from the surface. So stick with your 30 centimeter snorkel. The idea for a longer one is all wet. Number six: In N Out
Burgers' Bible Verses. Many people enjoy In N Out Burgers, and some have noticed their
burger wrappers, fry containers, and cups contain tiny
notations in strange places, like the underside of cups or near the seam of the
burger or fry pouch. They're easy to overlook, but some sharp-eyed
consumers have noticed them. If you look closely and
have studied a Bible, you may realize these notations
refer to Bible passages. For example, John 3:16 or Proverbs 3:5. Some believe a conspiracy is afoot, that In N Out represents a sect or cult, or that they hold secret
Bible study classes at their location, but most
people don't even notice these notations and
the actual Bible verses don't appear on the wrappers so as far as conspiracies
go it doesn't hold water. Fortunately, your cup does. In reality, the practice
began in the '80s, and simply represents
the Christian beliefs of the Snyder family, who started In N Out and still own most of the company. Number five: Incandescent Light Bulbs. Light bulbs light up our lives, but have you ever wondered
about their shape? Often hidden under a lampshade, they could be shaped like anything, but the bulb has a round shape
that tapers down to the base. This was chosen when light
bulbs were first developed because it was easily
made by glass blowers. The spherical design is also ideal for controlling heat and light emissions. Lately, these have been
replaced by the newer, more efficient spiral-shaped bulbs, but sometimes even that design is hidden inside a spherical bulb. A bright idea in design. Number four: Toothpaste Stripes. This one might come as a surprise. Multi-colored stripes on
toothpaste were first introduced to the oral hygiene market
by Aquafresh in 1973 when it entered the toothpaste market. Although insanely simple, this product development
was pretty ingenious. Back then, there was a growing
awareness and interest in having a toothpaste that
not only prevents decay, but also promotes fresh breath. In order to capitalize on this, toothpaste brands like Aquafresh divided their toothpaste
up with different colors to represent the benefits of its product. It originally had two colors
for double protection, by combining a white fluoride toothpaste for cavity and decay protection and a blue Aquagel for fresh breath. Later, a third red gel was added for healthy gums and plaque prevention. As such, they now exist
as a way to illustrate the product's core benefits. You may be thinking it's rather obvious, but here's the secret of this one. Most non-striped toothpaste offered the exact same hygienic benefits. Striped toothpaste isn't
necessarily special. In fact the only thing
that's special is us, because we think we think
we're getting a lot more than other standard white brands. In reality, all's that
happened is that companies have differentiated their products to match our strange
preferences because research has just shown that most buyers now prefer the stripey variety over
the plain old white product. Number three: McFlurry
Spoon Hollow Bottom. If you enjoy McDonald's McFlurrys, you may have thought
the hole at the end of the McFlurry spoon was
meant to be used as a straw. Makes sense, right? As the McFlurry melts, you can easily enjoy it as a milkshake, but that's not the reason
for the hole in the spoon. When the McDonald's worker
makes your McFlurry, they put ice cream in the cup, add the candy or cookies, then place it in a machine
that automatically stirs it with the spoon that comes with it. The hole on the end allows
the spoon to attach to the machine so your McFlurry can go through an appropriate blizzard of
stirring before you consume it. Number two: Walkers Crisps. Most consumers are so eager
to tear the bag of Walkers Crisps open, they don't pay
much attention to the date, but some discerning people
have noticed that the bags always go out of date on a Saturday, a little inconvenient if
you consistently pay out on Walker's chips only on Sundays. So, does the flavor take a holiday on Saturday night or what? It turns out the reason is
because of Walker's production schedule, which starts on a Sunday, so all bags will have an
expiration date on Saturday. However, many of us know
chips usually taste okay for a few days after that date, so don't be too worried about that date. Number one: Who Killed the King of Hearts? If you've ever been
bored during a card game, you might have pondered at
the design of the cards. Some people have noticed
the King of hearts actually has a sword stuck in his head, or at least that's how
it appears on the card. If you look at the top of the card, you might think he's
stabbing himself in the head, and that may be consistent
with the fact that the card is thought to be based on Francis King Charlemagne, who
is rumored to have gone insane and put a sword through his head, hence the term suicide king. However, looking further down we can see both his hands are accounted for, so the hand holding the sword
belongs to someone else. Is this a case of lovers' quarrel with the Queen of hearts maybe? Actually, some people believe
it's the Queen of spades, but if you look carefully at her sleeve the pattern is similar
but not exactly the same. The Jack of hearts is another suspect, although his sleeves aren't shown, but his clothes have a similar pattern. In truth, the sword actually appears to be going into the king's head due to poor card copying over the years. The earliest forms of the
card featured an ax head, which disappeared after
several generations of inexact copying. If you were interested about the fact about the King of hearts, then you should watch this video. It has another hidden secret on the card you might not have noticed.
