Les gardes royaux doivent suivre un protocole en cas d'évanouissement + D'autres faits uniques
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FunTranscript
00:00:00Can you hear a sound and perceive almost instantly a specific color?
00:00:06You could be part of a particular group of people, about 4% of the world's population,
00:00:12capable of experiencing synesthesia.
00:00:15It's not you who imagine things.
00:00:17A new study tries to show that synesthesia is very real,
00:00:21and brain scanners prove it.
00:00:23When these synesthetic people hear colors,
00:00:26the scanners reveal that the parts of their brain linked to sight and sound communicate with each other.
00:00:32Since synesthesia seems to be of a genetic nature,
00:00:36some researchers have chosen three families where this characteristic was present.
00:00:41They then played with DNA sequencing
00:00:44and compared the genes of synesthetic members of the same family to those that were deprived of it.
00:00:49They still haven't completely confirmed this unique characteristic,
00:00:53but they managed to restrict it to as few as 37 possible genes.
00:00:58Sometimes, after a nap in an uncomfortable position,
00:01:01you may have felt tingling or a tingling in your arm or leg.
00:01:06You might think it has everything to do with poor blood circulation.
00:01:10But in fact, it could be due to a little thing called paresthesia.
00:01:15It's when your body starts to feel unusual sensations
00:01:19because your nerves are compressed or irritated.
00:01:22Paresthesia can give you anything,
00:01:25from a burning sensation to this annoying sensation that your arm or leg no longer responds to at all.
00:01:30It could even add discomfort or these good old characteristic tingling.
00:01:35Normally, it shouldn't take you more than 30 minutes.
00:01:39Shake the affected part of the body vigorously, and it could speed up the process.
00:01:44If it lasts longer, or if you have repeated episodes of paresthesia for no apparent reason,
00:01:50it is preferable to consult a specialist to make sure everything is fine.
00:01:55Do you know what is also worth checking?
00:01:58If you have already given a blue thumb to this video,
00:02:01and if you are subscribed to the channel.
00:02:03You know, just to be sure not to miss anything.
00:02:07In normal times, you never think about your stomach or all the chemistry it contains.
00:02:13Can you imagine if one day this substance simply disappeared?
00:02:17It contains chlorhydric acid, which is also used in fertilizers, rubber and steel.
00:02:24If you inhale it, you will have serious breathing problems and in your nose.
00:02:29Every time you chew something, your stomach begins to produce these gastric juices.
00:02:34They are useful because they can break down proteins, activate pepsin,
00:02:38eliminate all the bacteria that you have been able to swallow without even knowing it,
00:02:42and tell your food to go, well, out.
00:02:48Without this acid, the food would stay right there,
00:02:51turning into a breeding ground for bacteria.
00:02:55Proteins and nutrients would not be absorbed by it.
00:02:58Your lunch could quickly go through your digestive system,
00:03:03and you would end up expelling undigested food.
00:03:08There is a reason why paper cuttings hurt so much.
00:03:12To begin with, they occur on the tip of your fingers, which are very sensitive areas.
00:03:18It is because they are full of receptors, which are like the receptionists of your body,
00:03:22helping you determine the size, shape, texture and temperature of the things you touch.
00:03:29When you cut yourself with paper, these receptors are instantly solicited,
00:03:34sending unpleasant information to the brain.
00:03:37Paper cuttings do not look like a sharp cut made with a sharp knife either,
00:03:42because of the foam on the edges of the sheet.
00:03:45This exposes your receptors even more.
00:03:48Paper cuttings do not bleed much and do not coagulate well either,
00:03:52which leaves the nerves alive and aggravates the discomfort even more.
00:03:57We always use our hands, so these cuts continue to reopen,
00:04:01taking an infinite amount of time to heal.
00:04:04Paper is often treated with chemicals that can irritate your skin.
00:04:10The déjà vu seems to strike from nowhere.
00:04:13You are not a wizard, and you do not communicate with the spirits of the beyond either.
00:04:18It is simply your brain that works badly.
00:04:22According to doctors, the déjà vu occurs when two parts of the brain have a little trouble understanding each other.
00:04:28These two parts are located on each side of your skull, just above your temples.
00:04:33They are a bit like the memory cards of your brain,
00:04:36and help you remember certain things, such as places or the face of other people.
00:04:42They even disconnect emotions and are in charge of language.
00:04:46Now, in each of these areas of the brain, which are called temporal lobes,
00:04:51there is a region called the hippocampus.
00:04:53It is responsible for short-term memory.
00:04:56Sometimes, the brain can encounter small malfunctions, confusing the hippocampus.
00:05:01It is then that we feel the déjà vu.
00:05:04This whole process disturbs your memory of recognition,
00:05:08giving you this strange feeling that you have already been there before,
00:05:12or that you have already met a person you see for the very first time.
00:05:17It is a completely normal process,
00:05:19and you are more likely to experience déjà vu if you are between 15 and 25 years old.
00:05:25It also seems that people who travel a lot,
00:05:28or have the ability to remember their dreams, experience it more often.
00:05:34It is difficult to imagine that an entire civilization can survive without anyone being able to see.
00:05:41This seems highly improbable, and here is why.
00:05:45First, imagine trying to cultivate crops without even being able to see what you are doing.
00:05:51The preparation of the soil would become a nightmare,
00:05:54because, without sight, we would get lost in the first field of wheat,
00:05:58without any reference point.
00:06:00Harvesting just a little of this food would not be an easy thing either.
00:06:04Animals could be hiding everywhere, ready to harm us.
00:06:08Communication would be as complicated,
00:06:11because we would not be able to read something without touching it.
00:06:15Even our social lives would be different.
00:06:18Without sight, we should trust our voices.
00:06:21Trusting someone without knowing who else is listening,
00:06:24thank you.
00:06:26If you have ever eaten a very spicy pepper,
00:06:29you know that it is not technically hot.
00:06:31In terms of temperature,
00:06:33then why do we feel like it is burning us,
00:06:36even if it has just come out of the refrigerator?
00:06:39Well, spicy foods contain chemical compounds
00:06:43that deceive our body so that it alters its internal thermostat.
00:06:47First, our lips and tongue feel like they are on fire.
00:06:51Then, our nose starts to run,
00:06:54and we can even shed a tear, or two.
00:06:57The blood vessels dilate,
00:06:59and suddenly, our body temperature increases.
00:07:02To cool things down, we start to sweat.
00:07:06Our lungs can also participate
00:07:08and signal to our diaphragm to produce hocks,
00:07:11in order to chase this irritating intruder.
00:07:15In most cases,
00:07:17all these bodily triggers are caused by a substance called capsaicin,
00:07:21often found in strong peppers like habanero and cayenne pepper.
00:07:26Even if we sometimes feel like moving while we are dreaming,
00:07:30this is not the case thanks to a complex system in our body.
00:07:34This one prevents our muscles from doing all kinds of extravagant things
00:07:38related to crazy stories that our brain could invent during the night.
00:07:42It turns out that most of this brain chemistry
00:07:45occurs during the paradoxal sleep phase, or REM,
00:07:48about 90 minutes after you fall asleep.
00:07:52During this phase,
00:07:54your brain experiences some of the strangest dreams,
00:07:57while your voluntary muscles,
00:07:59like your arms and legs, are deactivated.
00:08:02This muscular blockage is the reason why some people wake up
00:08:06and cannot move,
00:08:08experiencing what is called sleep paralysis.
00:08:11The big mystery was to know how the muscles got into this state of paralysis.
00:08:16At first, researchers thought that glycine, a neurotransmitter,
00:08:20was responsible for it.
00:08:22Research has shown that even if we block the production of glycine,
00:08:26the muscles remain frozen.
00:08:29It took a little more time for scientists to discover
00:08:32that in order to maintain these immobile muscles,
00:08:35you need both glycine
00:08:37and another chemical substance of communication,
00:08:40called GABA.
00:08:42We are not as hairy as our ancestors,
00:08:45but we still have the skin of a hen when we are cold.
00:08:48It is because of these little muscles in our hair follicles,
00:08:51called hair erector muscles,
00:08:54that pull them up.
00:08:56For furry animals,
00:08:58this feature helps them stay warm,
00:09:00but for us, it does not accomplish much in terms of heat.
00:09:04However, we and a few other less hairy creatures
00:09:07have maintained this ability over the years.
00:09:10Experiments have been carried out to find out more about this hen's skin.
00:09:14We found three key actors,
00:09:16these hair erector muscles,
00:09:18sympathetic nerves and hair follicles.
00:09:21When we tried to influence the nerves,
00:09:23the growth of the hair slowed down.
00:09:26These nerves and our hair follicles work together,
00:09:29creating chemical synapses.
00:09:32Thus, hen's skin is not only a quick solution
00:09:35to overcome a low temperature.
00:09:38It could also communicate to our stem cells
00:09:41to grow more hair in the long run.
00:09:44This is why the loss of these muscle cells
00:09:46could be linked to baldness.
00:09:50I have drawn up a list of the most frightening abandoned sites in the world.
00:09:54There is everything,
00:09:55ghost skyscrapers in the old amusement park.
00:09:58Shall we go for a ride?
00:10:00If you have seen Martin Scorsese's Shooter Island,
00:10:03you know that some islands can be extremely sinister.
00:10:06Even if this abandoned place looks like the setting of a horror movie,
00:10:09it is a little more real.
00:10:12The island of Hashima is located 15 km from the city of Nagasaki.
00:10:16It has been abandoned for nearly 50 years.
00:10:19You see, when we leave unoccupied buildings
00:10:21and without surveillance in deserted areas for a while,
00:10:24nature usually takes over.
00:10:27Judging by its current appearance,
00:10:29I would never have guessed that the island of Hashima
00:10:31was once an important coal extraction zone.
00:10:35All the coal extracted from the region
00:10:37was shipped to the rest of the country
00:10:39to feed its rapid industrialization.
00:10:42But mineral resources are limited, we know.
00:10:45Thus, when coal reserves began to decrease,
00:10:49people had little more to do in the region.
00:10:53Which brings us back to today.
00:10:55If you feel adventurous,
00:10:57you can take a boat tour of Nagasaki on the island of Hashima
00:11:00and discover this dystopian science fiction city.
00:11:03You will see empty buildings,
00:11:05invaded by vegetation,
00:11:07and you will be kept away from buildings that could collapse.
00:11:10An excellent idea for a Sunday, isn't it?
00:11:14This is what I call
00:11:16Disney,
00:11:17but with a dark touch.
00:11:19In 2014, a group of promoters said
00:11:22that it would be a good idea to build
00:11:24a luxurious castle city like Disney
00:11:26in the middle of a Turkish forest.
00:11:29They aimed at the rich Europeans,
00:11:31with sums ranging from 370 to 500,000 euros,
00:11:35to invest in their crazy business.
00:11:40As the city was built near a city known for its hot springs,
00:11:44the owners of these luxurious villas
00:11:46would even have their own jacuzzi.
00:11:50The problem is that people didn't like the idea.
00:11:53Some began to complain that the architecture
00:11:55was too far from the Ottoman style of the region,
00:11:58and others thought that too many trees had been cut
00:12:00to build this fairy tale city.
00:12:02In the end,
00:12:03the promoters have accumulated so many fines
00:12:05that they had to declare bankruptcy
00:12:07and the project was abandoned.
00:12:09They didn't demolish the castles, though.
00:12:11So now it all looks like a Disney movie,
00:12:14a little sinister.
00:12:18The skyscrapers are fine,
00:12:20but have you ever seen the world's biggest ghost skyscraper?
00:12:23The Golden Finance 117
00:12:25was supposed to be the masterpiece
00:12:27of the Golden Metropolitan Scheme,
00:12:29a tentacular artificial city
00:12:31belonging to the billionaire Pan Sutong.
00:12:34This mini-city was to be a residential and commercial center
00:12:37just a few minutes from the city center of Tianjin.
00:12:42It was to be made up of French and Italian-style manors,
00:12:46a polo club,
00:12:47and even a wine museum.
00:12:49The promoters had the intention of attracting the super-rich.
00:12:52The 128-story building
00:12:54was considered the jewel of the mini-city.
00:12:57And I mean literally,
00:12:59the top of the building was supposed to be the shape of a diamond.
00:13:02Construction began in 2008,
00:13:05and it's still not finished.
00:13:07The overall project was estimated at 10 billion US dollars.
00:13:11But due to several unfortunate events,
00:13:14it has never been fully realized.
00:13:16Some say that all this was probably doomed to failure from the start.
00:13:20Because people who could afford to live in such a place
00:13:23did not want to live in a second-rate industrial city.
00:13:27And as you may remember,
00:13:29there was a great economic recession in 2008.
00:13:32It really slowed things down.
00:13:35Despite everything, this ghost skyscraper
00:13:37was the fifth tallest building in the world at the time.
00:13:41If you had to choose three synonymous words of utopia,
00:13:44which would you choose?
00:13:45I would say, for example, happiness, peace and abundance.
00:13:48This city, supposed to be utopian,
00:13:50could not be further from these qualities.
00:13:53Welcome to the Mojave Desert,
00:13:55in California.
00:13:57Do you see the city square on the sandy ground?
00:14:00These lines are the remains of a project
00:14:02that never reached its final stage.
00:14:05This city was supposed to be called California City.
00:14:09This utopian city was imagined by Nat Mendelsohn,
00:14:13a university professor who studied urbanism a lot.
00:14:16The project began in the late 1950s
00:14:19when he bought more than 32,000 hectares of land in the desert.
00:14:23He wanted to create a place where families would flourish.
00:14:26At the time, housing was affordable,
00:14:28and the city was equipped with leisure options
00:14:30such as a golf course, a pool and playgrounds.
00:14:34People started buying land,
00:14:37but the project was interrupted.
00:14:40So, if you get out of Los Angeles by car,
00:14:43you may see a small hill of houses,
00:14:45a tiny part of what California City was supposed to become.
00:14:50According to you, which European country is full of abandoned places?
00:14:54If you answered Spain, then bravo!
00:14:57Here are a few.
00:14:59What was once planned to be a center of luxury villas
00:15:02is now a graffiti havoc.
00:15:05The place began to be built in 1969,
00:15:08but only a year later, the work was abandoned.
00:15:11You can also find the Festival Club in Ibiza.
00:15:14You see, Ibiza has not always been a party place.
00:15:17This club opened its doors in 1972,
00:15:20but two years later, Spain experienced a major oil crisis,
00:15:24and fewer and fewer tourists went to visit the island.
00:15:27The club ended up being abandoned,
00:15:29and today, we mainly come here to admire the graffiti.
00:15:33The exterior of the houses is in perfect condition.
00:15:36It is difficult to believe that they are actually abandoned.
00:15:39According to the explorer who found them,
00:15:41they would have been delivered to this sad fate in 2008.
00:15:45Once again, this terrible year of economic recession.
00:15:48The company that built them went bankrupt
00:15:51during the last quarter of the construction,
00:15:53and had to abandon the project at its very last stage.
00:15:56What a sad end.
00:15:59In Miami Beach, you will find a luxurious abandoned hotel
00:16:02that once hosted a Beatles concert.
00:16:05At the end of the 1950s,
00:16:07it was the favorite place of celebrities like Frank Sinatra.
00:16:11Today, the Oville complex has been demolished.
00:16:14It was closed in 2007,
00:16:16after a fire damaged certain structures of the building.
00:16:20For a while, they decided to leave the hotel as it was,
00:16:24with its furniture and memories still inside.
00:16:27Let's see what it looked like.
00:16:30The main entrance and the hall
00:16:32It was a beautiful 50s style ambiance.
00:16:35The kitchen was still equipped with dishes and cutlery,
00:16:38the bathroom had cabins and hair dryers,
00:16:41and electronic keys, I dig the floor, everywhere.
00:16:45It was in the big ballroom of the hotel that magic operated.
00:16:48In 1964, the Beatles gave a concert there
00:16:51during which thousands of fans without tickets
00:16:53waited outside, hoping to see the stars.
00:16:57The Oville may have played an important role
00:16:59in American cultural history.
00:17:01But today, it's just an abandoned site.
00:17:06There is no doubt that some of the most interesting abandoned places in the world
00:17:10are old amusement parks.
00:17:13Amusement parks are usually full of laughter and happy moments.
00:17:17But not those.
00:17:19The Nara Dreamland was supposed to be the Disney World of Japan,
00:17:22but the project failed.
00:17:25Today, it's just a dream.
00:17:28If you had visited it before its demolition,
00:17:31this is what you would have seen.
00:17:33Your heart was beating faster than usual
00:17:35when you passed in front of these Russian mountains covered with fog.
00:17:38Was it supposed to be the Servin?
00:17:40And yes.
00:17:41Everyone in this place was shouting,
00:17:43get out of here!
00:17:44But we are curious.
00:17:46The ground of the park,
00:17:48billiard balls and disfigured stuffed animals.
00:17:51Want to enter an empty restaurant?
00:17:53It's weird how the tables and stools were left in their place.
00:17:57In what used to be a souvenir shop,
00:17:59there were empty shelves and an old ticket dispenser.
00:18:03So, you too, all this troubled you.
00:18:05What a fright!
00:18:09The pilots are not allowed to take identical meals when they work.
00:18:12Imagine that you are on a trans-oceanic flight,
00:18:14the plane flies over the Pacific Ocean.
00:18:16The air hostesses distribute the meals of the evening.
00:18:19Everyone enjoys the pasta.
00:18:21But the sauce tastes a little weird.
00:18:24It's probably normal.
00:18:26After all, we eat a plane meal.
00:18:28It can't taste like a star restaurant, can it?
00:18:32Time passes.
00:18:34Oh no!
00:18:35You were right.
00:18:36There was indeed a problem with the food.
00:18:39But if all passengers have the same problem,
00:18:41so do the pilots.
00:18:43To prevent that they are both sick,
00:18:45the pilots are advised not to take the same meal at the same time.
00:18:49So, if one pilot feels bad,
00:18:51the other can take over.
00:18:54This is not an imperative rule
00:18:56announced by the official aviation agencies.
00:18:58But most airlines establish their own rules in this regard.
00:19:02It makes sense.
00:19:04The on-board agents have access to hidden equipment such as a defibrillator,
00:19:08additional oxygen, an extractor and an adhesive tape.
00:19:11But the most interesting equipment they have
00:19:13are undoubtedly the handcuffs.
00:19:15These objects are there to protect the passengers,
00:19:18others and sometimes themselves.
00:19:20In fact, the crew members have everything they need
00:19:23to neutralize a possible troublemaker.
00:19:25The aviator sunglasses look cool on the pilots in the movies.
00:19:29But in real life, they don't wear polarized glasses.
00:19:32First of all, they have an anti-blinding effect.
00:19:35This can cause some problems in the cockpit.
00:19:37A pilot must be able to read the instruments.
00:19:39But cockpit equipment, such as LCD screens,
00:19:41emit a polarized light.
00:19:43A pilot wearing these glasses
00:19:45will therefore not be able to read the screens
00:19:47with 100% efficiency.
00:19:50For safety reasons,
00:19:52pilots must not wear sunglasses.
00:19:54Let's imagine a dazzling reflection
00:19:56coming from the windshield of another plane.
00:19:58But the pilot missed the mark
00:20:00because of his tinted glasses. Ouch!
00:20:02Have you ever noticed a hole in the tail of a plane?
00:20:05Well, most commercial planes have one.
00:20:08The next time you get on a plane,
00:20:10look closer.
00:20:11The hole has a fanciful name,
00:20:13the auxiliary power group.
00:20:15From the outside, it looks like a hole.
00:20:17But it's actually a hidden turbine engine.
00:20:19Most of the time,
00:20:21the auxiliary power group stays off during the entire flight.
00:20:23It starts to work when the plane lands.
00:20:25It powers the cabin lights,
00:20:27the air conditioning,
00:20:28and all the cockpit electronics.
00:20:30But don't underestimate the auxiliary power group's performance.
00:20:32It can also provide the power
00:20:34needed to start the main engines.
00:20:37You just watched a nice video
00:20:39and you learned what the auxiliary power group means.
00:20:41A perfect way to start a conversation in the evening.
00:20:44Unfortunately, you're not in a good mood.
00:20:46You just want to take the plane, land,
00:20:48and start your holidays.
00:20:49But you're not lucky.
00:20:50There's only one door to board.
00:20:52And you're in a queue.
00:20:54Why do planes always have several doors?
00:20:57According to experts,
00:20:58the main problem is that the runway takes up a lot of space.
00:21:01When a plane is loaded from the front and from the back,
00:21:04it occupies two runways,
00:21:06which is not ideal for the operators.
00:21:09Recently renovated or built airports
00:21:11tend to have a double boarding
00:21:13compared to former terminals.
00:21:16Change of scenery.
00:21:17Let's jump in a cruise ship.
00:21:19There are hidden passages and secret doors in these ships.
00:21:23These are the secrets of the initiator.
00:21:25The ship's crew works most often in their reserved area.
00:21:29How can an employee go from one place to another
00:21:32without using the stairs and doors used by the passengers?
00:21:35Well, there is a network of corridors and stairs
00:21:38all around the ship used only by the crew.
00:21:41I'm serious when I talk about secret doors.
00:21:43They get confused with the walls.
00:21:45They pass unnoticed for those who don't know where the door is.
00:21:48Maybe you can accidentally fall on it.
00:21:51Here's a clue.
00:21:52Watch out for the walls near the customers' stairs.
00:21:54They are in the corner.
00:21:56These gigantic cruise ships
00:21:58are actually floating metal objects.
00:22:00This leads me to a funny anecdote about cruise cabins.
00:22:03The walls of the cruise ship cabin are magnetic.
00:22:05Let's imagine you're on a cruise for a month
00:22:07across several countries.
00:22:08You collect magnets on the theme of the destination
00:22:11and you decorate your cabin.
00:22:12True cruise enthusiasts know the magic of magnets.
00:22:16They put some magnetic hooks in their luggage.
00:22:19Use the magnetic hooks to add additional storage in your cabin.
00:22:24Hang clothes, accessories, postcards or hats.
00:22:27Whatever you want.
00:22:28Let's talk about ships again.
00:22:30Why do some ships and boats have small holes
00:22:32that let the water escape permanently
00:22:34to keep the hull dry?
00:22:36Water accumulates over time in the hull
00:22:39and the pump of the hull evacuates it automatically.
00:22:42Ships don't have headlights.
00:22:44The use of a headlight could prevent accidents, right?
00:22:47If it works for cars, why not for ships?
00:22:49Headlights are the source of light.
00:22:51But the light that comes out of them
00:22:53bounces on the light source at some point.
00:22:55With cars, for example,
00:22:57the headlights work because the area to be lit is narrow
00:23:00and you can easily intervene if you see an obstacle on the road.
00:23:03For boats, it's extremely complicated.
00:23:06The light source must be powerful enough
00:23:09to illuminate the area the captain wants to monitor.
00:23:11Big cargo ships, for example,
00:23:13need more than a kilometre to stop or make decisions.
00:23:16In addition, you have to imagine
00:23:18how intense the light of the ship must be
00:23:20to illuminate the entire area in front of it.
00:23:22Ships are spotted using different types of lights
00:23:25called navigation lights.
00:23:27They are small but practical.
00:23:30They are arranged in a standardized way
00:23:32so that boats can spot each other.
00:23:35What's fascinating is that they're not only used
00:23:37to spot each other in the dark.
00:23:38They also indicate the movements
00:23:40and directions of other ships.
00:23:42Here's an example.
00:23:44Imagine a boat equipped with two navigation lights.
00:23:46The front one is lower, near the deck of the ship.
00:23:49The other one, at the back, is higher.
00:23:51This means that the boat is going to the right.
00:23:53It can safely pass next to the others
00:23:55without bumping into them.
00:23:57Trains don't have seatbelts.
00:23:59It's a bit weird, isn't it?
00:24:02Every time there's a train-related accident,
00:24:04this question comes up.
00:24:06Almost everywhere in the world,
00:24:08there are no seatbelts in trains.
00:24:10Several studies have been carried out on this subject.
00:24:12Some of them have created accident simulations.
00:24:14And the results were surprising.
00:24:16The use of seatbelts in a train
00:24:18could potentially increase the number of injuries.
00:24:21In cars, seatbelts are very effective
00:24:23in protecting the passenger
00:24:25and are systematically used.
00:24:27The logic behind the seatbelt
00:24:29is to protect the person
00:24:31when a collision causes a rapid deceleration.
00:24:33But trains have such momentum
00:24:36In a plane, passengers use seatbelts
00:24:38when taking off, landing
00:24:40and in case of turbulence.
00:24:42This is not the case for trains.
00:24:44Entering and leaving a station
00:24:46does not pose a high risk.
00:24:48Experts believe that the driver's concentration
00:24:50and regular maintenance
00:24:52are the best ways to strengthen railway safety.
00:24:54Now, you're travelling by train.
00:24:56You look out the window.
00:24:58There are small stones along the railway
00:25:00to accompany you on your journey.
00:25:02These stones are officially called
00:25:05They play a very important role.
00:25:07They support and maintain the railway.
00:25:09But they are not there by mere coincidence.
00:25:11Now, look at the stones up close.
00:25:13You can see that there is not one
00:25:15well carved on the tracks.
00:25:17These are not ordinary stones
00:25:19arranged randomly on the tracks.
00:25:21Each rock has sharp and abrupt edges.
00:25:23These edges cling to each other.
00:25:25They protect the railway
00:25:27from violent collisions.
00:25:29They facilitate the flow of water
00:25:31in case of heavy rain
00:25:34Now, let's imagine that
00:25:36we replace them with round stones.
00:25:38They will slide down.
00:25:40Finally, the ballast will collapse
00:25:42and the tracks will collapse.
00:25:44This is the last thing we want,
00:25:46especially if we are a passenger on this train,
00:25:48isn't it?
00:25:50Let's discover some impressive facts
00:25:52about poisons.
00:25:54No, this is not an Nth video
00:25:56with the top 10 most venomous animals.
00:25:58We will mention several here,
00:26:00but this is not where we want to go.
00:26:03There are two glasses in front of you.
00:26:05The first is filled with calcined milk
00:26:07and the other contains the venom
00:26:09of one of the most dangerous snakes in the world,
00:26:11the Aspic viper.
00:26:13According to you,
00:26:15what is the liquid
00:26:17that could have the worst consequences
00:26:19on your health?
00:26:21The right answer is calcined milk.
00:26:23It can cause bloating, indigestion
00:26:25and stomach burns.
00:26:27But if you drink the venom of this snake,
00:26:29nothing will happen.
00:26:31This substance is a particular type of protein
00:26:33and the gastric juices
00:26:35decompose from it like any other food.
00:26:37The toxin contained in the poison
00:26:39is only dangerous in contact with blood.
00:26:41So if you have an injury
00:26:43in your mouth or stomach,
00:26:45then you will have problems.
00:26:47But as long as the toxin remains
00:26:49out of your blood circulation system,
00:26:51you don't have to worry
00:26:53excessively.
00:26:55However, it doesn't always work like that.
00:26:57Some animals secrete a poison
00:26:59that penetrates your body
00:27:01at the slightest physical contact.
00:27:03But venomous creatures must deliver
00:27:05this dangerous substance
00:27:07inside your blood.
00:27:09This is the difference between poison and venom.
00:27:11In the first case,
00:27:13these are animals that can poison you
00:27:15in a passive way,
00:27:17if you touch them for example.
00:27:19They don't make any effort
00:27:21and the poison is constantly released
00:27:23by their body.
00:27:25The venomous androbat frog
00:27:27But everyone is afraid to touch it
00:27:29because its skin secretes
00:27:31one of the most dangerous poisons on Earth.
00:27:33The toxic particles contained
00:27:35in the poison of these batrachians
00:27:37are so tiny that they easily pass
00:27:39through the pores of your skin
00:27:41and cause a violent reaction in your body.
00:27:43But the toxic particles
00:27:45of venomous animals are bigger
00:27:47and can only penetrate your body
00:27:49by injection.
00:27:51These creatures bite and sting
00:27:53to deliver the venom into the blood.
00:27:55Venomous snakes, geese, spiders
00:27:57and other creatures
00:27:59use their venom to attack their prey.
00:28:01Frogs or venomous fish
00:28:03covered with a poisoned skin
00:28:05use these toxins
00:28:07to defend themselves.
00:28:09This is the difference.
00:28:11One of the most venomous creatures
00:28:13in the world is the jellyfish.
00:28:15When it stings, it injects
00:28:17a powerful toxin into its enemy
00:28:19affecting the nervous system
00:28:21and the skin cells.
00:28:23This toxin is harmful
00:28:25not only for marine creatures
00:28:27but also for humans.
00:28:29This toxin acts quickly
00:28:31and can cause serious health problems
00:28:33in a few minutes.
00:28:35One of the most toxic creatures
00:28:37in the world,
00:28:39besides the androbat frog
00:28:41is the jellyfish.
00:28:43Yes, the famous Japanese jellyfish.
00:28:45Many have probably heard
00:28:47that if the cook prepared
00:28:49this fish in an incorrect way
00:28:51this fish is a thousand times more powerful
00:28:53than cyanide.
00:28:55And the amount of poison contained
00:28:57in a single jellyfish
00:28:59is enough to harm
00:29:01several dozen people.
00:29:03When the fish is in danger
00:29:05it swallows air and water
00:29:07and increases in volume.
00:29:09In this state, these thorns
00:29:11containing the toxin
00:29:13become even more dangerous.
00:29:15So never touch this fish
00:29:17if you see it in the sea.
00:29:19The jellyfish
00:29:21is a species
00:29:23of intraspecific competition.
00:29:25It is found in venomous mammals
00:29:27such as the Australian ornithorynch.
00:29:29There are small ergos in their legs
00:29:31that secrete the toxin.
00:29:33An ornithorynch can paralyze
00:29:35an opponent with a single kick.
00:29:37But these animals also use their poison
00:29:39during the competition
00:29:41they have before reproduction.
00:29:43Their bodies strengthen
00:29:45their toxic properties
00:29:47to weaken each other.
00:29:49The one whose poison is the most effective
00:29:51then wins the battle.
00:29:53Some animals have to be bitten and stung
00:29:55to use their venom
00:29:57while others just wait to be touched
00:29:59by someone else.
00:30:01But what about this little creature
00:30:03that releases its poison with an arrow?
00:30:05Here is the ornithorynch.
00:30:07It hides inside its house
00:30:09and waits for a small fish to swim closer.
00:30:11Then it releases
00:30:13a toxic harpoon from its trunk
00:30:15to paralyze the unfortunate fish.
00:30:17Then the ornithorynch swallows
00:30:19its entire prey like an anaconda.
00:30:21The venom of this little animal
00:30:23is also dangerous for humans
00:30:25because it causes serious respiratory
00:30:27disorders, vision,
00:30:29as well as many other problems.
00:30:31On the other hand, the substance contained
00:30:33in the poison of the ornithorynch
00:30:35is used in medicine to make
00:30:37a powerful analgesic.
00:30:39And this is not the only case
00:30:41of an ornithorynch used in medicine.
00:30:43The ornithorynch,
00:30:45in the name of Gila's monster,
00:30:47releases a neurotoxin
00:30:49produced by its salivary glands
00:30:51when it dies.
00:30:53Because of this venom,
00:30:55the bite of this animal
00:30:57is considered one of the most painful
00:30:59in the world.
00:31:01People who have been attacked
00:31:03by a Gila's monster
00:31:05are said to have felt a sensation
00:31:07comparable to lava
00:31:09melting in their veins.
00:31:11Some poisons cause muscle paralysis.
00:31:13Others can cause respiratory
00:31:15problems.
00:31:17And others even increase
00:31:19blood pressure.
00:31:21But why are they all different?
00:31:23All these variations depend
00:31:25on the prey hunted by venomous animals.
00:31:27For example, most vipers
00:31:29feed on small mammals
00:31:31with rapid metabolism.
00:31:33As a result, reptiles have
00:31:35developed a venom that disturbs
00:31:37the coagulation of blood,
00:31:39resulting in a rapid loss of body control
00:31:41for a hare in the race.
00:31:43However, for animals
00:31:45with cold blood,
00:31:47such a strategy would be much less effective.
00:31:49This is why some types of
00:31:51cobras produce a neurotoxic
00:31:53venom that can disturb
00:31:55the transmission inside the nervous system.
00:31:57Such a substance
00:31:59effectively hits the organisms
00:32:01of cold-blooded creatures.
00:32:03All this suggests that venomous
00:32:05and toxic creatures adapt
00:32:07their toxins according to their habitat.
00:32:09This is why the venoms
00:32:11of the same species can vary so much.
00:32:13If a viper
00:32:15bites you in a certain region,
00:32:17an antidote from another region
00:32:19could be of no use to you.
00:32:21In places where survival conditions
00:32:23are more arduous, snakes can
00:32:25develop a more dangerous venom
00:32:27to repel enemy attacks
00:32:29or catch fast prey.
00:32:31But this principle also works
00:32:33in the other direction.
00:32:35A group of snakes in an environment
00:32:37where they can easily catch food
00:32:39and not defend themselves against other animals.
00:32:41This type of snake
00:32:43can eventually become non-venomous.
00:32:45This is because the production of venom
00:32:47is a complex process
00:32:49that requires a lot of energy
00:32:51and resources of the organism.
00:32:53And if the conditions do not require
00:32:55the use of such a substance,
00:32:57then the snakes will stop producing it.
00:32:59This happened with sea snakes.
00:33:01They are some of the most
00:33:03venomous animals on earth
00:33:05who hunt fish in the ocean.
00:33:07As their prey was much faster
00:33:09than them, they had to develop
00:33:11a powerful venom that would paralyze
00:33:13the fish quickly.
00:33:15But a species of sea snake
00:33:17stopped feeding in this way.
00:33:19Instead of hunting fish,
00:33:21they started eating their eggs.
00:33:23This prey does not run away,
00:33:25so that the snakes no longer need venom.
00:33:27After all, they stopped producing it.
00:33:29How many animals on earth
00:33:31can be venomous or toxic?
00:33:33According to the calculations of scientists,
00:33:35about 15 to 20%.
00:33:37But it is likely that this figure
00:33:39is much higher,
00:33:41because we have not fully studied
00:33:43all the biodiversity of our planet.
00:33:45Interestingly,
00:33:47almost all species of animals
00:33:49have a venomous or toxic parent.
00:33:51Even among mammals,
00:33:53the ornithorynchus is not the only
00:33:55venomous creature.
00:33:57The lorillant seems to be an animal
00:33:59that is highly offensive.
00:34:01And yet, this primate from Southeast Asia
00:34:03injects venom with its teeth
00:34:05during a bite.
00:34:07In addition, some species of sea snake
00:34:09produce venom in the same way
00:34:11to paralyze their prey.
00:34:13And vampire bats are the only
00:34:15venomous flying mammals in the world.
00:34:17Okay, we have seen a large number
00:34:19of venomous and toxic animals today.
00:34:21But what were they in the past?
00:34:23Many scientists think
00:34:25that venomous dinosaurs
00:34:27existed millions of years ago.
00:34:29Some studies tend to confirm this hypothesis.
00:34:31Glands and venomous tissues
00:34:33of these formidable reptiles
00:34:35have not survived to this day.
00:34:37But,
00:34:39in the teeth of some dinosaurs,
00:34:41scientists have found
00:34:43small cracks that modern
00:34:45venomous snakes and lizards
00:34:47also present.
00:34:49It is therefore possible that Jurassic monsters
00:34:51used these holes
00:34:53through which they secreted their venom.
00:34:55Landing gear tires
00:34:57do not burst
00:34:59because they are designed for a load
00:35:014 to 5 times higher than those
00:35:03they undergo during landing.
00:35:05The wheel itself can break,
00:35:07but the tire does not burst.
00:35:09This little trick based on behavioral psychology
00:35:11can help you choose the fastest line
00:35:13at the airport.
00:35:15If there are several lines to register,
00:35:17choose the one on the left.
00:35:19You should get to the counter faster
00:35:21this way.
00:35:23Your skin usually becomes a little dry
00:35:25during the flight.
00:35:27This is due to the low humidity
00:35:29in the cabin.
00:35:31Bring a good moisturizing cream
00:35:33with you to keep your skin hydrated on board.
00:35:35Did you know that the pilot
00:35:37and co-pilot of an airplane
00:35:39always eat different meals
00:35:41before a flight?
00:35:43In this way,
00:35:45if one of them has a food poisoning,
00:35:47the other will be able to take control
00:35:49of the aircraft.
00:35:51Airplane tablets
00:35:53are one of the dirtiest surfaces in the cabin.
00:35:55So make sure you wash your hands frequently
00:35:57and clean the tablet
00:35:59with an antibacterial cloth
00:36:01to get rid of all the bacteria
00:36:03that are piling up.
00:36:05If you are sitting on a seat next to the hallway,
00:36:07you can have more space to stretch your legs.
00:36:09Just press the button
00:36:11located under the armrest
00:36:13on the outside.
00:36:15This will raise the armrest,
00:36:17giving you more space for your legs
00:36:19to sink into your ribs.
00:36:21This is one of the reasons
00:36:23why the light in the cabin is dim.
00:36:25Passengers must get used to the darkness
00:36:27in case of an emergency landing
00:36:29at night.
00:36:31In this way,
00:36:33their eyes will already be used to the absence of light,
00:36:35which will facilitate the evacuation.
00:36:37The flight attendants ask you
00:36:39to lift the windows
00:36:41so they can see what's going on outside.
00:36:43This way, they can choose the best way
00:36:45to evacuate passengers in case of emergency.
00:36:47Almost all airliners are white,
00:36:49because this color best reflects the sun's rays
00:36:51and prevents the plane from overheating.
00:36:53Another good reason
00:36:55is that white paint is cheaper.
00:36:57In addition, workers and engineers
00:36:59can easily notice
00:37:01any damage on a white surface.
00:37:03It is preferable to avoid
00:37:05making important decisions during a flight.
00:37:07Your brain does not receive enough oxygen
00:37:09at such a height
00:37:11and this negatively affects its functioning.
00:37:13Chewing gum,
00:37:15the hard candies and the mint candies
00:37:17can help you avoid having your ears
00:37:19clogged during take-off and landing.
00:37:21It is not thanks to the candies themselves,
00:37:23but thanks to the swallowing process.
00:37:25Swallowing also helps.
00:37:27As for chewing gum,
00:37:29it also helps to get rid of this bad breath
00:37:31caused by the rarified air at high altitudes
00:37:33which removes the humidity from your body.
00:37:35The dry air
00:37:37can give you the impression
00:37:39that you are getting cold.
00:37:41The cabin air dries your nose and throat
00:37:43if you have the symptoms of a cold.
00:37:45These symptoms usually disappear
00:37:47just after landing.
00:37:49The water used to make coffee
00:37:51and tea on board is not always very clean.
00:37:53Many companies
00:37:55use very good water filters today,
00:37:57but it is better to ask for bottled water
00:37:59if you are thirsty.
00:38:01This little triangle on the plane's wall
00:38:03above your seat
00:38:05means a lot to the flight attendants.
00:38:07These triangles mark the windows
00:38:09through which you can see the flashing lights.
00:38:11They signal the retraction of the landing brakes
00:38:13and the closing of the flaps.
00:38:15Let's say that the pilots discover that there is a problem.
00:38:17In this case,
00:38:19a flight attendant will rush to the window
00:38:21to check what is going on.
00:38:23And for the passengers,
00:38:25it is simply the best place for photos
00:38:27since you can see the wings perfectly.
00:38:29The seats in the middle of the cabin,
00:38:31above the wings,
00:38:33are the best if you have trouble getting around.
00:38:35This area is more balanced
00:38:37and shakes less during turbulence.
00:38:39If you tend to be nervous
00:38:41during the flight,
00:38:43do a little physical exercise
00:38:45just before getting on the plane.
00:38:47A little training session
00:38:49helps to reduce your stress level
00:38:51and makes sure your body releases endorphins,
00:38:53the hormones of happiness.
00:38:55In addition, this physical activity
00:38:57compensates for the hours you spend sitting without moving.
00:38:59The turbines are placed under the wings
00:39:01because it makes the maintenance of the engines
00:39:03less expensive, faster and easier.
00:39:05Previously, they were placed
00:39:07at the level of the tail.
00:39:09This required expensive equipment
00:39:11and a lot more time to repair them.
00:39:13When we started to install the engines
00:39:15under the wings,
00:39:17the price of tickets dropped.
00:39:19Imagine that you are flying in a Montgolfière.
00:39:21You see the burner system
00:39:23installed under the balloon,
00:39:25also called an envelope.
00:39:27It heats the air inside,
00:39:29which makes the Montgolfière go up.
00:39:31Turbulences aboard a plane
00:39:33are this same hot air,
00:39:35but when it gets colder,
00:39:37the plane goes down
00:39:39and the passengers feel like they are doing roller coasters.
00:39:41A hot air current left by another plane
00:39:43can also cause turbulence.
00:39:45This is a common phenomenon on most flights.
00:39:47But generally,
00:39:49the turbulence is so light
00:39:51that passengers do not feel it.
00:39:53Do you know that planes can fly
00:39:55even after a failure of an engine?
00:39:57Pilots can manage such an emergency
00:39:59and land the plane safely.
00:40:01Passengers can feel a slight inclination
00:40:03during the flight,
00:40:05but in most cases,
00:40:07they do not even know that the plane is flying
00:40:09with a single engine.
00:40:11Your eyes receive oxygen directly from the air.
00:40:13It is not driven by blood.
00:40:15Your eyes can be a little dry during the flight,
00:40:17but drops for the eyes in your luggage
00:40:19will help you keep your eyes moist.
00:40:23It is forbidden to carry large volumes of liquid
00:40:25on board,
00:40:27because some dangerous substances
00:40:29can easily be dissolved in water.
00:40:31If a plane has to sink,
00:40:33its wings become lifeboats.
00:40:35Empty fuel tanks also help
00:40:37the planes to float.
00:40:39Moreover, it can take 10 to 60 hours
00:40:41before the plane sinks.
00:40:43It all depends on the model,
00:40:45the weather conditions
00:40:47and the pilot's skills.
00:40:49These smiling air hostesses
00:40:51that you meet when you enter the cabin
00:40:53usually hide their hands behind their backs.
00:40:55They count the people who enter the plane
00:40:57to make sure that all passengers are on board.
00:40:59Despite what people say
00:41:01about the food in the planes,
00:41:03it is actually not so bad.
00:41:05The problem is your sense of taste,
00:41:07which is no longer as efficient
00:41:09because the air in the cabin makes your mouth dry.
00:41:11It also fades your smell.
00:41:13This is why air hostesses
00:41:15add a lot of spices and salt to their meals.
00:41:19Is it true that your hair grows faster during a flight?
00:41:21Not really.
00:41:23Scientists have not been able to prove it.
00:41:25This myth appeared in the first part of the 20th century
00:41:27when some passengers noticed
00:41:29that their beards had grown more during a flight.
00:41:31It is normal for people to have a headache
00:41:33during a flight,
00:41:35especially just after take-off.
00:41:37You climb to a height higher than Mount Everest
00:41:39in the space of about 10 minutes.
00:41:41These changes occur too quickly
00:41:43for your body to adapt.
00:41:47The aircraft's seatbelts
00:41:49are placed above your belly
00:41:51to prevent you from being projected
00:41:53against the ceiling in case of turbulence.
00:41:55As a result,
00:41:57the aircraft starts to move from top to bottom
00:41:59and your seatbelt holds you firmly.
00:42:01Conversely, seatbelts in cars
00:42:03protect people from horizontal collisions.
00:42:07Aircrafts have a special protection
00:42:09against lightning.
00:42:11Even if it strikes,
00:42:13passengers will not feel it.
00:42:15Aircrafts are covered with an aluminum coating
00:42:17that drives the electric current
00:42:19but does not let it penetrate
00:42:21inside the aircraft.
00:42:23It also provides additional protection.
00:42:25Aircraft seats are uncomfortable
00:42:27because airlines
00:42:29try to fit as many passengers
00:42:31as possible in an aircraft.
00:42:33That is why there is so little space
00:42:35between the seats.
00:42:37Two additional rows means
00:42:3912 more passengers.
00:42:41In addition, airlines make lighter
00:42:43aircraft seats to save on fuel costs.
00:42:45Even an additional weight,
00:42:47apparently insignificant,
00:42:49can cost thousands of euros
00:42:51Your seat has a waterproof coating.
00:42:53It is necessary to prevent a fire
00:42:55from spreading in case of an accident.
00:42:57Airport employees
00:42:59transport unrequited luggage
00:43:01to special centers.
00:43:03If the owner does not show up
00:43:05within three months,
00:43:07the luggage is put up for sale
00:43:09in specialized stores.
00:43:11In the past, you could not use
00:43:13your phone in an airplane
00:43:15because mobile phones were dangerous
00:43:17for navigation.
00:43:19Oxygen masks fall
00:43:21not only during strong turbulence
00:43:23but also when the air pressure
00:43:25inside the cabin changes radically.
00:43:27Passengers do not risk anything
00:43:29if they put on their oxygen mask.
00:43:31But in such cases, they are considered
00:43:33as an emergency.
00:43:35And pilots do their best
00:43:37to go down quickly at a safe altitude
00:43:39so that passengers can breathe
00:43:41without oxygen masks.
00:43:43In December 2014,
00:43:45an entire district of Budapest
00:43:47was hit by an ice crystal.
00:43:49The trees in the area could not
00:43:51stand such pressure
00:43:53and began to bend under their weight.
00:43:55It was a frightening phenomenon
00:43:57called the ice fog.
00:43:59When it happens,
00:44:01the temperature drops considerably,
00:44:03freezing everything around,
00:44:05a bit like the detractors
00:44:07in the Harry Potter saga.
00:44:09And all this thanks
00:44:11to a cross temperature chasing.
00:44:13It does not only affect urban furniture
00:44:15but also small ice crystals.
00:44:17When the temperature drops below
00:44:19less than 10°C,
00:44:21droplets of water in the air freeze
00:44:23and turn into crystals.
00:44:25So far, they remain in a liquid state
00:44:27unless they find something to freeze on.
00:44:29Ice fog is generally formed
00:44:31in the coldest regions of the world,
00:44:33such as the Arctic or the Antarctic.
00:44:35Budapest was, at least, unexpected.
00:44:37Hot and humid gases
00:44:39emitted by vehicles and planes
00:44:41can also create thundering fog.
00:44:43A plane takes off on a cold day
00:44:45and bam!
00:44:47It emits so much thundering fog
00:44:49that the next plane can not see anything.
00:44:51This happens sometimes.
00:44:53It is not the same as ice powder,
00:44:55which is when spare crystals
00:44:57fall from a clear sky.
00:44:59They form when there is a lot of humidity,
00:45:01almost 100%,
00:45:03and the air temperature
00:45:05drops well below 0°C.
00:45:07This creates suspended ice crystals
00:45:09in the air that end up
00:45:11in the lungs.
00:45:17There are many other forms
00:45:19of ice as fascinating as
00:45:21the frost flower.
00:45:23It occurs when the air is cold
00:45:25but the ground has not yet completely frozen.
00:45:27The sap inside the plant stems
00:45:29expands when it freezes,
00:45:31which makes them burst.
00:45:33Once this occurs,
00:45:35the liquid flows,
00:45:37meets the frosted air
00:45:39and forms ice crystals.
00:45:41The light of thunderstorms
00:45:43is another strange and unique phenomenon.
00:45:45When a powerful earthquake
00:45:47of magnitude 8.1
00:45:49struck Mexico in 2017,
00:45:51strange images of green and blue
00:45:53light in the sky
00:45:55began to spread on the Internet.
00:45:57These famous Mexican seismic lights
00:45:59only added to the mystery.
00:46:01Just like lightning bolts,
00:46:03thunderstorm lights
00:46:05are quite rare
00:46:07and just as prodigious
00:46:09as difficult to apprehend for scientists.
00:46:11What complicates things
00:46:13is that observations of lights
00:46:15around earthquakes
00:46:17do not all seem to agree.
00:46:19There are many myths and theories
00:46:21about this phenomenon.
00:46:23Lights can decline in many colors
00:46:25and many forms.
00:46:27Studying our past,
00:46:29historians have isolated 65 stories
00:46:31mentioning such apparitions,
00:46:33some of which date back to the 17th century.
00:46:35On November 12, 1988,
00:46:37for example,
00:46:39people reported that a bright purple sphere
00:46:41floated along the St. Lawrence River
00:46:43in Quebec,
00:46:45only 11 days before a powerful earthquake.
00:46:47In Pisco, Peru,
00:46:49the phenomenon took the form of light
00:46:51captured by security cameras in 2007,
00:46:53shortly before an earthquake
00:46:55of magnitude 8.
00:46:57And in 2009,
00:46:59before another earthquake in Italy,
00:47:01in Aquila,
00:47:03the light was only a few centimeters
00:47:05above paved streets.
00:47:07However, debates persist
00:47:09about the reality of these seismic lights.
00:47:11The Institute of Geological Studies
00:47:13of the United States is cautious
00:47:15because we do not know
00:47:17if these individual testimonies
00:47:19around the time and place
00:47:21of an earthquake
00:47:23really referred to the phenomenon in question.
00:47:25During a study,
00:47:27scientists hypothesized
00:47:29that these lights
00:47:31were released by specific types of rocks
00:47:33during a seismic activity,
00:47:35as if a battery was activated
00:47:37in the earth's crust.
00:47:39Some rocks, such as basalt and gabbro,
00:47:41have tiny crystalline defects.
00:47:43They could potentially release
00:47:45these electric charges.
00:47:47Researchers have estimated that the conditions
00:47:49necessary for the appearance of such lights
00:47:51were only found in less than 0.5%
00:47:53of earthquakes in the world.
00:47:55This could explain their rarity.
00:47:57They also noted that the lights
00:47:59began to appear more often before
00:48:01or during earthquakes than after.
00:48:03A previous study suggested
00:48:05that tectonic pressure
00:48:07could cause a piezoelectric effect,
00:48:09where rocks containing quartz
00:48:11generate powerful electric fields
00:48:13when they are compressed.
00:48:15However, the study of seismic lights
00:48:17remains difficult because they are unpredictable
00:48:19and short-lived.
00:48:23It is time to talk about these mysterious halos
00:48:25that suddenly appear around the moon
00:48:27and the sun.
00:48:29You are walking with a friend
00:48:31and suddenly you see it.
00:48:33It is a warning from Mother Nature.
00:48:35A snowstorm or rain is coming.
00:48:37These halos are formed when billions
00:48:39of tiny ice crystals in the clouds
00:48:41refract the light of the sun.
00:48:43Resist the temptation to admire
00:48:45this prodigy with the naked eye.
00:48:47It can damage your eyes.
00:48:49Take sunglasses and observe it
00:48:51for about forty minutes at most.
00:48:53Nature sends us
00:48:55many early warnings.
00:48:57If the sea mysteriously withdraws,
00:48:59revealing corals and fish,
00:49:01a tsunami could be approaching.
00:49:03Also pay attention to the current
00:49:05of tornadoes on the beach.
00:49:07And sharks could venture further
00:49:09than usual if a storm escapes.
00:49:11You feel your hair stand up
00:49:13and your jewels vibrate.
00:49:15It is lightning that could fall nearby.
00:49:17Quickly seek shelter.
00:49:19Avalanches, green storms and lakes
00:49:21near volcanoes all present potential dangers.
00:49:23The cross-sea is just as dangerous.
00:49:25And practicing speleology
00:49:27during a full moon could cost you your life.
00:49:29If the ocean turns red,
00:49:31avoid swimming there.
00:49:33There could be toxic algae in the water.
00:49:35Animals also detect disasters.
00:49:37If they behave strangely,
00:49:39be careful.
00:49:43A fascinating bluish glow
00:49:45appears around the Matsu Islands
00:49:47during summer nights.
00:49:49It is caused by tiny luminous creatures,
00:49:51known as sea turtles.
00:49:53Tourists love to observe this spectacle.
00:49:55But there is a drawback.
00:49:57It is toxic and increases in size every year,
00:49:59as revealed by a study.
00:50:01Despite its enchanting appearance,
00:50:03the phenomenon is harmful.
00:50:05A team of oceanographers
00:50:07used satellite data
00:50:09to track its progress over 19 years.
00:50:11After analyzing nearly a thousand images,
00:50:13they concluded that it extended
00:50:15to deeper waters.
00:50:17Unfortunately, this expansion
00:50:19has affected sea turtles
00:50:21and even human health.
00:50:23Although dinoflagellates are not harmful,
00:50:25their toxic algae-composed diet
00:50:27releases toxic chemical compounds in the water.
00:50:29This process also exhausts oxygen,
00:50:31endangering marine fauna.
00:50:33The main cause is uncertain.
00:50:35But pollution from agriculture
00:50:37practiced along the Yangtze River
00:50:39seems to play a crucial role.
00:50:41Agricultural rustle
00:50:43introduces nutrients
00:50:45that feed this flora.
00:50:47As a result of the Three Gorges Dam,
00:50:49the size of the phenomenon decreased
00:50:51when the flow of the river decreased.
00:50:53Then, after the completion of the dam
00:50:55and the return of a powerful current,
00:50:57it became more beautiful.
00:50:59Researchers predict that
00:51:01these blue tears will continue to extend,
00:51:03posing a constant threat to marine life
00:51:05and producing more and more luminous waters.
00:51:09A catabatic wind occurs
00:51:11when cold and dense air
00:51:13descends along a mountain slope
00:51:15These winds can be powerful,
00:51:17sometimes reaching the speed of a hurricane.
00:51:19But this is rare.
00:51:21Unlike other descending winds,
00:51:23catabatic winds such as the Adriatic storm
00:51:25or the Santa Ana wind in California
00:51:27come from air that cools
00:51:29in high reliefs like
00:51:31plateaus or mountains.
00:51:33As the air descends,
00:51:35it warms up and its temperature
00:51:37depends on its source region.
00:51:39In Antarctica, catabatic winds
00:51:41play a crucial role in the formation
00:51:43of wind turbines,
00:51:45and in this region,
00:51:47as well as in Greenland,
00:51:49they can be particularly intense
00:51:51and reach the strength of a hurricane.
00:51:53They contribute to unique phenomena
00:51:55such as the dry valleys of McMurdo
00:51:57in Antarctica and are associated
00:51:59with the feared Willy Woes
00:52:01sweeping the archipelago of
00:52:03the Land of Fire and Alaska.
00:52:05The fire of Saint Helm is a natural phenomenon
00:52:07that deserves to be mentioned.
00:52:09It occurs during storms
00:52:11and volcanic eruptions
00:52:13when a powerful electric field
00:52:15reigns over the area.
00:52:17It produces a purple or bluish glow
00:52:19around the masts of ships,
00:52:21aircraft stops or pointed objects.
00:52:23This glow is caused by ionized air molecules
00:52:25and is the most visible
00:52:27in low-light conditions.
00:52:29It is a form of plasma
00:52:31that manifests when the electric field
00:52:33around an object causes the ionization
00:52:35of air molecules.
00:52:37This can occur during storms
00:52:39or when there is a tension
00:52:41between clouds and the ground.
00:52:43Glowing objects facilitate the appearance
00:52:45of the fire of Saint Helm
00:52:47because the electric field
00:52:49is more concentrated.
00:52:51The colors you see,
00:52:53whether blue or purple,
00:52:55come from the fluorescence
00:52:57of nitrogen and oxygen
00:52:59in the Earth's atmosphere.
00:53:01It is similar to the way
00:53:03our neon lamps work
00:53:05but with different gases.
00:53:08The engineers make the wings
00:53:10of the aircraft smooth
00:53:12to allow the air to circulate
00:53:14easily around their surface
00:53:16and reduce resistance during flight.
00:53:18So why did they add
00:53:20these convex yellow hooks?
00:53:22They obviously harm aerodynamics.
00:53:24Of course, but they are also
00:53:26necessary for your safety.
00:53:28Imagine an airplane
00:53:30making an emergency landing
00:53:32in the middle of the sea.
00:53:34Everything goes well,
00:53:36but the passengers have to
00:53:38walk on the wings
00:53:40to get off.
00:53:42They leave the plane
00:53:44by the emergency exits
00:53:46above the wings.
00:53:48Before the door opens,
00:53:50the evacuation slide
00:53:52inflates.
00:53:54The passengers have to
00:53:56walk on the wing
00:53:58and get off on the slide,
00:54:00but the surface of the wing
00:54:02is slippery because of the water.
00:54:04During the evacuation,
00:54:06people can hang onto
00:54:08this rope to avoid falling.
00:54:10With a rope,
00:54:12you can also attach
00:54:14the rescue ropes to the wing
00:54:16so that the currents
00:54:18don't take them away from the plane.
00:54:20The plane can float
00:54:22for 10 to 60 minutes
00:54:24depending on the model,
00:54:26the weather conditions
00:54:28and the pilot's skills.
00:54:30The main exit and the emergency exit
00:54:32During an evacuation,
00:54:34people can panic and accidentally
00:54:36push the air hostesses.
00:54:38To avoid a fall,
00:54:40they cling to their wrists.
00:54:42The seat belt in an airplane
00:54:44has a slightly different function
00:54:46than that of your car.
00:54:48The seat belt protects you
00:54:50from a horizontal shock.
00:54:52When a plane goes through turbulence,
00:54:54it is shaken from top to bottom.
00:54:56Your seat belt prevents you
00:54:58from hitting the ceiling with your head.
00:55:00If a person behaves badly
00:55:02and disturbs the flight,
00:55:04the flight attendants
00:55:06have the right to attach it to their seat.
00:55:08To do this, they use police buttons
00:55:10or plastic clips.
00:55:12This is the maximum that can be done
00:55:14during the flight.
00:55:16Then they report the person
00:55:18to the airport and the police
00:55:20after landing.
00:55:22In case of emergency,
00:55:24oxygen masks fall automatically.
00:55:26They have an additional function
00:55:28Air pressure can change
00:55:30because of turbulence.
00:55:32So, among other things,
00:55:34masks help passengers to stay calm.
00:55:36Your seat is your best ally.
00:55:38The life jacket
00:55:40will prevent you from drowning.
00:55:42In addition, the surface of the seat
00:55:44is made of waterproof material.
00:55:46If water enters the cabin,
00:55:48the seat will prevent you from freezing
00:55:50since it will not be wet.
00:55:52It is also waterproof.
00:55:54The cover can prevent the fire
00:55:56from spreading.
00:55:58Of course, you will probably never
00:56:00use this function,
00:56:02but it is always good to feel safe,
00:56:04isn't it?
00:56:06You can use the tablet in front of you
00:56:08to make a footrest.
00:56:10You just have to attach a belt,
00:56:12a cover or a towel around the table
00:56:14and hang your feet there.
00:56:16You may have noticed black triangles
00:56:18on the wall above the seats.
00:56:20For you, as a passenger,
00:56:22they can indicate the seats
00:56:24where you can take the most beautiful flight photos.
00:56:26But the triangles were not created
00:56:28for your camera.
00:56:30The crew members monitor the aircraft
00:56:32by the windows located under the panels.
00:56:34Let's imagine that the wings are freezing,
00:56:36that the engine is on fire
00:56:38or that the pilot receives a signal
00:56:40about any problem.
00:56:42In this case, the crew quickly heads
00:56:44towards the triangles and evaluates the situation.
00:56:46And you, you are there,
00:56:48sitting under the triangle,
00:56:50looking at the wing and thinking
00:56:52how to attach it to the lower part of the aircraft.
00:56:54They could have installed them above the windows
00:56:56or in the middle.
00:56:58In fact, some aircraft have them in the middle
00:57:00or even higher.
00:57:02And each location makes sense.
00:57:04The engine and the turbines are under the wings.
00:57:06It is much easier to repair them
00:57:08since they are close to the ground.
00:57:10And in case of emergency landing,
00:57:12the wings serve as lifeboats.
00:57:14They help to keep the aircraft on the water.
00:57:16The empty fuel tanks under the wing
00:57:18can also help the aircraft
00:57:20to stay on the surface.
00:57:22But this position also presents some risks.
00:57:24Debris from the runway
00:57:26can get into the turbines.
00:57:28Fortunately, this is unlikely to happen
00:57:30since the runways are carefully cleaned.
00:57:32The aircraft with the wings in the middle
00:57:34have the least resistance to the air.
00:57:36The fighter aircraft
00:57:38and the supersonic aircraft
00:57:40are designed in this way.
00:57:42The big cargo aircraft have their wings
00:57:44at the top of the wing.
00:57:46Thanks to this, the aircraft is closer to the ground
00:57:48and it is easier to load the cargo.
00:57:50In addition, it is safer to land
00:57:52on unprepared runways
00:57:54with high wings
00:57:56because debris will not get into the turbines.
00:57:58The aerodynamics of these aircraft
00:58:00work better thanks to such wings.
00:58:02They have less resistance to the air
00:58:04and deliver goods more quickly.
00:58:06The oxygen inside the masks
00:58:08is a combination of chemical products.
00:58:10Transporting oxygen reserves
00:58:12would be too expensive for the airline.
00:58:14It would take up a lot of space
00:58:16and increase the weight
00:58:18which would lead to an additional
00:58:20consumption of fuel.
00:58:22As a result, there is a chemical oxygen generator
00:58:24located in the panel above your head.
00:58:26A small tank
00:58:28contains barium, sodium
00:58:30and potassium compounds
00:58:32which mix and create a hot chemical reaction
00:58:34that releases oxygen
00:58:36and makes it pass through the mask.
00:58:38The small holes in the hulls
00:58:40prevent the glass from breaking.
00:58:42The air pressure inside the aircraft
00:58:44is higher than outside.
00:58:46The difference is so great
00:58:48that the air can simply break the glass.
00:58:50To avoid this,
00:58:52small holes are drilled.
00:58:54The air passes through and reduces the load on the glass.
00:58:56Moreover, the hulls have an oval shape
00:58:58for the same reason.
00:59:00It is the ideal shape for a uniform air distribution.
00:59:02If they were square
00:59:04or triangular,
00:59:06moisture would accumulate in the corners
00:59:08which could also break them.
00:59:10In addition, all the water is dried
00:59:12The hulls are made of triple glazing.
00:59:14The outer glass
00:59:16holds the pressure.
00:59:18The middle one works like a fuse.
00:59:20The third layer protects the second layer
00:59:22of passengers who like to touch it.
00:59:24Technically, the aircraft could fly
00:59:26with only one layer, but it would be dangerous.
00:59:28An additional protection exists for the wheels.
00:59:30They undergo enormous loads
00:59:32during landing.
00:59:34But don't worry, they won't burst.
00:59:36The tires can withstand
00:59:38a pressure 5 to 7 times higher
00:59:40than what they actually endure.
00:59:42You see the toilet panel on the door?
00:59:44There is a secret compartment below.
00:59:46The crew members can unlock
00:59:48the door from the outside.
00:59:50So don't expect total privacy.
00:59:52Of course, it is forbidden
00:59:54for other passengers to do it.
00:59:56But the cabin crew can open it
00:59:58in case of emergency.
01:00:00When the on-board agents pass through the cabin during the flight,
01:00:02they always touch the upper compartments
01:00:04above the seats.
01:00:06They don't check if they are well closed.
01:00:08Along the compartments,
01:00:10there are handles in the shape of a lace.
01:00:12The air hostesses hang on to it
01:00:14so as not to fall.
01:00:16It is quite practical, especially for those
01:00:18who don't like to touch the passengers' seats
01:00:20while going to the toilet.
01:00:22There is an important reason
01:00:24why the turbines are located under the wings.
01:00:26Previously, they were placed at the level
01:00:28of the tail of the aircraft
01:00:30to improve the aerodynamics of the flight.
01:00:32If one of the engines stopped working,
01:00:34the cabin wouldn't shake so much.
01:00:36In addition, the wings were thinner
01:00:38thanks to the turbines located
01:00:40at the level of the tail,
01:00:42which was also better for aerodynamics.
01:00:44But it turned out that such a location
01:00:46led to additional costs.
01:00:48The engine in the tail was not very practical
01:00:50to maintain.
01:00:52It was high, so it took
01:00:54special equipment and more time
01:00:56to maintain it.
01:00:58And of course, it affected the price of the ticket.
01:01:00So we started to install the turbines
01:01:02under the wings to save money
01:01:04and time.
01:01:06Have you ever noticed a flashing light
01:01:08in the cabin before take-off?
01:01:10It happens when the pilot disconnects
01:01:12the aircraft from the airport's electrical network
01:01:14and switches to the onboard network.
01:01:16This rapid transition can cause flashings.
01:01:22Is the sky like a desert?
01:01:24Can a straight-line aircraft go faster
01:01:26than the speed of sound?
01:01:28Can we repair an aircraft with a piece of adhesive tape?
01:01:30Let's see if your intuitions are good
01:01:32and share your answers in the comments.
01:01:40So here's a first one for you.
01:01:42Straight-line aircraft are more fuel-efficient
01:01:44than your car.
01:01:46True or false?
01:01:48Well, it's true.
01:01:50Commercial flights are more fuel-efficient
01:01:52per person and per kilometer than cars,
01:01:54and for more than a decade.
01:01:56More advanced technologies
01:01:58and a larger number of passengers per aircraft
01:02:00make up almost 74%.
01:02:02As for cars,
01:02:04the decrease was only 57%.
01:02:06OK,
01:02:08what do you think of this?
01:02:10There is no 13 in an aircraft.
01:02:12Now that I think about it,
01:02:14I've never seen a 13A or any letter
01:02:16next to this number on a boarding pass.
01:02:18And you?
01:02:20It's true, but only in part.
01:02:22In countries where the number 13 is considered
01:02:24to be unfortunate, there is no 13.
01:02:26But in other countries,
01:02:28the difference will be different
01:02:30depending on local superstitions.
01:02:32Opening an aircraft door during a flight
01:02:34is a real risk for safety.
01:02:36It sounds pretty scary,
01:02:38but is it true?
01:02:40You can relax, it's just a myth.
01:02:42First of all, the doors are locked,
01:02:44but even if they weren't,
01:02:46no one could open the door of an aircraft during a flight.
01:02:48It's physically impossible.
01:02:50The pressure of the cabin
01:02:52doesn't allow it.
01:02:54When an aircraft is at its cruising altitude,
01:02:56the cabin is pressurized.
01:02:58The difference in pressure
01:03:00between the interior and the exterior
01:03:02is huge.
01:03:04In other words,
01:03:06the pressure inside the cabin
01:03:08pushes the door and prevents its opening.
01:03:10Even better,
01:03:12aircraft doors are so-called
01:03:14plug-type doors,
01:03:16which means that the interior edge
01:03:18is wider than the exterior edge.
01:03:20So it works like the plug
01:03:22of a bathtub,
01:03:24what do you think?
01:03:26If you think it's true,
01:03:28you're absolutely right.
01:03:30The cabin of an aircraft is pressurized,
01:03:32and the humidity is set at 20%.
01:03:34For comparison,
01:03:36in the Sahara desert,
01:03:38the average air humidity is about 25%,
01:03:40and your skin is used to at least 40% humidity.
01:03:42That's why your nose
01:03:44and throat are so dry
01:03:46when you take the plane.
01:03:48Several years ago,
01:03:50someone posted a photo on the Internet
01:03:52of a technician
01:03:54of an airline.
01:03:56He seemed to be repairing
01:03:58a plane with an adhesive tape.
01:04:00So here's the question.
01:04:02Could it be true,
01:04:04or was it just an editing?
01:04:06The answer is not so simple.
01:04:08It was not an ordinary tape.
01:04:10So in part,
01:04:12it's a myth.
01:04:14But it was a kind of adhesive tape
01:04:16known as speed tape.
01:04:18It costs about $700 per roll.
01:04:20It's used for small temporary repairs,
01:04:22waiting to be able to do real repairs.
01:04:24Is it true that pilots
01:04:26avoid the Bermuda Triangle?
01:04:28After all, it has such a bad reputation.
01:04:30Ships and planes
01:04:32seem to disappear in large numbers
01:04:34in this region.
01:04:36It's obviously just a myth.
01:04:38Today, we know that there is no particular
01:04:40danger of flying over the Bermuda Triangle,
01:04:42and planes cross this region
01:04:44every day.
01:04:46Planes generally fly alone.
01:04:48Thanks to automatic piloting systems
01:04:50that do all the work.
01:04:52Myth or truth?
01:04:54What do you think?
01:04:56It's a very widespread myth.
01:04:58Many people think that planes
01:05:00have fully automated mechanisms
01:05:02that allow them to fly alone.
01:05:04And pilots would only be there
01:05:06as reinforcement.
01:05:08But in reality,
01:05:10flying is manual work.
01:05:12It requires constant attention
01:05:14and a competent crew.
01:05:16Is it true?
01:05:18Or is it just a myth?
01:05:20This fact is not a myth.
01:05:22The Concorde
01:05:24could reach a speed of
01:05:262,140 km per hour.
01:05:28It's much faster than the speed of sound,
01:05:30which is about
01:05:321,234 km per hour.
01:05:34It's almost twice as slow
01:05:36as the Concorde.
01:05:38You've probably heard
01:05:40about this terrifying fact.
01:05:42Planes would empty their toilets
01:05:44in mid-flight.
01:05:46But is it true?
01:05:48Fortunately, it's just a myth.
01:05:50There is no ounce of truth in it.
01:05:52Aircraft toilets
01:05:54use a suction system
01:05:56that moves the contents of the toilet
01:05:58to a special reservoir.
01:06:00This is located in the back of the plane.
01:06:02And this reservoir is only emptied
01:06:04after landing.
01:06:06Ah! Here's a tricky question.
01:06:08A plane flying east
01:06:10would reach higher speeds.
01:06:12Does the speed really depend
01:06:14on the direction of the aircraft?
01:06:16And...
01:06:18It's true!
01:06:20This is made possible by high-altitude winds,
01:06:22also known as jet current.
01:06:24They blow at a speed
01:06:26between 241 and 482 km per hour.
01:06:28And since our planet rotates
01:06:30from east to west,
01:06:32planes moving in this direction
01:06:34can use these winds
01:06:36to move faster.
01:06:38Do you think that pilots control
01:06:40the pressure in the cabin
01:06:42to save fuel?
01:06:44It's a myth.
01:06:46If you ask this question to a pilot,
01:06:48he'll tell you it's totally ridiculous.
01:06:50The truth is that the pressure
01:06:52determines the level of oxygen in the cabin.
01:06:54Here's another one.
01:06:56The world's largest air traffic control tower
01:06:58is as high as a skyscraper.
01:07:00Do you think it's true?
01:07:02Or is it still a myth?
01:07:04I know, it's hard to believe,
01:07:06but it's true.
01:07:08To land, a plane needs
01:07:10runway lights and air traffic control beacons.
01:07:12And they are under the responsibility
01:07:14of the control tower.
01:07:16It also manages ground traffic.
01:07:18No wonder
01:07:20such buildings must be very high.
01:07:22Bangkok's new international airport
01:07:24in Thailand
01:07:26has a 132-meter-high tower.
01:07:28Its height is about
01:07:30equal to that of a 40-story building.
01:07:32The construction of this tower
01:07:34cost 18 million euros.
01:07:36I have another difficult question for you.
01:07:38The sensitivity of your taste buds
01:07:40decreases by 30%
01:07:42during a flight.
01:07:44True or false?
01:07:46It's true.
01:07:48The pressure in the cabin
01:07:50associated with the air's dryness
01:07:52thickens your taste buds a bit.
01:07:54But the most curious thing here
01:07:56is that it mostly affects the salty and sweet flavors.
01:07:58If you're served something spicy
01:08:00or bitter,
01:08:02you won't have any problem knowing it.
01:08:04Aircraft manufacturers try to take into account
01:08:06the reduced sensitivity of your taste buds
01:08:08when they prepare airplane meals.
01:08:10They have to modify our good old recipes
01:08:12so that your food tastes better.
01:08:16In case the cabin is depressurized,
01:08:18your oxygen mask is immediately available
01:08:20and you can relax and breathe.
01:08:22You can even use it until the end of the flight.
01:08:24I'd like it to be true, but is it?
01:08:26Unfortunately,
01:08:28it's just a myth.
01:08:30Passengers' oxygen masks usually provide
01:08:32enough oxygen to breathe normally
01:08:34for 10 to 15 minutes.
01:08:36In other words, it's just a temporary solution.
01:08:38But in most cases,
01:08:40this time is enough for the plane to descend
01:08:42to 3,050 meters.
01:08:44And at this altitude,
01:08:46we don't need a mask to breathe.
01:08:48As the planes descend very quickly,
01:08:50additional oxygen is only necessary
01:08:52for a few minutes at most.
01:08:54Besides, oxygen systems
01:08:56are regularly tested during maintenance checks.
01:08:58In addition,
01:09:00passengers' and pilots' oxygen levels
01:09:02do not depend on electricity.
01:09:04Masks use
01:09:06individual oxygen generators.
01:09:08Thus, even if there is an electricity problem on board,
01:09:10the arrival of oxygen will not be cut.
01:09:12Many people say
01:09:14that the plane is the safest means of transport.
01:09:16What do you think?
01:09:18It's a myth.
01:09:20The plane is the second safest means of transport.
01:09:22Studies have shown that the elevator
01:09:24is safer than the plane.
01:09:26Unfortunately, this is not how you can go to the Bahamas.
01:09:28Ok,
01:09:30this last question was a joke.
01:09:32Statistically, the plane is indeed
01:09:34the safest way to travel.
01:09:36So, how many good answers do you have?
01:09:38Tell me in the comments below.
01:09:40I did 8. Not great.
01:09:58I did 8. Not great.
01:10:00I did 8. Not great.
01:10:02I did 8. Not great.
01:10:04I did 8. Not great.
01:10:06I did 8. Not great.
01:10:08I did 8. Not great.
01:10:10I did 8. Not great.
01:10:12I did 8. Not great.
01:10:14I did 8. Not great.
01:10:16I did 8. Not great.
01:10:18I did 8. Not great.
01:10:20I did 8. Not great.
01:10:22I did 8. Not great.
01:10:24I did 8. Not great.
01:10:26More precisely,
01:10:28when their seeds are ripe.
01:10:30Ripe seeds have developed special coatings
01:10:32that protect them when they
01:10:34pass through the digestive system of animals.
01:10:36Why is our skin
01:10:38tingling
01:10:40after spending time in the water?
01:10:42After 5 to 10 minutes in the bathtub,
01:10:44you will notice that small ripples
01:10:46form on your feet and hands.
01:10:48Scientists suppose that this
01:10:50could be the way our body
01:10:52obtains better adhesion
01:10:54when immersed in a slippery environment.
01:10:56Our wrinkled fingers improve
01:10:58our grip on submerged or wet objects.
01:11:00In addition, they channel water
01:11:02in a similar way to the tires
01:11:04for rain on car tires.
01:11:06When you eat something
01:11:08very acidic, you don't feel it
01:11:10only on your tongue.
01:11:12Sometimes your whole face seems to contract
01:11:14so that everyone around can see
01:11:16that you are having a bad time.
01:11:18The bitter taste that causes this reaction
01:11:20is the result of the hydrogen ions
01:11:22that acids release when they mix
01:11:24with saliva.
01:11:26When your mouth detects this sign of an acid,
01:11:28it sends you a message in a spectacular way
01:11:30so that you can't ignore it.
01:11:32It is an evolutionary response
01:11:34that made sense in ancient times
01:11:36because many plants that our ancestors
01:11:38found in nature and then wanted to
01:11:40consume were toxic,
01:11:42especially plants with an acid taste.
01:11:44So even today, your gustatory receptors
01:11:46put you on alert and your face
01:11:48twists uncontrollably
01:11:50when you taste something like this.
01:11:52A lighter color on an airplane
01:11:54is actually heavier
01:11:56than a darker paint.
01:11:58White requires a solid content
01:12:00higher than black to obtain
01:12:02the necessary saturation.
01:12:04However, the higher the solid content is,
01:12:06the heavier the paint will be.
01:12:08This is why white paint is one of the heaviest.
01:12:10But white planes
01:12:12are more effective than black ones,
01:12:14although it also depends on how
01:12:16we define effective.
01:12:18White paint reflects more
01:12:20sunlight than black paint.
01:12:22Different colors absorb
01:12:24different wavelengths of light
01:12:26and white objects heat up
01:12:28more slowly than darker objects.
01:12:30This means that the plane
01:12:32doesn't overheat.
01:12:34If your hot tea tastes weird
01:12:36when you drink it in a plastic cup,
01:12:38don't worry, it's normal.
01:12:40You might think that tea
01:12:42dissolves a part of the plastic,
01:12:44but that's probably not the case.
01:12:46It's just the result of your taste buds.
01:12:48All your senses contribute.
01:12:50That's why strawberry mousse
01:12:52tastes sweeter on a white plate
01:12:54than on a black plate.
01:12:56And that's why you think
01:12:58that crisps are crunchier
01:13:00when you hear those high-frequency sounds
01:13:02while eating them.
01:13:04Likewise, hot chocolate tastes better
01:13:06when you drink it in an orange cup.
01:13:08We are conditioned to drink hot tea
01:13:10in ceramic cups.
01:13:12That's why seeing it in a plastic cup
01:13:14makes us unconsciously expect
01:13:16hot tea from a distributor that doesn't taste good.
01:13:18Pink flames
01:13:20often stay on one leg
01:13:22and a theory states that
01:13:24it helps them keep their body heat.
01:13:26One proof is that
01:13:28they often raise their leg in water
01:13:30than on land.
01:13:32Others think that's how they save energy
01:13:34and not heat.
01:13:36These birds are definitely more stable
01:13:38on one leg when it comes to
01:13:40standing for long periods.
01:13:42That's because they can lock the tendons
01:13:44and ligaments of their legs in a stable position.
01:13:46That means their muscles
01:13:48don't have to work hard
01:13:50to stay in the same place.
01:13:52And that gives them an inimitable look.
01:13:54Why do repetitive sounds
01:13:56annoy us so much?
01:13:58It's simple.
01:14:00They constantly attract our attention
01:14:02and prevent us from focusing on something else.
01:14:04We quickly stop reacting to repetitive sounds
01:14:06like the ticking of a clock.
01:14:08But some are simply
01:14:10too annoying, like a dripping tap.
01:14:12The reason why it bothers us so much
01:14:14is the lack of control.
01:14:16If you know you can stop the sound
01:14:18when you want to, you won't find it
01:14:20as painful.
01:14:22Why do all the planets
01:14:24make circles around the sun in the same direction?
01:14:26It would be great to go back
01:14:284.6 billion years.
01:14:30You could see that space was not empty
01:14:32at the time, even if our solar system
01:14:34was not yet formed.
01:14:36There was a cloud of dust and gas
01:14:38in the place where our sun
01:14:40and the planets are today.
01:14:42This cloud was like a solar nebula
01:14:44and it shaped our solar system.
01:14:46In a simplified way,
01:14:48a nebula is a huge cloud of gas
01:14:50and dust that occupies the space
01:14:52between the stars and helps to form
01:14:54new ones, as well as the planets
01:14:56that gravitate around them.
01:14:58When this nebula collapsed,
01:15:00its center became our sun,
01:15:02while the rest of the matter gathered
01:15:04and created the planets we know today
01:15:06as well as their moons
01:15:08and the rest of the rocky bodies,
01:15:10like asteroids.
01:15:12The matter was spinning fast
01:15:14and the process looked a bit like
01:15:16pizza dough flattening
01:15:18into a increasingly large disk.
01:15:20As the cloud was moving in a certain direction
01:15:22at the beginning, all the planets
01:15:24also kept the same orbital plane.
01:15:26Something massive would have to happen
01:15:28to modify the orbit of a planet
01:15:30and force it to spin around the sun
01:15:32in the opposite direction.
01:15:34Why do some people have such a beautiful voice
01:15:36when they sing?
01:15:38Three elements affect the general range
01:15:40of sounds that come out of your mouth.
01:15:42The strength of your diaphragm,
01:15:44the size of your vocal folds
01:15:46and the shape of the chambers of your sinuses.
01:15:48But making the sound beautiful
01:15:50is largely a matter of practice.
01:15:52At a basic level, you hear a note
01:15:54and you reproduce it with your voice.
01:15:56But the real difference between being
01:15:58simply able to sing a note
01:16:00and having a beautiful voice
01:16:02is the muscular reactions
01:16:04that are mostly unconscious.
01:16:06They adjust your muscular mechanism
01:16:08where you produce your voice
01:16:10according to the emotions you feel while singing.
01:16:12As with other musical instruments,
01:16:14a greater finger amplitude
01:16:16can help you play the piano.
01:16:18But the rest consists of learning
01:16:20these subtle things like the pressure on the keys
01:16:22and the rhythm.
01:16:24Why do dogs hear sounds
01:16:26that are higher than us?
01:16:28Humans hear frequencies up to about 20 kHz
01:16:30and birds hear frequencies
01:16:32up to 45 kHz.
01:16:34Almost all mammals
01:16:36can hear frequencies
01:16:38higher than other vertebrates.
01:16:40Birds hear frequencies
01:16:42up to 12 kHz
01:16:44and reptiles, amphibians
01:16:46and fish hear frequencies
01:16:48up to 5 kHz.
01:16:50Mammals do not need to hear
01:16:52high frequencies to communicate with each other,
01:16:54but to be able to locate
01:16:56the origin of a certain sound.
01:16:58Our brain compares the frequency range
01:17:00of a sound when it reaches each ear.
01:17:02The head goes from the shadow to an ear
01:17:04so that some of the frequencies
01:17:06are absorbed.
01:17:08And our brain absorbs more high frequencies
01:17:10than low frequencies.
01:17:12And the smaller the head,
01:17:14the less it has an effect on low-frequency sounds.
01:17:16This is why the animal must be able
01:17:18to hear high frequencies
01:17:20to hear a wider range of sounds.
01:17:22A mouse must hear up to 90 kHz
01:17:24and an elephant can hear up to 10 kHz.
01:17:26Dogs have a head
01:17:28smaller than ours,
01:17:30so they are in the intermediate category.
01:17:32Why are oceans salty?
01:17:34Chemically speaking,
01:17:36salt is sodium chloride
01:17:38and the salt of the ocean
01:17:40is not only composed of these two elements
01:17:42but also of many other ions
01:17:44such as calcium and magnesium.
01:17:46Most of them start
01:17:48like rocks on the ground.
01:17:50Some factors, such as wind and rain,
01:17:52erode these rocks,
01:17:54and salt gradually wears them away.
01:17:56So we can say that most of the salt
01:17:58in the ocean comes from rocks.
01:18:00The minerals in these rocks
01:18:02are washed away in streams and rivers
01:18:04which transport salt into the ocean.
01:18:06About 85% of the ions in the ocean
01:18:08are sodium and chloride,
01:18:10while magnesium and sulfate
01:18:12account for about 10%.
01:18:14And a part of the salt
01:18:16that is found in the ocean
01:18:18does not remain there.
01:18:20Animals consume a large part of it.
01:18:22Thanks to a regular supply of water
01:18:24from the surface,
01:18:26the levels of salinity are almost constant.
01:18:28The ocean also draws its salt
01:18:30from another source,
01:18:32the hydrothermal fluids.
01:18:34The magma from the depths
01:18:36of the earth's crust
01:18:38heats the depths' events.
01:18:40When they are hot enough,
01:18:42they cause chemical reactions
01:18:44between the sea water
01:18:46and all the minerals in the rocks
01:18:48around the events.
01:18:50This is the place
01:18:52where you find yourself in the world.
01:18:54The most famous survival rule
01:18:56concerning a face-to-face
01:18:58with a bear is to stay still
01:19:00and pretend to be dead.
01:19:02But this rule will not work
01:19:04with all bears,
01:19:06only with grizzlies and brown bears.
01:19:08If you are in North America,
01:19:10you will find them in Alaska,
01:19:12in the state of Washington,
01:19:14Montana, Idaho and Wyoming.
01:19:16Black bears,
01:19:18in California,
01:19:20can be found in
01:19:2240 states of America,
01:19:24a large part of Canada
01:19:26and even some regions
01:19:28of northern Mexico.
01:19:30So, if you go to Yellowstone,
01:19:32you could come across
01:19:34a black bear or a grizzly.
01:19:36But if you are in California,
01:19:38the bear you will come across
01:19:40by accident will most likely
01:19:42be a black bear.
01:19:44And no,
01:19:46it will not be a grizzly.
01:19:48It's complicated, isn't it?
01:19:50If you notice a bump on the shoulders
01:19:52of your impromptu guest,
01:19:54it's a grizzly.
01:19:56Black bears don't have it.
01:19:58A grizzly will also have a more
01:20:00deep face, round ears
01:20:02and long, light-colored claws.
01:20:04The black bear has a straight muzzle,
01:20:06similar to that of a dog,
01:20:08pointed ears and darker claws.
01:20:10There will be an interlude on this
01:20:12a little later.
01:20:14So, if you are sure
01:20:16it's a grizzly or a brown bear,
01:20:18lie down,
01:20:20take a fetal position,
01:20:22bring your knees
01:20:24against your chest
01:20:26and cover your head
01:20:28to show the bear
01:20:30that you are not a threat.
01:20:32These big bears mainly attack
01:20:34when they feel threatened.
01:20:36But you will never be able
01:20:38to outrun them in a race,
01:20:40so don't even try.
01:20:42In 99% of cases,
01:20:44the bear will pass its way.
01:20:46Wait 2 to 3 minutes
01:20:48until you can no longer hear it
01:20:50nearby.
01:20:52It could stay in the parishes
01:20:54to make sure you are not
01:20:56picked up and,
01:20:58if necessary,
01:21:00go on the attack.
01:21:02If you are ready for such an emergency
01:21:04and you have an anti-bear spray
01:21:06on you,
01:21:08remove the safety clip
01:21:10and simply adopt a fetal position.
01:21:12When the bear is retreating,
01:21:14run in the opposite direction
01:21:16to the predator.
01:21:18You got it.
01:21:20If you are dealing with
01:21:22a black bear,
01:21:24it will not stop when it sees you
01:21:26crouching on the ground.
01:21:28And if you don't have anti-bear spray on you
01:21:30and it seems clearly interested,
01:21:32show it who is the boss.
01:21:34Throw stones or your stuff at it
01:21:36and shout loudly, applaud,
01:21:38make yourself look bigger
01:21:40by raising your arms high
01:21:42and shaking your jacket,
01:21:44climb on a rock or a stem.
01:21:46Do everything you can to scare it.
01:21:48Black bears look a lot like
01:21:50these little thugs at school
01:21:52who want your treat.
01:21:54They will often give up if they see
01:21:56that you can defend yourself.
01:21:58If the bear approaches you dangerously,
01:22:00hit it in the nose or eyes
01:22:02and try to confuse it or stun it
01:22:04to make this unwanted hiking companion
01:22:06and just sit away and watch you.
01:22:08Try to move away very slowly.
01:22:10Move laterally with a slight angle
01:22:12so as not to stumble
01:22:14by retreating far from the danger.
01:22:16In this way, the bear will not think
01:22:18that you are trying to escape
01:22:20and will not be incited to chase you.
01:22:22Speak calmly out loud
01:22:24to show it that you are a human.
01:22:26Singing can also help.
01:22:28Who knows, maybe it will also know the melody.
01:22:30Avoid direct visual contact with the animal
01:22:32and never stand between
01:22:34a bear and its mother.
01:22:36Do not panic if the bear stands on its hind legs.
01:22:38This is not an aggressive demonstration.
01:22:40If you ever plan to visit
01:22:42a region populated by polar bears,
01:22:44do not go there without means of dissuasion.
01:22:46Like a tank, for example.
01:22:48Bad polar bears, in good health,
01:22:50weigh half a ton,
01:22:52are 2 meters tall on their hind legs
01:22:54and can hunt their prey
01:22:56up to 40 km per hour.
01:22:58A group of 3 or more people
01:23:00can be enough to intimidate any bear.
01:23:02So, do not go out alone.
01:23:04Walk with other people
01:23:06and speak loudly during your hike
01:23:08to indicate that you are a group of humans.
01:23:10Do not forget that all polar bears
01:23:12are not eager predators
01:23:14to make you their breakfast.
01:23:16Some of them simply vacate their occupations.
01:23:18If you see one with his head down,
01:23:20sneaking,
01:23:22without trying to go elsewhere
01:23:24but clearly focusing on you,
01:23:26this is where you should worry.
01:23:28Move away slowly from the bear,
01:23:30and use your means of dissuasion
01:23:32only if the bear comes close to you.
01:23:36Some claim that ammonia
01:23:38is an excellent repulsive for bears.
01:23:40They really do not like its smell,
01:23:42so if you soak a few wipes
01:23:44and throw them in the garbage,
01:23:46they should not be interested
01:23:48in your trash.
01:23:50And if you meet a bear in nature
01:23:52and it does not seem to be so interested in you,
01:23:54ammonia could help you repel it.
01:23:56However, ammonia can also
01:23:58damage its nasal voices,
01:24:00depriving the animal of its odor,
01:24:02which means it will no longer be able
01:24:04to find its food.
01:24:06This could also annoy a bear
01:24:08who did not plan to attack you
01:24:10and push it to do so.
01:24:12Everything that has an interesting smell
01:24:14for bears, starting with your food
01:24:16and your garbage,
01:24:18will attract their attention
01:24:20and push them to come inspect your tent.
01:24:22So cook far from the camp
01:24:24and do not spread garbage.
01:24:26The use of anti-bear sprays
01:24:28could be counterproductive.
01:24:30The peppered products they contain
01:24:32may remind them of the smell of food
01:24:34and could be a way to attract bears.
01:24:38If you notice a bear standing
01:24:40on the side of the road,
01:24:42resist the urge to stop
01:24:44to take pictures.
01:24:46Stay at least 100 meters away
01:24:48and park in a safe place.
01:24:50Bears on the side of the road
01:24:52quickly get used to humans
01:24:54and are more likely to approach
01:24:56campsites and picnic areas
01:24:58in search of human food.
01:25:00People who live in the mountains
01:25:02or close to nature
01:25:04are used to the visit of bears
01:25:06and generally do not fear them.
01:25:08Douglas Harder has thus noticed
01:25:10a black bear mother and her two children
01:25:12emptying the bird feeder on his terrace.
01:25:14He also happened to go home
01:25:16after a while
01:25:18to see that a bear had entered
01:25:20his kitchen through a partially open sliding door.
01:25:22The intruder had scratched a wall
01:25:24and chipped some treats
01:25:26before fleeing.
01:25:28Harder had just finished cleaning
01:25:30after the bear when a bear
01:25:32pushed his head through his cat litter.
01:25:34These photos went viral online.
01:25:38Kristen Jones, on the other hand,
01:25:40was visiting her parents in North Carolina
01:25:42and had decided to do yoga
01:25:44on the bank of a lake nearby.
01:25:46She was wearing headphones
01:25:48and did not hear the bear
01:25:50suddenly she felt someone sniffing
01:25:52and licking her neck.
01:25:54She thought it was her neighbor's dog
01:25:56and extended her arm to caress him
01:25:58which scared the animal.
01:26:00Kristen managed to take
01:26:02some pictures of the bear
01:26:04fleeing, although no one
01:26:06believed the story of this licker.
01:26:08She remembers this moment
01:26:10as the scariest in her life
01:26:12and hopes it will never happen again.
01:26:14As for the bear, he was very likely
01:26:16in the parishes in search of food,
01:26:18in trash cans and on people's terraces.
01:26:22Scientists who observe polar bears
01:26:24note how incredibly intelligent
01:26:26these animals are.
01:26:28The members of Polar Bears International
01:26:30took hundreds of pictures
01:26:32to study these animals closely.
01:26:34Before using a special cage,
01:26:36they took their pictures
01:26:38using a device fixed to the end
01:26:40of a long pole which was lowered
01:26:42to a certain height.
01:26:44One day, the flash of the camera
01:26:46flashed right in front of a bear's face.
01:26:48Movies, TV shows
01:26:50and documentaries show us two kinds
01:26:52of situations. You board a cruise ship
01:26:54and you go on a trip.
01:26:56During a storm, the ship sinks.
01:26:58The good news is that you survive.
01:27:00The bad news is that you are
01:27:02in the middle of the sea.
01:27:04In the second situation, you are in a plane.
01:27:06There is a problem. The engines catch fire
01:27:08and the plane crashes into the ocean.
01:27:10The waves surround you and you don't know
01:27:12what to do. In both cases,
01:27:14there is a great chance that you will be saved.
01:27:16Flight controllers usually know
01:27:18very quickly when a plane crashes.
01:27:20And it's the same with big ships.
01:27:22Modern navigation
01:27:24and communication methods help
01:27:26the rescuers to find you quickly,
01:27:28especially if several people are in trouble.
01:27:30But let's imagine
01:27:32a much more terrifying situation.
01:27:34You are in a seaside resort and you tell
01:27:36your friends that you want to eat something.
01:27:38You go to the beach, you buy food
01:27:40and you decide to have lunch at sea.
01:27:42You loosen a catamaran
01:27:44or a small boat, you move away from the shore
01:27:46and you fall asleep.
01:27:48The intense heat wakes you up.
01:27:50You are in the middle of the ocean.
01:27:52You don't know where the shore is
01:27:54or how long you've been there.
01:27:56Fortunately, you have your phone.
01:27:58But the bad news is that it no longer has a battery.
01:28:00At this stage, you can start
01:28:02to worry. But even if it's a cliché,
01:28:04above all, don't panic.
01:28:06The waters around you can make you nervous.
01:28:08To have the impression of being
01:28:10a tiny thing in a huge sea
01:28:12can cause a feeling of terror.
01:28:14But you have to understand that panicking
01:28:16will only make things worse.
01:28:18You have to keep your cool and think.
01:28:20First of all, your situation is
01:28:22advantageous because you have a boat.
01:28:24Some people end up stuck
01:28:26at sea without anything.
01:28:28Your chances of surviving are not so bad.
01:28:30By the way, if you are in the water without a boat
01:28:32but you have pants,
01:28:34you can easily make a life jacket.
01:28:36Just tie the two legs
01:28:38of the pants.
01:28:40Then shake the water with your hand to create bubbles
01:28:42and make it penetrate
01:28:44the pants.
01:28:46After that, grab its upper part to prevent the air
01:28:48from escaping and place it around your neck.
01:28:50Here you have a life jacket.
01:28:52But let's go back to your boat stuck at sea.
01:28:54You don't have pants,
01:28:56just a short and a t-shirt.
01:28:58You have a piece of burrito
01:29:00and a little water in a bottle.
01:29:02Above all, don't drink it all at once.
01:29:04Try to make it last as long as possible.
01:29:06Also know that
01:29:08you must not drink seawater.
01:29:10The salt it contains will make you even more thirsty
01:29:12and your body will be in danger.
01:29:14You must collect fresh water when it rains.
01:29:16Keep your bottle open
01:29:18and let the rain wet your clothes.
01:29:20The important thing is that if you swam
01:29:22in the sea in these clothes,
01:29:24they will be covered with a thin layer of salt.
01:29:26So, first,
01:29:28let the rainwater soak your t-shirt
01:29:30then strain it to remove all the salt.
01:29:32After that,
01:29:34you can use your clothes
01:29:36to collect drinking water.
01:29:38You now have a whole bottle of fresh water.
01:29:40Take a few sips several times a day
01:29:42and you will have enough for a week.
01:29:44Now you have to catch some fish.
01:29:46The good news is that
01:29:48the marine creatures have approached you.
01:29:50The boat attracts their attention.
01:29:52They come to you out of curiosity
01:29:54or to use your boat as a shelter.
01:29:56You just have to catch your lunch.
01:29:58If you wear shoes,
01:30:00use your laces or tear a piece of fabric
01:30:02to make a small rope.
01:30:04Tie a piece of your burrito
01:30:06or any other object to the end of the rope
01:30:08and start fishing.
01:30:10Now you have food and water
01:30:12and nothing to fear,
01:30:14except for sharks.
01:30:16The colors live
01:30:18or a drop of blood can attract them.
01:30:20You can scare them by screaming
01:30:22and beating the water with your hands
01:30:24making noise.
01:30:26They will think they have come
01:30:28to a very dangerous beast,
01:30:30but it is rather something
01:30:32that we see in the movies.
01:30:34But if you have to do something,
01:30:36it is better to give them a blow on the nose
01:30:38than to panic in the water.
01:30:40So you have fish, water
01:30:42and a little authority.
01:30:44Life is beautiful,
01:30:46but you are missing something.
01:30:48Ah yes, you have to join
01:30:50the mainland to survive.
01:30:52You can attract the attention
01:30:54of a plane or a passing ship.
01:30:56Don't worry if you don't have
01:30:58a gadget to reflect the light of the sun
01:31:00and use this beam as a signal.
01:31:02There is a good chance that people
01:31:04on a ship or even pilots
01:31:06in a plane see it.
01:31:08Keep your phone ready
01:31:10so as not to miss an opportunity.
01:31:12In fact, many boats are equipped
01:31:14with lighting rockets and life jackets
01:31:16equipped with reflectors.
01:31:18Use them at night
01:31:20and people will see you from afar.
01:31:22Alas, your tourist boat does not have one.
01:31:24Your phone is therefore your only way
01:31:26if you don't see anyone who could save you.
01:31:28If you don't see the coast,
01:31:30look at the water.
01:31:32The closer you are to the shore,
01:31:34the clearer it will be,
01:31:36so if you can distinguish a less dark shade,
01:31:38you will know where to go.
01:31:40And pay close attention to the direction of the waves.
01:31:42They are heading towards the shore.
01:31:44Also look at the sky.
01:31:46If you see seagulls
01:31:48or other birds, follow them.
01:31:50Sooner or later,
01:31:52they will lead you to the beach.
01:31:54The main thing here is the sun.
01:31:56It always rises to the east
01:31:58and sets to the west.
01:32:00At noon, it shines from the south
01:32:02located in the northern hemisphere.
01:32:04And located in the southern hemisphere,
01:32:06the sun is north in the middle of the day.
01:32:08Focusing on these signs
01:32:10will allow you to understand your position
01:32:12and to head towards the coast.
01:32:14But what to do if you still don't know
01:32:16which direction to take?
01:32:18Try to remember a morning in your hotel.
01:32:20Remember where the sun was
01:32:22For example, if you were on the balcony
01:32:24and you saw the sunrise
01:32:26on the right of your windows,
01:32:28it means you were facing south.
01:32:30In your boat, imagine the orientation of your hotel
01:32:32or your house relative to the morning sun.
01:32:34And head in that direction.
01:32:36Other signs can tell you
01:32:38where the coast is.
01:32:40If the water becomes muddy,
01:32:42it means there is the mouth of a nearby river.
01:32:44Move following this muddy water.
01:32:46A greenish hue in the clouds
01:32:48also indicates that the earth is close.
01:32:50So you drifted for several days
01:32:52and exhausted all your water reserves.
01:32:54At some point,
01:32:56you hear the cry of the seagulls.
01:32:58You open your eyes and you see them.
01:33:00You follow them and you notice muddy water.
01:33:02You are hungry, exhausted and thirsty,
01:33:04but happy
01:33:06because you know the coast is close.
01:33:08As the night falls,
01:33:10you see the lights of the city in the distance.
01:33:12In the morning, you reach the mainland
01:33:14and you return to the hotel.
01:33:16There are several ways to survive.
01:33:18The most important is to stay calm.
01:33:20Some people survived
01:33:22several weeks and even a year
01:33:24in the sea.
01:33:26Some floated on a broken ship,
01:33:28a pneumatic channel or the debris of a boat.
01:33:30But each time,
01:33:32the desire to live,
01:33:34the will and the hope helped them to hold on.
01:33:38Let's start with some crazy hypotheses.
01:33:40What would happen
01:33:42if we could miraculously visit
01:33:44each of our ancestors in chronological order?
01:33:46Could we talk to them
01:33:48and establish a real connection?
01:33:50And how long
01:33:52could we go back
01:33:54while keeping in touch with them?
01:33:56Well, let's see.
01:33:58The primates were
01:34:00the cousins of the other mammals.
01:34:04About 85 million years ago,
01:34:06during the period of the upper Cretaceous,
01:34:08they decided to follow their own path
01:34:10and became the first
01:34:12representatives of their species.
01:34:16Human evolution is very complex
01:34:18and we cannot trace
01:34:20distinct lines where it precisely began.
01:34:22But we will start with
01:34:24the Hominini.
01:34:26The Hominini are a group of primates
01:34:28that include all the species
01:34:30leading to Homo sapiens.
01:34:32Very well.
01:34:34Imagine that you have climbed
01:34:36in your super machine to go back in time
01:34:38and that you have landed in the past
01:34:40at the time when the Hominini
01:34:42roamed the Earth.
01:34:44You would notice these strange creatures
01:34:46walking around with their small velvet bodies,
01:34:48their puzzling faces
01:34:50and their big round eyes.
01:34:52They may seem a little different from us,
01:34:54but that's what makes all their charm.
01:34:56They were these excellent
01:34:58climbers, these incredibly
01:35:00curious people around.
01:35:02They enjoyed fruits, nuts
01:35:04and everything they could find.
01:35:06And yes, surprisingly, humans
01:35:08are not carnivores by nature.
01:35:10Originally, we were all
01:35:12vegetarians.
01:35:14Of course, with them you can make a cross
01:35:16on any form of adequate communication.
01:35:18But primates are
01:35:20particularly intelligent.
01:35:22So you just need to have some
01:35:24mime talent.
01:35:26Calm them down with friendly gestures
01:35:28and they will be delighted to meet
01:35:30a traveler of the future like you.
01:35:34These Hominini were
01:35:36curious by nature,
01:35:38so they would probably be very interested
01:35:40in meeting you.
01:35:44Let's move on to Homo habilis
01:35:46and Homo erectus.
01:35:48Their period, the Stone Age,
01:35:50began about 2,600,000 years ago.
01:35:52As you can guess,
01:35:54that's when we started
01:35:56using stone tools.
01:35:58This age lasted about
01:36:003,400,000 years
01:36:02and ended between
01:36:044000 and 2000 BC.
01:36:06It ended with the advent of metallurgy.
01:36:08Homo habilis,
01:36:10or the skillful man,
01:36:12was a bit like the Stone Age MacGyver.
01:36:14These ingenious creatures
01:36:16were the first to use
01:36:18stone tools.
01:36:20Homo erectus, for his part,
01:36:22was the man standing.
01:36:24His appearance is a little more recent.
01:36:26And as his name suggests,
01:36:28he was the first to walk on two legs
01:36:30like us.
01:36:32He certainly had a slightly different appearance
01:36:34than modern humans,
01:36:36with a bipedal look.
01:36:38So, what was he like?
01:36:40Well, we're talking about a real survivor.
01:36:42Homo erectus loved to explore the world
01:36:44and tinker with all kinds of things.
01:36:46He made rudimentary stone tools,
01:36:48like sharp stones to cut and scratch.
01:36:50He was essentially
01:36:52the first inventor in history.
01:36:54Homo erectus was also
01:36:56adventurous.
01:36:58He left Africa and traveled to distant lands,
01:37:00discovering new territories
01:37:02in the process.
01:37:04Homo erectus was one of the first
01:37:06to explore continents like Europe and Asia.
01:37:08He lived in caves,
01:37:10or simple shelters made of branches
01:37:12and animal skins.
01:37:14And let's not forget their innate sense of fashion.
01:37:16Their clothing was already
01:37:18made of skin and leaves.
01:37:24You wouldn't believe that they were walking
01:37:26on their thumbs all day long.
01:37:28They were hunter-gatherers,
01:37:30perpetually in search of juicy fruit,
01:37:32even killing some animals.
01:37:34How did they communicate with each other?
01:37:36Well, they didn't use simple gestures
01:37:38or body language
01:37:40to understand each other.
01:37:42So, if you met a Homo habilis
01:37:44or a Homo erectus,
01:37:46you would have a more muscular exchange.
01:37:48You could display our latest technology
01:37:50to amaze them
01:37:52and teach them new tricks.
01:37:54The next on our list
01:37:56are Homo heidelbergensis
01:37:58and Neanderthals.
01:38:00Homo heidelbergensis was, in a way,
01:38:02the older cousin of the Neanderthals
01:38:04and the modern man.
01:38:06He lived about 8 to 200,000 years ago.
01:38:08These men were strong
01:38:10and robust,
01:38:12with bigger brains than their ancestors.
01:38:14They were experts in
01:38:16tool-making
01:38:18and they always liked to explore new places.
01:38:22The Neanderthals lived
01:38:24in Europe and Asia
01:38:26between 400,000 and 40,000 years ago.
01:38:28They were very smart
01:38:30and remarkably well adapted
01:38:32to the cold weather.
01:38:34With their powerful body,
01:38:36their muscular muscles
01:38:38and their big noses,
01:38:40they could face the harshest winters.
01:38:42Homo heidelbergensis
01:38:44and the Neanderthal man
01:38:46were excellent hunter-gatherers.
01:38:48They hunted mammoths
01:38:50and other large carnivores
01:38:52by means of their own design.
01:38:54But they didn't care
01:38:56only about their survival.
01:38:58They also knew
01:39:00how to have fun.
01:39:02The Neanderthals had
01:39:04an artistic fibrousness
01:39:06and showed their emotions
01:39:08as well as their attachment to each other.
01:39:10With these guys,
01:39:12you would only have to draw pictures on the ground,
01:39:14dance and make gestures.
01:39:16They would surely understand the idea.
01:39:18And finally,
01:39:20here is Homo sapiens.
01:39:22Imagine this.
01:39:24You wake up in a cave with your family
01:39:26in the heat of a blazing fire.
01:39:28This cave is rather comfortable,
01:39:30isn't it?
01:39:32Except that this situation is not permanent.
01:39:34You are part of a nomadic tribe
01:39:36that moves where the food is.
01:39:38Well,
01:39:40but at least you have some ingenious tools
01:39:42to survive.
01:39:44So grab your superb handcrafted spear,
01:39:46made by observing the others
01:39:48or maybe your own crew.
01:39:50It's time to go hunt the mammoth.
01:39:52And if the mammoths
01:39:54are not cooperative,
01:39:56you just have to collect nuts,
01:39:58berries and eggs.
01:40:00The humans of the Stone Age were members of a gastronomic family.
01:40:02They knew how to make oatmeal
01:40:04and make it with wild onions
01:40:06and mustard seeds.
01:40:08There were also artists among them.
01:40:10Using mineral pigments and bones,
01:40:12they created superb paintings
01:40:14and even flutes
01:40:16to cheer up their campfire.
01:40:18You can always express yourself
01:40:20only by body language
01:40:22and facial expressions.
01:40:24But the Homo Sapiens
01:40:26were smarter than their ancestors.
01:40:28So we could teach them
01:40:30simple gestures
01:40:32and their meanings,
01:40:34like raising your hands to say
01:40:36mammoth or something else.
01:40:38Maybe try to perform
01:40:40a funny dance in front of them.
01:40:42It is certain to attract their attention,
01:40:44but it would not be the only way to communicate.
01:40:46The men of the Stone Age
01:40:48loved to draw and play music.
01:40:50So you would not have any trouble
01:40:52joining the party,
01:40:54showing your artistic talents
01:40:56with one or two sketches
01:40:58or whistling their few melodies.
01:41:00Do not worry,
01:41:02they will be impressed by your skills
01:41:04even if you are not much more talented than them.
01:41:06But tools are clearly
01:41:08the shortest way to their hearts.
01:41:10If you offered them some practical gadgets
01:41:12of our time,
01:41:14just create a simple tool
01:41:16able to make their life easier.
01:41:18And they will appreciate you instantly.
01:41:22So,
01:41:24even if you will probably not engage
01:41:26in a deep philosophical debate
01:41:28with these people of the Stone Age,
01:41:30you can still have a good time.
01:41:32Learning is the way to success.
01:41:34Moreover,
01:41:36even if life was shorter at the time,
01:41:38about thirty years on average,
01:41:40it was still long enough to find a partner
01:41:42or a progenitor.
01:41:44However,
01:41:46the options of meeting
01:41:48could be a bit limited.
01:41:50So let's leave this subject for another time.
01:41:52You will just have to hold your axe
01:41:54close to your hand during the night
01:41:56because, well,
01:41:58it was not uncommon for our ancestors
01:42:00to eat each other and cut each other.
01:42:02And that, it sucks.
01:42:04Let's finish our journey with the Bronze Age,
01:42:06just for fun.
01:42:08This period lasted from 3300
01:42:10to 2200 B.C.
01:42:12And guess what?
01:42:14The people of this time
01:42:16only swore by this solid metal
01:42:18called bronze.
01:42:20This is the time when we became creative
01:42:22and began to use this alloy
01:42:24to make all kinds of things.
01:42:26Bronze is a mixture
01:42:28of copper and tin,
01:42:30which makes it harder
01:42:32and more durable than anything else
01:42:34of this period.
01:42:36Formidable civilizations
01:42:38made their own bronze
01:42:40by melting copper
01:42:42and mixing it with tin
01:42:44or exchanging it
01:42:46with their neighbors.
01:42:48Thus, when you visit this ancient land,
01:42:50you will be amazed
01:42:52by the animated cities of the Bronze Age,
01:42:54adorned with massive metal statues,
01:42:56picturesque markets
01:42:58and grandiose temples dedicated to the gods.
01:43:00It was during the Bronze Age
01:43:02that we finally developed languages
01:43:04and writing.
01:43:06Mesopotamia and Egypt
01:43:08opened the ball with their
01:43:10wonderful cuneiform and hieroglyphic
01:43:12alphabets,
01:43:14the first writing systems ever invented.
01:43:16They were, so to speak,
01:43:18the kings of calligraphy.
01:43:20Remember that the language
01:43:22could be a little different,
01:43:24you would only hear unknown words.
01:43:26But with these humans,
01:43:28you can at least use drawings,
01:43:30singing and many other things
01:43:32to communicate.
01:43:34So,
01:43:36don't forget to cherish our past
01:43:38while appreciating the wonders
01:43:40of our modern world.
01:43:42Stay tuned!