Learn One Thing A Day

Every once in a while Google/Youtube succeeds in giving me some good recommendations about new channels/videos I could be interested in. This is was exactly the case with Mathologer , a really interesting math channel, that I warmly recommend too. In the episode How not to die hard with math Burkard Polster analyses the problem which appeared in Die Hard with a vengeance (1995, Bruce Willis & Samuel L. Jackson). I wouldn't be surprised if the same problem would be chosen for testing the skills of an applicant during a job Interview! Enjoy!

The word "avocado" originates from the Nahuatl word āhuacatl , that means testicle. Because, you know, avocado fruits hanging from a tree look like testicles!  (source: sevaniskin.com ) Moreover, since guacamole ( āhuacamolli ) means avocado sauce, well...draw your own conclusions! ;) There is another interesting fact about the avocado but for that I recommend you the video from scishow! Enjoy!

The Dollar sign $ , where does it come from? The symbol started to appear in 1770 and there are at least two possible explanations for it. 1) The first one is that it is an abbreviation of the word "Pesos". The evolution would have been P eso s -> PS -> $ 2) Another alternative explanation is that $ comes from merging of the letters U and S, coming from USA . It is also said that it was introduced by Oliver Pollock, an American patriot, in 1778.   Wikipedia puts it nicely in a figure    More info on wikipedia :)

Did you that in 1742, the Swedish astronomer Anders Celsius (1701–1744), created the a temperature scale which was the REVERSE of what we call today the "Celsius" scale: indeed, 0 represented the boiling point of water and 100 its freezing point!

I have just learned that in Australia there is a pink lake! It is the Hillier Lake and it's AWESOME! ( http://touristmeetstraveler.com/ ) The most notable feature of the lake is its pink colour. The colour is permanent, and does not alter when the water is taken in a container. Interestingly, the source of the pink colour has not been definitively proven in the case of Lake Hillier, but the pink colour could be due to red halophilic bacteria in the salt crusts. Despite the unusual hue, the lake exhibits no known adverse effects upon humans. From above, the lake appears a solid bubble gum pink  If you want to see where the Hillier Lake is, take a look on Google Maps From wikipedia

Today I learned that there is a star, called HD 140283 , or more easily, the " Methuselah Star " or the " Genesis Star " that appears to be old just as the Univese itself! (Image from Wikipedia ) It is 190.1 light-years away, its size is 1.4 times the Sun and it's age is 14.46 ± 0.8 billions of years. As stated, its age is pretty impressive, condisidered that the age of the Universe is only 13.798 ± 0.037 billions of years! Within the error bars, this star is just old as the Universe itself!!! The star must have formed soon after the Big Bang, and it has perhaps the largest age purported to any star. Other info about the Mathuselah are available at the wikipedia link .

We already know ( right? ), that an adult human body has 206 bones, (babies have about 300), but did you know that 26 bones are located in each foot and ankle, i.e. 25% of ALL your bones are actually in your feet! (52/206=25.2 %)!!! (source wikipedia ) These bones contain in 33 joints (per foot), with over one hundred muscles, tendons, and ligaments in each foot also! Read more at http://www.omg-facts.com/Science/25-of-your-bones-are-located-in-your-fee/34895#QdL2SvlXIDw04Wm4.9 The human body contains 206 bones total. 26 bones are located in each foot and ankle, meaning that there are 52 bones altogether in your feet. That’s a quarter of the total bones in your body! Read more at http://www.omg-facts.com/Science/25-of-your-bones-are-located-in-your-fee/34895#QdL2SvlXIDw04Wm4.99 The human body contains 206 bones total. 26 bones are located in each foot and ankle, meaning that there are 52 bones altogether in your feet. That’s a quarter of the total bones in your body! Read m...

In the last week from a colleague and in the The Big Bang Theory (Season 7 episode 11) I heard a nice and simple English expression that uses the American and British pronunciations of the word tomato. The expression by itself is very simple: " Tomato tomato " but what matters is the prounciation: " toe-MAY-toe , toe-MAH-toe " The meaning of the "tomato, tomato" is to express more clearly that two things supposed to be different, aren't or just have minor differences. It originates from the 1937 song "Let's call the whole thing off" by George Gershwin: " ... you like tomatoes [toe-may-toes] and I like tomatoes [toe-mah-toes]... " (from http://www.ishs.org/ ) Reference: http://en.wiktionary.org/wiki/tomato_tomato

The loudest animal(s) on Earth? In terms of pure power nobody beats the Blue Whale ! Its whistles can indeed reach 188 dB! How big is this number?  Well, just consider that a human whisper at 1 m is about 20 dB, a conversation is 60-70 dB and a Jet Engine is 140 dB. What is the threshold of pain for a human ear? 120-130 dB! And at 160 dB your eardrum will rupture! The phenomenal blue whale whistles have been recorded more than 500 miles (805 kilometers) away! This is pretty much the distance between San Francisco and San Diego! Amazing! However the poweful whistle is not the only thing special about the Blue Whale. As I wrote in a previous post , it is also the largest animal that ever lived on Earth! Yes, even larger than the largest dinosaur! (Photograph by Flip Nicklin, National Geographic ) Another every interesting and loud animal is the Snapping Shrimp .  (Photograph from WaterFrame/Alamy, National Geografic ) Even though it doesn't sing as the wh...

Today, I received from a vending machine a coin that, at a first look, resembles a 2 Euro but definitely is not, and, as you can imagine it is also less worth compared to a 2 Euro (I suspect this was the all point of inserting it into the vending machine!) Anyway, I made some digging over the World Wide Web and I learned something interesting that's worth to write about. First of all: the coin looking like a 2 Euro is a 10-baht coin (the Thai currency) and, as you can see, the similarity is pretty strong... (image receiving it as change with other coins!) (For the comparison 2 Euro vs 10 baht,  I  used the German 2 Euro, showing the German coat of arms, i.e. the German eagle) The similarity is deeper that you can suspect ... Value         2 euro            10 baht Mass           8.4 g     ...

Today I learnt that the Blue Whale is not not only the largest living animal but - probably - also the largest one to have ever lived! They live  worldwide and are considered endangered by IUCN ( International Union for Conservation of Nature ) due to the human activity, most notably the pollution and the fisheries interactions. Here is some impressive numbers: Weight :  up to 150000 kg (330000 pounds) Length :  27-33 m (88-108 feet) depending on location (the largest live in Antarctic) Life :       unknown (maybe about 90 years) but sexually mature at 5-15 years. Diet :       Krill, a lot of it! 3.6 metric tons (4 imperial tons) of krill each day. However a picture (or in this case, a drawing) is much more effective in visualizing how large they are! (photo by Harry Wilson via I fucking love science ) They are considered endangered and it's estimated there are 5000-12000 Blue Whales r...

I haven't made a new post but it's like I did! I significantly updated the post about the flags of Haiti and Lichtenstein by adding other interesting examples of similar flags around the world! Have a look,  it's totally worth it!  Here is the link !  

There is place (and only one!) in the world, where a boat can sail under a train driving under a car driving under an airplane! It's the Boston University Bridge! Amazing! Location: Commonwealth Avenue, Boston, Massachussetts. River: Charles River ( image source http://en.structurae.de/ )   ( image source: http://www.bostonbyaida.com/ )

Today I learnt why cats do purr. In a nutshell: purring is a kind of self-medication. Probably. Let's see why. Cats purr not only when we stoke them but also in other moments in their life, as when they nurse their kittens or ... when they are in pain or near to death! These facts seem to tell us that purring has nothing to do with happiness, or with the pleasure to be with us... Cats purr by pulsing muscles in their larynx and diaphragm. The resulting vibrations have frequencies between 25 and 150 Hz.  Interestingly, scientific studies have shown that exposure to this frequency range can improve bone density and promote healing... hence the conclusion: purring is a kind of self-medication! This makes a lot of sense, since these adorable creatures are quite lazy (unlike dogs, cats do not like to chase balls) and nevertheless they stay healthy (even without physical exercise!) Amazing! References: http://www.scientificamerican.com/ SciShow Video

Thanks to the youtube, today I learnt that chicken heads have a very sofisticated gyroscopic system! Watch the cool videos below, it's some really amazing stuff! The same guy got also the idea to mount a camera on a chicken head, you know... to make a chicken powered steedycam... and here is the result! Sources: Youtube Channel: Smarter Every Day http://www.youtube.com/watch?v=_dPlkFPowCc http://www.youtube.com/watch?v=UytSNlHw8J8

Have you ever wondered how the months got their names? I did it and this is what I learnt. Crash course of calendar history ... To understand the origin, the etymology of these names, we have first to refer to Latin and to Roman culture. Indeed Latin names of months haven't changed since 8 AD! I will happily omit all changes, over the centuries, in the definition of months, I will consider only the names. If you want to know more, please check references. Let's start! In Latin,  the 12 Julian (and Gregorian ) months are: Ianuarius  Februarius  Martius Aprilis  Maius Iunis  Iulius (formerly  Quintilis ) Augustus (formerly  Sextilis ) September October  November December as you see, many of them sound quite familiar to their English, German or Italian versions! At the beginning,  there was the Ancient Roman calendar, introduced in 753 BC, according to tradition, by Romulus , the founder of ROME. It had only 30...

I just found out that the name "Lego" came from the Danish phrase leg go dt which means "play well." Good to know :)

Why some countries drive on the left and some others on the right? I have always lived in countries with the keep-right rule, and if you look at the map below you'll see how in the majority of the world the keep-right rules applies (from wikipedia )! Red: Drives on right Blue: Drives on left Accustomed to the keep-right rule, I have always found strange that some countries like UK, Ireland or Australia had the opposite convention. Well, as I learnt today, for some reasons it made and still makes more sense the keep-left rule. Let's see why. Everything started in the Middle Ages or probably even earlier in the Roman empire. In those times (and partially still today...) roads were very safe, so meeting people coming the other way was something best done defensively. Indeed, by keeping the left side of the road, you could more easily protect yourself, by drawing your weapon (attached to the left side), with your right hand. This is even more evident if you were r...

Here are some interestig facts about the Pentagon (Arlington, Virginia) the symbol of the US military. Thanks Wikipedia (references below). It is the world's largest office building by floor area, with about 6,500,000 sq ft (600,000 m 2 ), of which 3,700,000 sq ft (340,000 m 2 ) are used as offices . Approximately 28,000 military and civilian employees and about 3,000 non-defense support personnel work in the Pentagon. The site originally chosen was Arlington Farms which had a roughly pentagonal shape, so the building was planned accordingly as an irregular pentagon.  Concerned that the new building could obstruct the view of Washington, D.C. from Arlington Cemetery, President Roosevelt ended up selecting the Hoover Airport site instead. The building retained its pentagonal layout because a major redesign at that stage would have been costly, and Roosevelt liked the design. Freed of the constraints of the asymmetric Arlington Farms site, it was mo...

This is really interesting! Do you know that at birth we have about 300 bones but as adult this number decreases to 206?! This happens because many of our baby bones "fuse" together. One noticeable and well known example of this process is the human cranium. At birth, the cranium three unfused plates, allowing for passage of the baby's head through the birth canal (yes, your head was squeezed a bit!). Within 18-24 months, these plates fuse into one piece, closing the "fontanelles". References: http://science.howstuffworks.com/ http://www.bbc.co.uk/science/humanbody/body/factfiles/bonegrowth/ http://en.wikipedia.org/