the-french-artist/wikipedia_20220301.simple_sentence_split huggingface dataset:
This article is only about the chemistry of the alcohols.
The alcohol used in drinks is ethanol; more information can be found at alcoholic drink and alcoholism.
In chemistry, alcohol is a general term which refers to many organic compounds used in industry and science as reagents, solvents, and fuels.
Alcohols are carbohydrates which are  made of an alkyl group with one or more hydroxyl (-OH) groups bound to its carbon atoms.
Alcohol is colorless, and also transparent.
Names for alcohol
Common names often are made by taking the name of the alkyl group, and adding the word "alcohol".
For example, "methyl alcohol" or "ethyl alcohol".
IUPAC names are made by taking the name of the alkane chain, removing the last "e", and adding "ol".
Examples of this are "methanol" and "ethanol".
The hydroxyl (OH) group makes alcohols polar.
Alcohols are very weakly acidic.
Most alcohols are highly flammable.
Common alcohols
In common usage, "alcohol" often means ethanol or "grain alcohol". (
See also: alcoholic proof).
Isopropyl alcohol (sec-propyl alcohol, propan-2-ol, 2-propanol) H3C-CH(OH)-CH3, or "rubbing alcohol"
ethylene glycol (ethane-1,2-diol) HO-CH2-CH2-OH, which is the main substance in antifreeze
glycerin (or glycerol, propane-1,2,3-triol) HO-CH2-CH(OH)-CH2-OH bound in natural fats and oils, which are triglycerides (triacylglycerols)
phenol, an alcohol where the hydroxyl group is bound to a benzene ring.
Functional groups
Wolfgang Amadeus Mozart (January 27, 1756 – December 5, 1791; pronounced MOHT-sart) was an Austrian composer (music writer), instrumentalist, and music teacher.
His full baptised name was Johannes Chrysostomus Wolfgangus Theophillus Mozart.
He was born in Salzburg, Austria, the youngest child of Leopold and Anna Maria Mozart.
From a very early age, the young Mozart showed great musical talent.
He toured Europe with his parents and older sister "Nannerl" for several years performing for royalty and the aristocratic elite.
As a young man, Mozart tried but failed to establish himself as a composer in Paris.
He returned to Salzburg where he was briefly employed in the court of the Archbishop of Salzburg.
He was restless, aware of his genius, and thought Salzburg too small for his talent.
He relocated to Vienna where he met with some success.
He married Constance Weber and fathered two sons.
He died in Vienna after a brief but unknown illness.
Mozart wrote more than 600 musical works, all of the very highest quality.
His works include the operas The Marriage of Figaro, Don Giovanni, Così fan tutte and The Magic Flute; the symphonies in E-flat major, G minor, and C major ("Jupiter"); concertos for piano, violin, and various wind instruments; and numerous chamber pieces, works for the church, minuets and other dances, songs, and the Requiem.
Along with Bach and Beethoven, Mozart is regarded as one of the greatest composers who has ever lived.
Family and early years
Wolfgang Amadeus Mozart ("Wolfi" or Wolferl") was born in Salzburg, Austria, to Leopold and Anna Maria Mozart.
Leopold was a violinist in the orchestra of the archbishop of Salzburg and the author of a best-selling introduction to playing the violin.
Young Mozart showed evidence of great musical talent at a very early age.
He was playing the harpsichord and the violin at the age of five, and writing little pieces of music.
Mozart's sister Marianna ("Nannerl") was a talented youngster.
The two children received their musical and academic education from their father.
The family toured Europe for a few years, performing for royals and aristocrats.
Mozart performed in Munich, Prague, Paris, The Hague and London.
In London, he performed for King George III.
He met the composer Johann Christian Bach, one of the sons of Johann Sebastian Bach.
He sat on the knee of Johann Christian Bach (1735–1782) and improvised a fugue.
And here, at the age of eight, he heard his ﬁrst two symphonies performed.
Eventually, the Mozarts made their way back to Salzburg.
But in 1768, they were off again to Vienna, where the now twelve-year-old Wolfgang staged a production of his ﬁrst opera, Bastien und Bastienne.
And he was infected with smallpox at that time.
He recovered but his face was pock-marked for life.
He went to Italy where he heard music by many famous Italian composers, including Gregorio Allegri who had written a piece called Miserere.
This piece had been written for the Pope for the choir of the Vatican to sing.
No one was allowed to see the written music so that no other choir would be able to sing it.
Mozart heard the piece once and then wrote it all down from memory.
He met the Pope and was given a knighthood (Order of the Golden Spur).
In 1777, he went on a journey with his mother.
In Mannheim, he fell in love with Aloysia Weber.
She was 16 years old and studying singing.
Mozart wanted to take her to Italy to make her famous, but his father put a stop to these plans.
By 1778, Mozart and his mother were in Paris.
His mother died there.
Mozart wrote some small operas when he was young, but his first really important opera was Idomeneo.
It was first performed in Munich in 1780.
The next year he went to Vienna.
By this time he was working, like his father, for the Archbishop of Salzburg.
When he went back to Salzburg he argued with the Archbishop who actually kicked him out.
Mozart went off to Vienna where he would spend the rest of his life.
In 1782 he married Constanze Weber, one of the three younger sisters of Aloysia (who by now was married to someone else).
They were to have seven children, but five of them died in childhood.
Mozart’s father did not approve of the marriage.
Constanze was a loving wife, but, like Mozart, she was not good at looking after money, so they were often very poor.
In that same year, 1782, Mozart wrote another very successful opera: Die Entführung aus dem Serail ("The Abduction from the Seraglio").
One famous story tells that, after the emperor had heard the opera, he told Mozart that there were “too many notes”.
Mozart answered: “Just as many as are necessary, Your Majesty.”
Mozart started a series of concerts in which he played his own piano concertos, conducting from the keyboard.
He met the composer Joseph Haydn and the two men became great friends, often playing together in a string quartet.
Haydn said to Leopold Mozart one day: "Before God and as an honest man I tell you that your son is the greatest composer known to me either in person or by name.
He has taste, and what is more, the most profound knowledge of composition."
Mozart was in the same Masonic Lodge as Haydn, and he dedicated some of his string quartets to him.
The audiences in Vienna did not give Mozart much support after a few years, so he often went to Prague where the audiences loved him.
His opera The Marriage of Figaro was very popular, and in 1787 he gave the first performance there of his opera Don Giovanni.
Illness and death
There are several stories about Mozart’s last illness and death, and it is not easy to be sure what happened.
He was working on an opera The Magic Flute which is one of his best works and a very popular opera today.
It is written in German, not Italian, like most of his other operas.
In some ways it is like an English pantomime.
At the same time that he was working on this he was asked by a stranger to compose a requiem.
He was told to write this in secret.
Then he was asked to write an Italian opera La Clemenza di Tito, which was performed in Prague during September 1791.
At the end of September The Magic Flute was given its first performance.
Mozart then worked very hard at the Requiem.
He must have realized that he was already very ill, and that in a way the requiem (a mass for the dead) was for himself.
He died in Vienna before he could finish it.
Constanze asked another composer, a man called Franz Xaver Süssmayr, to finish the work.
Mozart was buried in the St. Marx Cemetery.
Mozart’s music
Mozart's music, like that of Haydn, is the very best of what is known as the Classical style.
At the time he started to compose, the Baroque period was just coming to an end.
Tastes were changing in music.
Form, balance and elegance were thought of as more important than counterpoint.
Mozart was the first great composer to write music for the piano, an instrument which had only just become popular.
He wrote almost every kind of music: symphonies, operas, solo concertos, chamber music, especially string quartets and string quintets, and the piano sonata.
He also wrote a lot of religious music, including masses, as well as popular music like dances, divertimenti and serenades.
When Mozart was young a symphony was usually a short, simple piece for entertainment.
Mozart made the symphony into a carefully worked-out piece lasting up to half an hour.
His last three symphonies are especially fine masterpieces.
His concertos, especially his piano concertos, are far more advanced than anything that had been written before.
Although Mozart behaved in truly childish ways at times, he was good at understanding human character.
This is clear in his operas, where he introduced many subtle effects to describe the characters in the story.
Mozart's operas are among his greatest works.
He understood people's characters very well and was able to write music which tells us everything about the personalities in the operas.
The three operas in which he set words by Lorenzo Da Ponte: Don Giovanni, Le Nozze di Figaro (The Marriage of Figaro) and Cosi fan tutte each include some very clever ensembles in which several characters are singing at once, each one showing his or her view of the situation.
As well as many great masterpieces, Mozart wrote many pieces in a more popular style, including some tunes that everybody knows today.
His serenade Eine kleine Nachtmusik K525 is known everywhere, as is the Turkish Rondo from his Piano Sonata in A K331, the opening of the Symphony No.
40 in G minor K550, and the birdcatcher’s song from The Magic Flute K620.
Regarding the instruments that Mozart was using for composing and performing, there was a number of them.
In his early years he got to know pianos made by Franz Jakob Späth from Regensburg.
Later in Augsburg Mozart got impressed by pianos from Stein.
After moving to Vienna the composer purchased an instrument by Walter.
Catalogue of works
Some time after Mozart’s death a man called Köchel studied all Mozart’s music, tried to put them in chronological order, and gave them a number.
The number helps us to know exactly which work is meant, for example Symphony in G minor K183 is not the same piece as Symphony in G minor K550 (K stands for Köchel.
Sometimes it is written "KV550" standing for "Köchel Verzeichnis" i.e. "Köchel Catalogue").
The highest Köchel number is 626, his requiem mass.
Amadeus (film)
Groves Dictionary of Music and Musicians, edited by Stanley Sadie; 1980;
Listening To Western Music, written by Craig Wright; ISBN 978-0-495-11627-1
The Mozart Project
Mozart livecams Live pictures of Mozart Birth house, Mozart Monument, Mozart lives on View and so on.
1756 births
1791 deaths
Austrian composers
Child prodigies
Classical era composers
People from Salzburg
Smallpox survivors
Austrian Roman Catholics
Johann Sebastian Bach (31 March 1685 in Eisenach – 28 July 1750 in Leipzig; pronounced BAHK) was a German composer and organist.
He lived in the last part of the Baroque period.
He is most famous for his work Toccata and Fugue in D Minor, St. Matthew Passion, St. John Passion, Mass in B minor, and the Brandenburg Concertos.
He spent several years working at courts of noblemen.
Here he wrote most of his chamber music and orchestral music.
Most of his life, however, he worked in a church where he was expected to write church music.
Bach wrote almost every kind of music except opera.
During the last part of his life most composers were writing in a new style called the Classical style, but Bach always wrote in the Baroque style.
That made some people at the time think he was old-fashioned, but today we know that his work is the very best of Baroque music.
Along with Mozart and Beethoven, Bach is regarded as one of the greatest composers who has ever lived.
Bach came from a highly musical family.
His father, Johann Ambrosius Bach, was a trumpeter at the court of Saxe-Eisenach.
Many of his relatives were professional musicians of some sort: violinists and town musicians, organists, Cantors (Directors of Music in a church), court musicians and Kapellmeisters (Directors of Music at a royal court).
Most of them played several instruments.
Of his twenty children, several became quite famous composers, especially Carl Philipp Emanuel Bach (1714–1788), Johann Christian Bach (1735–1782), Johann Christoph Friedrich Bach and Wilhelm Friedemann Bach (1710–1784).
When he was fifteen, he went to the small town of Lüneburg.
At first he sang treble in the choir and was said to have a very fine treble voice, but his voice very soon got lower, so he made himself useful playing instruments.
He learned by listening to famous organists like Reincken (1623–1722) and Dietrich Buxtehude (1637–1707).
Bach got his first job in 1703 in Arnstadt.
It was a well-paid job for a young boy who was 18 years old.
There was a new organ in the church, and Bach already knew a lot about organ building as well as being a brilliant organist.
They asked him to examine the new organ, and then they offered him a job.
Bach spent four years as organist there.
He composed some organ works.
Unfortunately, the congregation were not musical enough to like it.
They did not understand the ornamental notes he added to the hymn tunes.
Bach got rather fed up with the priests who were always complaining about it, so he resigned and took another job in Mühlhausen, not far away.
After a year there, he gave up that job and went to a big town called Weimar.
Weimar years (1708–1717)
Johann Sebastian was made organist to the Duke of Saxe-Weimar.
At the Duke’s court there was a chapel with an organ.
Bach composed many of his great organ works at this time.
He became very famous as an organist and was invited to play in other big churches and to give advice on organ building.
He was extremely good at improvisation.
On one occasion he was in Dresden at the same time as a French organist named Louis Marchant.
There was going to be a competition between the two men to see who was better at improvisation.
Bach was practicing the day before and Marchant heard him.
He realized that Bach would win, so he left.
In 1714 the Duke made Bach Konzertmeister (Concertmaster, a job that paid more money.)
He had to write cantatas for church services.
In 1717 he was offered a job in the town of Cöthen, where he would earn an even better salary.
The Duke was angry and did not want him to go but Bach insisted, so the Duke put Bach in prison for a month.
In the end he had to let the musician go.
Cöthen (1717–1723)
At Cöthen, Bach worked for Prince Leopold.
The Prince was very musical and a wonderful man to work for.
Bach was Kapellmeister (Director of Music) and was treated well.
The organ was not very good, and it was not used much, so Bach did not write any organ music during this period.
The Duke had an orchestra, and Bach was in charge.
Nearly all Bach’s orchestral works were written in Cöthen: the Brandenburg Concertos, the violin concertos, the orchestral suites, the solo music for violin and for cello, and a lot of keyboard music for harpsichord or clavichord.
During 1719, the great composer George Frideric Handel, who had moved to England, came to Germany to visit his mother.
Bach wanted to meet Handel, who was only 30 km away, but these two famous musicians never met.
Handel wanted to spend his limited time in Germany with his mother who was old and frail, knowing that it would be the last time he would see her.
Bach’s first wife, Maria Barbara Bach, died in 1720.
Soon afterwards, he married Anna Magdalena with whom he had another thirteen children.
However, several of his children died young.
Leipzig (1723–1750)
In 1723 Bach moved to Leipzig to take the job of Cantor at the St Thomas Church, a very large church in the town.
As Cantor he was in charge of all the music, both at St Thomas and at another church nearby.
He also had to compose music for the town.
It was an excellent job, and more secure than being at a court.
The schools were good for his sons.
Bach stayed in Leipzig until his death.
He loved his job most of the time and worked very hard.
He composed many cantatas for the church services.
These services were very long, lasting about three hours.
Many of the cantatas he wrote last about 30 minutes, and that was just one part of a service!
He had assistants to play the organ.
Bach himself directed the choir and the orchestra.
There were probably 16 singers in the choir and 18 players in the orchestra.
He wrote the St Matthew Passion and the St John Passion.
Both these works, which are very long, tell the story of Jesus dying on the cross.
They are among the most famous pieces of music ever written.
He also wrote cantatas for special occasions such as weddings or funerals.
Life was not always easy, and sometimes there were arguments with the people who ruled the church.
The sub-deacon wanted to choose some of the hymns, but this was the Cantor’s job.
Bach was a sensible man, and he managed to get his way without making enemies.
On another occasion he argued with the headmaster of the school (Bach had to do some teaching at the church school) about who was allowed to choose the choir section leaders.
This actually went to court, and Bach won the case.
Bach often made journeys to other towns.
In 1747 he visited the court of Prussian King Frederick the Great near Berlin.
The king, a music lover, gave Bach a theme to improvise from on the harpsichord.
Bach sat down and improvised a fugue using this theme.
Later Bach wrote a very long composition for flute, violin and harpsichord with cello accompaniment, in many movements, all based on this theme.
At the end, the theme is heard in 5 of the 6 voices.
Bach called it The Musical Offering and he sent it to the king.
Bach wrote many fugues, eventually he decided to write a collection called The Art of Fugue.
His plan was to publish it, but he died before he could finish it (his son later published it in his honor, as Bach's last published piece).
In the last year or two of his life, he became blind in spite of two eye operations.
The JS Bach Home Page-Part of joint Bach website project
J.S. Bach Archive and Bibliography-Part of joint Bach website project
The DigitalBach Project at the Oregon Bach Festival
1685 births
1750 deaths
Johann Sebastian
Baroque composers
German composers
German Lutherans
German organists
People from Saxony-Anhalt
The most important thing to remember about the Earth and other planets is that they do not come from the Sun.
They or their materials were picked up by the Sun's gravitation as it moved through space.
The Sun is just composed of hydrogen, with a little bit of helium.
The material which makes up planets and their satellites is almost entirely heavier elements whose origin was in earlier supernovae explosions.
The planets do give off small quantities of hydrogen and helium: this comes from the decay of larger radioactive molecules whose origin is also ancient supernovae.
A complicating factor is the Moon, which was formed by an impact of a large body with the early Earth.
This means the origin of life on the Earth would have taken place after the Moon was formed.
The atmosphere is the layer of gases around the Earth.
It is held in place by Earth's gravity.
It is today  made up mainly of nitrogen (78.1%).
It also has plentiful oxygen (20.9%) and small amounts of argon (0.9%), carbon dioxide (~ 0.035%), water vapor, and other gases.
The atmosphere protects life on Earth by absorbing (taking) ultraviolet rays from the sun.
It makes our days cooler and our nights warmer.
Solid particulates, including ash, dust, volcanic ash, etc.
are small parts of atmosphere.
They are important in making clouds and fog.
The atmosphere does not end at a specific place.
The higher above the Earth, the thinner the atmosphere.
There is no clear border between the atmosphere and outer space, though the Kármán line is sometimes treated as a border.
Even higher, for some purposes the edge of the magnetosphere is treated as a border.
75% of the atmosphere is within  of the Earth's surface.
History of Earth's atmosphere
The first atmosphere consisted of gases in the solar nebula, mainly hydrogen.
There might also have been simple hydrides such as those now found in the gas giants (Jupiter and Saturn): water vapor, methane and ammonia.
The atmosphere gradually changed to mostly carbon dioxide and nitrogen.
The lighter gases, like hydrogen and helium, cannot be held by the Earth's gravity, and would escape.
For a long time (say two billion years or more), the atmosphere was dominated by carbon dioxide.
In the Great Oxygenation Event the atmosphere changed to the kind we have now, with oxygen replacing the carbon dioxide.
Our atmosphere is still mostly nitrogen, but most living organisms interact more with oxygen than with nitrogen.
Oxygenation began with cyanobacteria making free oxygen by photosynthesis.
Most organisms today need oxygen for their respiration: only a few anaerobic organisms can grow without oxygen.
Temperature and the atmospheric layers
Some parts of the atmosphere are hot or cold, depending on height.
Starting from the surface and climbing straight up, the air gets colder in the troposphere, but then it becomes hotter, higher in the stratosphere.
These changes of temperature are divided into layers.
These are like layers of an onion.
The difference between the layers is the way the temperature changes.
Troposphere - Starts at the ground.
Ends somewhere between .
The higher, the colder.
Weather in this layer affects our daily life.
Stratosphere - Starts at .
Ends at .
The higher, the hotter.
The heat comes from the Ozone layer at the top of the stratosphere.
There is little water vapor and other substances in this layer.
Airplanes fly in this layer because it is usually stable and air resistance is small.
Mesosphere - Starts at .
Winds in this layer are strong, so the temperature is not stable.
Thermosphere - Starts at .
Ends at  or higher.
This layer is very important in radio communication because it helps to reflect some radio waves.
Exosphere - Above the thermosphere.
This is the top layer, and merges into interplanetary space.
Where one layer changes to the next have been named "-pauses."
So the tropopause is where the troposphere ends ( high).
The stratopause is at the end of the stratosphere.
The mesopause is at the end of the mesosphere.
The atmosphere has pressure.
This is because even though air is a gas, it has weight.
The average atmospheric pressure at sea level is about .
Density and mass
The density of air at sea level is about 1.2 kilograms per cubic meter.
This density becomes less at higher altitudes at the same rate that pressure becomes less.
The total mass of the atmosphere is about 5.1 × 1018 kg, which is only a very small part of the Earth's total mass.
The Atmosphere
The human penis is a male body part found on the outside of the body.
It is used for urination and for sexual reproduction.
The main sexual function of the penis is to be inserted into a female's vagina and deliver semen which may cause pregnancy.
This activity is called sexual intercourse.
There are many slang words for penis.
They include dick, cock, and schlong.
A euphemism for penis is male member.
The human penis exits the abdomen above the scrotum and hangs freely outside the body.
The main visible part is called the shaft.
The human penis has three parts.
Body of the penis: Main visible part of the penis.
The urethra runs underside of the penis.
Root of the penis: Invisible part of the penis.
It reaches near the anus and contains the bulb of penis and the crus of penis.
The crus of penis is attached to the pubic bone.
Skin of the penis: The shaft is covered by the skin.
The skin is not attached tightly to the inner tissue.
So it can move freely on the shaft.
The human penis is made up of three rod-shaped tissues.
It has two corpora cavernosa (special pieces of muscle) next to each other and a corpus spongiosum (spongy muscle) between them.
The end of the corpus spongiosum forms the glans penis.
The glans penis is covered by the foreskin in uncircumcised males.
The rounded base of the glans is called the corona.
The area on the bottom of the penis, where the foreskin is attached, is known as the frenulum of prepuce.
The urethra, the tube where urine and semen travel through, runs down the corpus spongiosum (spongy tissue), and opens at the tip of the penis.
The opening is called urinary meatus.
Sperm are made in the testes (ball-like organs) and stored in the epididymis (layer of tissue) around the testes.
During ejaculation, sperm are pushed up the vas deferens.
Fluids are added by the seminal vesicles, the prostate gland and the bulbourethral glands to make semen.
In sexual reproduction
A penis can become erect if a  male is sexually aroused (or sometimes during sleep, even though there is no sexual stimulation).
In an erection, the penis fills with blood.
The blood makes the penis become longer, thicker and harder.
Veins taking blood away from the penis get smaller, so less blood is taken through.
Arteries bringing blood to the penis get wider, bringing more blood to the penis.
Ejaculation is when semen is pushed from the penis.
It usually happens during an orgasm.
Males can ejaculate during sexual intercourse or by masturbation.
In reproductive sexual intercourse between a male and female, the erect penis is inserted into the vagina and moved in and out.
The vagina places pressure on the penis, which can cause the male to have an orgasm and ejaculate into the vagina, causing insemination.
Other forms of sex, like anal and oral sex, can also cause stimulation, and therefore orgasm and ejaculation.
In masturbation, a male can stimulate the penis and other sensitive areas of the body, such as the scrotum, by rubbing the genital area.
Ejaculation may also happen during sleep (called a 'wet dream').
A male must have started puberty before he can ejaculate.
During orgasm, muscles push semen from the penis.
Semen moves through the urethra and comes out of the hole at the tip of the penis.
Penis size in humans
The length and thickness of the penis is different for different people.
The size of a soft penis (not erect) is much smaller than when it is erect.
Some penises grow more when they get hard than other penises.
In most cases, whether a penis is big or small, it can still be used for sex.
It averages out to be around 3 to 6 inches long when not erect.
The average size of an erect human penis is between 13 – 16 cm (5.1– 6 in).
The average circumference of a penis is 12.3 cm (4.85 in) when fully erect.
The penis grows bigger during puberty.
At the start of puberty, the average length of the penis is .
The penis reaches adult size about 5 years later.
A study done in 1996 found the mean length of an adult man's penis is  when it is not erect.
The average length of an erect penis is about .
The foreskin is a fold of skin that covers the end of the penis.
Cutting off the foreskin is called circumcision.
The foreskin is connected to the head of the penis.
During circumcision, the foreskin is removed from the penis.
Circumcision is usually performed on infant males for medical, religious or cultural reasons like in the USA, Philippines and South Korea.
In Europe only Jews and Muslim men are circumcised of religious reason.
Uncommon by christian europe male.
Some males have the foreskin cut off when they are adults because they have problems with their foreskin.
Some males have the foreskin cut off because they want to change how their penis looks.
In common speech, you can say that someone is cut or uncut, meaning circumcised or not circumcised .
In some religions, babies and young boys have their foreskin cut off.
This is expected in Islam and Judaism.
It is not required according to Christianity.
In Judaism, infant males are required to have their foreskin removed as a sign of the covenant (ancient promise) made with God.
Skin color
A young boy's penis skin is the same color as his other skin.
Around age 12-15, a boy's penis skin gets slightly darker.
This is normal because of puberty.
This is caused by sex hormones (natural chemicals), especially testosterone.
Testosterone makes more melanin.
Melanin is the amino acid that causes skin color. (
Sunlight also makes more melanin so skin gets a sun tan.)
Usually a teenager or man's penis side skin is slightly darker than other skin on his body.
The tip (glans) of the penis is usually pink or red color even if the penis side skin is dark.
If the man is not circumcised, the tip is usually covered by the foreskin.
The foreskin is about the same color as the skin on the side of the penis.
If a man's penis skin changes color and he doesn't know why, he should go to a doctor.
He could have an infection, diabetes or cancer.
A sunburn on the penis can happen quickly.
If a man is outside without clothes, he will get a sun tan.
That is normal.
Too much sun causes a sunburn.
Doctors say to use sunscreen (sun cream) before and after nude swimming.
A sunburn can happen in a few minutes on a very sunny day.
Since the oldest cultures the penis has assumed a strong importance as a symbol of fertility used also in religious ceremonies to propitiate the reproductive capacity of men and beasts.
For example, in Roman paganism the god Priapus is characterized by a huge penis.
Kinsey Institute on the penis
Anatomy of the male reproductive system
The Sahara, in North Africa, is the largest desert in the world except for Antarctica.
The Sahara is the largest hot desert.
It is bounded by the Atlantic Ocean, the Atlas Mountains, the Mediterranean Sea, the Red Sea, and the Sahel region.
It runs through many countries including Morocco, Algeria, Tunisia, Libya, Egypt, Mauritania, Mali, Niger, Chad, and The Sudan.
Most parts are uninhabited, but some people manage to survive in places where there is water.
The Sahara Desert is about 9,000,000 square kilometers (3.5 million square miles) in size.
It has been both larger and smaller at different times.
After the last ice age it became more fertile, then dried up again.
It is the hottest place on the Earth, but not the driest.
The driest is the Atacama Desert in South America.
The Sahara has about the same size as the whole United States.
The Sahara has one of the world's most harsh climates.
Typically, the Sahara landscape experiences little rainfall, powerful winds and wide temperature ranges.
In some areas, there can be no rainfall for up to years at a time.
In the summer, daytime air temperatures across the Sahara often reach over 100 degrees Fahrenheit.
In the winter, freezing temperatures may occur in the northern Sahara, and milder temperatures, across the southern Sahara.
Snow may fall occasionally in some of the higher mountain ranges and rarely, on the desert floor.
The highest mountain is 3415 m, and is the Emi Koussi in Chad.
Some mountain peaks in the Sahara Desert have snow even in the summer.
The main mountain ranges is the Atlas Mountains in Algeria.
The Sahara's lowest point lies in the Qattara Depression in Egypt, at about 130 metres below sea level.
Sand sheets and dunes are about 25% of the Sahara.
The other parts are mountains, steppes with a lot of stones, and oases.
Several rivers run through the Sahara.
However, most of them come and go through the seasons, except for the Nile River and Niger River.
Metallic minerals are very important to most Saharan countries.
Algeria and Mauritania have several major deposits of iron ore.
There are also uranium mines, mostly in Niger.
A lot of phosphates are in Morocco and Western Sahara.
Petroleum is mainly found in Algeria, where it is very important to the economy.
While mineral exploitation has led to economic growth in Sahara, this has rarely helped the indigenous population, as skilled workers have been brought from other countries.
Of the Sahara's around 4 million people, most live in Mauritania, Western Sahara, Algeria, Libya and Egypt.
Dominant groups of people are Sahrawis and Tuareg people.
The largest city is Nouakchott, Mauritania's capital.
Other important cities are Tamanrasset in Algeria, and Sebha and Ghat in Libya.
Only 200,000 km² of the Sahara are fertile oases, where dates, corn, and fruits are grown.
The few fertile regions today are fed by underground rivers and underground basins.
Many of Sahara's oases rests in depressions (areas under sea level) allowing water to surface from underground reservoirs; artesian wells.
The soil in Sahara is low in organic matter.
The soil in depressions is often saline.
Other sorts of vegetation include scattered concentrations of grasses, shrubs and trees in the highlands, as well as in the oases and along river beds.
Some plants are well adjusted to the climate, allowing them to germinate within 3 days of rain and sow their seeds within 2 weeks after that.
Animals living in the Sahara include gerbil, jerboa, cape hare and desert hedgehog, barbary sheep, oryx, gazelle, deer, wild ass, baboon, hyena, jackal, sand fox, weasel and mongoose.
The bird life counts more than 300 species.
Reptiles, including 4 species of snake also live here.
The most venomous scorpion in the world lives here.
4,000 years ago, the Sahara was a thriving savanna grassland with a great variety of wildlife.
This included animals such as elephants and giraffes.
Climate change has caused the rainfall to be less and turn the Sahara into the barren, desert wilderness as we know it today.
Flora and fauna of the Sahara
Paris (nicknamed the "City of light") is the capital city of France, and the largest city in France.
The area is , and around 2.15 million people live there.
If suburbs are counted, the population of the Paris area rises to 10.7 million people.
It is the most densely populated city in the European Union, with  20.653 people per square kilometer.
The Seine river runs through the oldest part of Paris, and divides it into two parts, known as the Left Bank and the Right Bank.
It is surrounded by many forests.
Paris is also the center of French economy, politics, traffic and culture.
Paris has many art museums and historical buildings.
As a traffic center, Paris has a very good underground subway system (called the Metro).
It also has two airports.
The Metro was built in 1900, and its total length is more than .
The city has a multi-cultural style, because 19% of the people there are from outside France.
There are many different restaurants with all kinds of food.
Paris also has some types of pollution like air pollution and light pollution.
Julius Caesar conquered the Celtic "Parisii" tribe in 51 BC.
The Romans called the place Lutetia of the Parisii, or "Lutetia Parisiorum".
The place got a shorter name, "Paris", in 212 AD.
As the Roman Empire began to fall apart in the West, the Germanic tribe called the Franks moved in, taking it in 464.
In 506, their king Clovis I made it his capital.
Charlemagne moved his capital to Aachen in Germany, but Paris continued as an important town and was attacked by the Vikings twice.
When Hugh Capet became king of France in 987, he again made Paris his capital.
For a long time, the kings only controlled Paris and the surrounding area, as much of the rest of France was in the hands of barons or English.
During the Hundred Years' War, the English controlled Paris from 1420 to 1437.
During the Protestant Reformation, a huge massacre of French Protestants started there in 1572, called the Saint Bartholomew Day Massacre.
Paris saw many other troubles over the years of the "Ancien Régime" (Old Kingdom), then in 1789, the French Revolution began in Paris, leading to more massacres.
Paris was the Capital of the French Empire which, as well as France, covered Spain, Belgium, Holland, Luxembourg, Switzerland, Italy, most of Germany and some of Austria, Croatia, Slovenia and Poland.
The Empire ruled by Napoleon was from 1804-1814/1815.
The Russian army seized Paris from Napoleon in 1814, and the Prussian army captured it in 1871.
The next time it was captured was by the Nazi Germans in 1940.
The Allies freed the city in 1944 and it has not since been captured.
Paris has an oceanic climate in the Köppen climate classification.
It has warm summers and cold winters, and rainfall year-round.
Paris has much to offer for sightseeing.
Here are five very famous examples:
The Eiffel Tower is the most famous sight in Paris, built by Gustave Eiffel in 1889 with  of iron — that means 18,000 pieces of iron and 2.5 million rivets.
With a height of 300 meters, for a long time it was the highest tower in the world.
Over 6 million people visit it every year.
There are three levels that you can visit, and the highest one is 2nd above the ground.
It was made for a fair, but the French government wanted to tear it down.
With rising popularity, it stayed.
The Louvre is a museum with very famous, old works of art, such as the Mona Lisa and the Venus de Milo.
The building was built as a house for French kings.
The Louvre is the third biggest museum in the world, with  of show room.
It is the most visited art museum in the world with over 5 million people visit it each year.
The Musée d'Orsay was a train station, but it is now an art museum.
Most of the art at the Musée D'Orsay was made between 1848 and 1915.
This is newer than the art at the Louvre.
The Moulin Rouge is a cabaret with many shows, and it opened in 1889.
It is in Montmartre — a part of Paris with an exciting nightlife.
In the Moulin Rouge, women put on a famous dance called the French cancan.
The Champs-Élysées is probably the most famous street in Paris, and one of the most famous in the world.
It is full of places to shop and eat.
On one end of the Champs-Élysées is the Arc de Triomphe.
The Notre Dame de Paris is a major Gothic cathedral, which was destroyed in 15 April 2019.
It is in "Île de la Cité".
The Basilica of Sacré-Coeur is a major church devoted to the Sacred Heart.
Because the city of Paris is roughly only 6 miles across, visitors have a wide range of options when it comes to transportation.
While much of the more well-known attractions are in the center of the city and are best experienced by walking, there are many destinations that require other means of transport.
While taxis offer a fast and relatively inexpensive means of travel, Paris’ public transportation system offers an enjoyable, stress-free way to explore the city.
The Paris Métro system was built in 1900 by engineer Fulgence Bienvenüe and architect Hector Guimard.
The Métro covers over 124 miles with 300 stations and 16 lines.
Servicing over 6 million residents and tourists every day, the Métro was designed to be an efficient and reliable alternative to the congestion of traffic.
Every building in Paris is less than 500 meters from a train station, so accessibility is never a problem.
The 16 Métro lines are identified by their final destinations.
A rider can simply select the appropriate line and take it in the direction s/he wants.
The Métro stations are well marked, and there are ticket booths at most entrances.
1900 – The 2nd Summer Olympic Games took place in Paris.
1924 – The 8th Summer Olympic Games took place in Paris.
1998 – The FIFA World Cup
2024 – The 33rd Summer Olympic Games will take place in Paris.
Official website of the Paris Convention and Visitors Bureau (English version)
This city at the Historical Association for Joan of Arc Studies
Visiting Paris – tips and useful advice
RATP
Navigating the Paris Métro
The Holocaust, sometimes called The Shoah (), was a genocide in which Nazi Germany systematically killed people during World War II.
About six million Jews were killed, as well as five million others that the Nazis claimed were inferior (mostly Slavs, communists, Romani/Roma people, people with disabilities, homosexuals, and Jehovah's Witnesses).
These people were rounded up, put in ghettos, forced to work in concentration camps, and then killed in gas chambers.
Jews were forced to wear the yellow Star of David, a symbol of their religion.
Why were the Jews killed?
There was hatred and persecution of Jews (anti-Semitism) in Europe for hundreds of years.
Many people wrongly thought that all Jews became rich by stealing money from other people, such as Christians; that they did not like people other than their fellow Jews; and that they harmed children to use their blood for religious rituals (blood libel).
These beliefs were not true, and were based on stereotypes and prejudices.
Adolf Hitler was born in Austria during this time, when many people disliked Jews.
He may have been jealous of Jewish success in Austria.
However, in a book he wrote called Mein Kampf ("My Struggle"), he said it was the Jews' fault that Germany and Austria lost World War I. He also wrote that Germany's economic problems were the Jews' fault.
Many people agreed with Hitler’s ideas and supported him as the leader of the Nazi Party.
Not all deaths were written down, so the exact numbers are unknown.
However, various sources approximate:
Jews (5.1–6 million killed), including:
Polish Jews (3 million killed);
Ethnic Poles (1.8-2 million killed);
Romani/Roma people (200,000–800,000 killed);
Disabled people (200,000–250,000 killed);
Homosexuals (22,000–25,000 killed);
Jehovah's Witnesses (950–2500 killed).
Led by Hitler, the Nazis killed millions of Jews.
They forced Jews to wear the golden Star of David on their upper bodies.
Jews were rounded up by the thousands and crammed into trains that took them to concentration camps like Auschwitz as well as death camps.
Most of the Jews killed in the Holocaust were not German.
They were from Poland or the Soviet Union.
The Nazis killed millions of people, hundreds at a time, with poison gas in special rooms called gas chambers.
They forced others to dig giant holes in the ground where, after days of hard work, Jews and other prisoners were shot, buried, and burned in a mass grave.
The Nazis executed many others by shooting, stabbing, or beating them to death.
Still, others died in forced marches from one camp to another.
Many other people died of starvation, diseases, and freezing to death because of the terrible conditions in the concentration camps.
On the other hand, there were people who saved Jews from the Holocaust, because they thought it was the right thing to do.
Some of them were later given "Righteous Among the Nations" awards by Yad Vashem.
Some people say the Holocaust did not happen at all, or was not as bad as historians say it was.
This is called Holocaust denial.
However, almost all historians agree that the Holocaust did happen and has been described correctly.
Many Holocaust deniers profess that the Nazis did not kill as many people as historians say.
Instead, they claim many of these people died from disease or lack of food, usually in order to shift blame from the Nazis.
These ideas have been disproven by historical accounts, eyewitness evidence, and documentary evidence from the Nazis themselves.
Also, many Jews were killed because Hitler ordered it.
In some countries in Europe, including Germany, it is against the law to say that the Holocaust never happened.
The Holocaust Martyrs' and Heroes' Remembrance Authority
United States Holocaust Memorial Museum
Kyoto () is a city in Japan.
This city was the capital of Japan from 794 until 1868.
Kyoto is a major city in the Kansai region of Japan.
Its population is 1.5 million people.
The city of Kyoto is the capital city of the prefecture of Kyoto.
Kyoto is one of the cultural, educational, and technology centers of Japan.
In it are many universities including Kyoto University, the second oldest national university of Japan.
In 1868, the city was called Saikyō ("Western capital") in order to distinguish it from Edo (Tokyo) which was the "Eastern capital".
There are mountains around the city on the east, north, and west sides.
Some people in Kyoto believe that these mountains make Kyoto's summer especially hot and humid, and Kyoto's winter very cold.
We can see many temples and shrines built in traditional Japanese architectural styles here.
Some of those buildings are registered as UNESCO World Heritage Sites.
On the other hand, since Kyoto was one of biggest and richest Japanese cities in the middle of the 19th century; the citizens were eager to import European style, and there are many European style buildings in the center of Kyoto for company offices and schools.
Kyoto is one of oldest cities in Japan.
Many tourists from all over the world come to Kyoto.
Japanese people often come to Kyoto in the spring to see the cherry blossoms, and in the autumn to see the leaves change color.
Traditional Kyoto food often uses vegetables.
McDonald's signboards in Kyoto are brown to preserve the traditional surroundings.
Former capitals of Japan
Anarchy (From Greek αναρχια meaning "without a leader") is a word that has more than one meaning.
Some of its meanings are:
When there is no leader, or when nobody has power over everyone (used just in the anarchist movement).
When there is no political order, and there is confusion (used often from mass media)
When people do not have any reason to work together, or do not have anything that makes them feel like a group.
In the first meaning listed, an anarchy might be a made-up or real society based on a group's beliefs about anarchism (see anarcho-communism).
In the second meaning listed, "anarchy" has to do with having no political order.
The CIA World factbook  says that there is only one nation, Somalia, that is in a state of anarchy.
In Somalia, the government is no longer in control, and some parts of the country are ruled by mobs and warlords who sometimes fight one another.
There are some countries (Afghanistan, Albania, Burundi, Bosnia and Herzegovina, and Rwanda) where government is "emerging" or "transitional", and were in civil unrest in the near past.
The DC  says that the Solomon Islands is moving towards civil unrest because "violence, corruption and crime have undermined stability and civil society".
When there is no political order, more than one government or political authority might sometimes compete for the same food, oil, land, or groups of people.
The word "Anarchy" to used to describe this.
However, because there is more than one competing authority, a better word might be polyarchy.
The difference between "anarchy" and "polyarchy" is important to someone who thinks that true anarchy would work well.
The word for someone who thinks this is "anarchist", and the word for this kind of thinking is "anarchism".
Anarchism has been thought about for hundreds of years.
The book called "The Politics of Individualism" attempts to teach its readers that anarchism is not always simply an opposition to the government, but a complicated political movement against the domination of few people.
Other uses of the word
(Another use of the word “Anarchy” is when it is said as “The Anarchy”.
This is the name that is sometimes given to the civil war and unsettled government in England when Stephen of England was King.)
Economic systems
DNA, short for deoxyribonucleic acid, is the molecule that contains the genetic code of organisms.
This includes animals, plants, protists, archaea and bacteria.
DNA is in each cell in the organism and tells cells what proteins to make.
Mostly, these proteins are enzymes.
DNA is inherited by children from their parents.
This is why children share traits with their parents, such as skin, hair and eye color.
The DNA in a person is a combination of the DNA from each of their parents.
Part of an organism's DNA is "non-coding DNA" sequences.
They do not code for protein sequences.
Some noncoding DNA is transcribed into non-coding RNA molecules, such as transfer RNA, ribosomal RNA, and regulatory RNAs.
Other sequences are not transcribed at all, or give rise to RNA of unknown function.
The amount of non-coding DNA varies greatly among species.
For example, over 98% of the human genome is non-coding DNA, while only about 2% of a typical bacterial genome is non-coding DNA.
Viruses use either DNA or RNA to infect organisms.
The genome replication of most DNA viruses takes place in the cell's nucleus, whereas RNA viruses usually replicate in the cytoplasm.
Structure of DNA
DNA has a double helix shape, which is like a ladder twisted into a spiral.
Each step of the ladder is a pair of nucleotides.
Nucleotides
deoxyribose, a kind of sugar with 5 carbon atoms,
a phosphate group made of phosphorus and oxygen, and
nitrogenous base
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)