Aarushhh/wikipedia-simple-splitted huggingface dataset:
A right angle is an angle with a measurement of 90 degrees. When two lines cross each other so that all the angles have the same size, the result is four right angles. The top of the letter T is at right angles to the vertical line. Walls of buildings are usually at right angles to the floor. Two things that are at right angles are called "perpendicular" or "orthogonal". This is expressed using the  symbol (such as in ).

Planes (flat surfaces) can also meet at right angles.  In a building, a wall and a floor are said to be perpendicular to each other, and they have a right angle. It also can be called a square angle.

Related pages
 Acute angle
 Obtuse angle
 Parallel (geometry)

References 

Angles
A reward is getting something good for doing a given task.  It needs someone who has the power to give the good thing. It is the opposite of punishment.

Ideas like risk and reward, reward and punishment are based on the idea that people do things, or avoid doing things, to get rewards. In psychology there is another idea that this is not true. This other idea says that training (conditioning) and emotions (affective factors) are much more important than the rewards or punishments given by others.

In trying to catch criminals and other bad people, the government often offers money to people. This money is given to people who may capture the criminal, or give information that helps the police catch them. For example, after the Eureka Stockade rebellion in Ballarat, Victoria in 1854, the government offered a big reward of 400 pounds for the capture of the people who had started it.
In 2001, the US government offered a big reward of 2.5 million dollars for help in capturing the person who had sent anthrax in letters to a newspaper journalist and 2 senators. Anthrax is a disease which can kill people.

Related pages
 Carrot and Stick

References

Basic English 850 words
A ranch is a farm for raising cows, horses, sheep or other livestock. Most ranches are large, but they can be any size. The word ranch is from the Spanish word "rancho". It is used in American and Canadian English. People who use a ranch are called ranchers.

A ranch may be on private or public land. The desert areas of the western United States have many ranches, because there is much land that is not very good for crops. There are also many in desert areas of Australia, where they are called stations. Someone who takes care of the livestock may be called a stockman or cowboy.

Related pages
Agriculture
A sport utility vehicle (SUV) is a type of vehicle. It is built as a rugged vehicle for cargo and passenger carrying. Originally SUVs were not designed to be fuel efficient but modern designs are getting better fuel mileage. In 2014 US sales of SUVs were over five million vehicles.

Appearance 
 

The typical SUV is a two-box design. Unlike a pickup truck (US term) that has an open cargo box the SUV has an enclosed cargo/passenger compartment. It has upright seating for five to seven passengers. It has an open interior with no trunk. It is often built on a pickup truck chassis for towing capacity, and usually has four wheel drive. Only about 15% of SUV owners ever go off-road. According to Jeep Wrangler brand manager Kevin Metz, 60% of Jeep Wrangler owners go off-road while around 80% of Rubicon owners do.
A similar class of vehicle is the crossover SUV,  a common Northern American term. That is built on a car chassis. Often it uses a Unibody chassis instead of the heavier body-on-frame design of SUVs. Crossover vehicles often have all-wheel-drive instead of four-wheel drive. Crossovers are usually lighter than SUVs and get better fuel mileage. In general, when referring to an SUV, many include crossovers. However it is incorrect to refer to an SUV on a truck frame as a crossover.

History 
  

Early SUVs were built like light commercial and light wheeled military utility vehicles. Famous examples were the World War Jeep (US), and the Land Rover (UK).
Off-roading sports 
   
Many kinds of off-roading in the USA are centered around SUVs. 
 Rockcrawling is a popular off-road sport. Vehicles used for rock crawling are usually modified with different tires, suspension and gear ratios. Rock crawling takes time to learn and can be very expensive. Most rock crawlers have full-time jobs and many get sponsors to help with the costs. The object is to get the vehicle across difficult to near-impossible rocks and terrain without completely destroying the vehicle.
The Camel Trophy competition (1981–2000) was an annual 4x4 competition. The first Camel trophy was held on the Trans-Amazonian Highway, a  road across Brazil. Over the next eight years, the expeditions crossed Sumatra, Papua New Guinea, Zaire, Brazil, Borneo, Australia, Madagascar and Sulawesi before returning to the Amazon. After the first year the endurance event came to be dominated by specially equipped Land Rover vehicles. The Camel Trophy Owners Club is a group of people who collect ex-Camel Trophy vehicles.   
 Jeep Jamborees have been held since 1953. Jeep Jamborees are off-road excursions that travel historic and scenic trails across the US. In 2013 alone there were 32 events in various locations. All models of Jeep enter the events and drivers range from first time off-roaders to seasoned veterans.
Easter Jeep Safari is an annual event held at Moab, Utah. It has been held every year since 1967. It runs for nine days ending on Easter Sunday and can have up to 1,000 vehicles of all kinds; not just Jeeps. It uses up to 40 trails in the Moab area. Trails are rated from easy to difficult.
 King of the Hammers is a one-day 200+ mile endurance off-road race. It combines desert racing and rock crawling. This race is held in February on Means Dry Lake at Johnson Valley, California USA. 2015 will be the 9th annual King of the Hammers event. The vehicles are extremely modified and for off-road use only.
Popularity 
There are many reasons why SUVs have become popular. One reason is the comfort of their large cabins. Many models can carry almost as much as a minivan. Another reason is the driver sits higher than other cars, giving better all-round vision. SUVs with truck frames are heavier (sometimes much heavier) than standard cars. Their size gives them an image of safety.

Men aren't the only targets of SUV and CUV ads. For example, some ads for the Subaru Forester are deliberately aimed at women buyers. Roughly 35 to 40 percent of SUV buyers are women. Ads commonly show SUVs driving across boulders or perched on a mountain peak. Advertisers know that one important reason many people buy SUVs is image.
Practicality for larger families is a consideration. Not only can the vehicle take a family of five or six, plus luggage, but also the family dog (who often has a special compartment at the back). On the other hand, the vehicle doesn't fit standard parking spaces. That can be quite a problem in, for example, the UK. The alternative, when groups of more than four travel, is to take more than one standard size car.

Other names 
In Australia and Europe SUVs are often called 4 wheel drives (4X4) or 4WDs.

References
Substance is the material, or matter, of which something is made. Substances are physical things that can be seen, touched, or measured. They are made up of one or more elemental parts. Iron, aluminium, water and air are examples of substances.

Problems of definition

The main problem of a clear definition of what the substance is that if, for example, to consider not just the universe (cosmos), being and non-being, and in general all, the question arises, what is the constant basic principle (attribute) is the basis of the substance, which generally consists of all (that is, matter, mind, senses, space, soul, and so on).

History of the concept

The Latin word substantia - a translation of the Greek word for the essence (ousia), and in Latin to describe the essence of using the word essentia. In ancient philosophy substance is treated as a substrate, the first principle of all things (for example, "water" of Thales, the "fire" of Heraclitus).
In modern times, the concept of substance is treated and spread widely. The first view is connected with an ontological understanding of substance as ultimate bases being (Francis Bacon, Benedict Spinoza, Gottfried Wilhelm Leibniz). Central category of metaphysics in philosophy substance is identified as with God and with nature and determined as the cause of itself (Latin, causa sui). The main characteristics (attributes) of a substance from Benedict Spinoza are thinking and stretch. By analogy with the philosophy of Benedict Spinoza substance considered in the light of the concept of René Descartes and Leibniz. The first substance is a unity of subject and object, and the second - the same atoms are simple beings who lose their stretch, but receive attribute aspirations (French, appetition) and multiplicity. Thanks Leibniz substance begins to associate with matter.
The second point of view on the substance - an epistemological understanding of the concept, its capabilities and the need for scientific knowledge (John Locke, David Hume). Immanuel Kant believed that the law under which any change in the substance of events and the number of stored it in nature remains the same, can be attributed to the "analogies of experience." Georg Wilhelm Friedrich Hegel defined substance as the integrity of changing, transient side of things, as a "major step in the development of the will." For Arthur Schopenhauer substance - matter for David Hume - a fiction, the coexistence properties.

Related articles 
 Chemical substance

Basic English 850 words
Physics
A symbol is a drawing, shape, or object that represents an idea, object, or amount of something.  

The most common symbols are letters, which are symbols of words and sounds. A symbol can be an actual object (such as the cross, a symbol of Christianity or a scepter, a symbol of royalty and power), or a certain color or pattern. Symbols are used often in poetry and other types of literature, sometimes as metaphors or similes.

A national emblem is a symbol for a certain country.

List of common symbols

There are thousands of symbols that are recognized by most people all over the world, and many more that are limited to certain regions, religions, sciences, etc..  Some of the best known ones are listed below.
Alpenhorn -> Switzerland
Asiatic Lion -> India
Balance (scale) -> justice
Bat -> vampire (western), luck (Chinese)
Bear -> the U.S. state of California
Beaver -> Canada
Boomerang -> Australia
Caduceus -> Medical profession
Cadillac -> top of the line (in USA only)
Cedar tree-> Lebanon
Cheetah -> speed
Cherry Blossom -> Japan
Chukar -> Pakistan
Compass rose -> navigation
Cowboys and Indians -> the old Western USA
Crucifix -> Christianity
Cupid, heart -> love
Cedrus deodara -> Pakistan
Donkey -> United States Democratic Party
Dove -> Peace
Dragon -> China / Wales
Eagle -> USA
Elephant -> United States Republican Party
Elephant -> Thailand
Fatima Jinnah -> Pakistan
Flags -> the associated countries
Fleur-de-lis -> scouts, the Canadian city of Quebec
Geneva cross -> ambulance, neutrality, humanitarian
Great Wall of China -> China
Hammer and sickle -> U.S.S.R., Communism
Hat and wand -> magic
Horseshoe -> good luck
Igloo -> North Pole
James Dean -> rebellion
Jasmine -> Pakistan
Kangaroo -> Australia
Kiwi -> New Zealand
Liberty Bell -> USA
Lightbulb -> idea
Lightning bolt -> electricity, speed
Lion -> England
Llama -> South America
Lotus -> Hinduism and Buddhism
Mango -> Pakistan
Markhor -> Pakistan
Maple leaf -> Canada
Mortar and pestle -> Pharmacy
Mount Fuji -> Japan
Mount Rushmore -> USA
Muhammad Ali Jinnah -> Pakistan
Owl -> wisdom/education (western worlds), may mean evil in other place.
Panda -> China
Peace symbol -> hippies
Penguin -> South Pole, Linux
Pine tree and crane -> long life (Chinese)
Plum flower -> China
Pocket protector -> nerds
Poinsettia -> Christmas
Polar bear -> North Pole 
Rainbow -> Peace, Disarmament, Sustainability
Rose -> England
Rams -> Guangzhou
Rolls Royce -> luxury, top of the line
Royal Bengal Tiger -> Bangladesh
St. Bernard (dog) -> rescue
Shamrock -> Ireland, Trinity
Shogun -> Japan
Skull and crossbones -> poison, danger
Star and crescent -> Islam
Star of David -> Judaism
Statue of Liberty -> USA
Swastika -> Hinduism, Buddhism, Nazism
Teen Talwar -> Pakistan
Thistle -> Scotland
Tulips -> Netherlands
Turkey -> Thanksgiving holiday
Uncle Sam -> USA
Unicorn -> good luck
Volvo cars -> bad/elderly drivers (Australia), prestige (European Union), Sweden
Water Lilly -> Bangladesh
White Flag -> France
Windmills -> Netherlands
Yin yang symbol -> Daoism
Related pages 
Semiotics
Symbolism
September (Sep.) is the ninth month of the year in the Gregorian calendar, coming between August and October. It has 30 days. Its name comes from the Latin word sept for "seven" (it was the seventh month of the year, before January and February were added to the beginning of the year.)

September always begins on the same day of the week as December, but never ends on the same day of the week as any other month.

The Month 

In the old Roman calendar, September was the seventh month, which is where it got its name ("Septem" means "seventh"). The ninth month at the time was November ("Novem" means "ninth"). With Julius Caesar's calendar reform, September became the ninth month, with 30 days. September comes after August and before October.

September begins on the same day of the week as December every year, as each other's first days are 13 weeks (91 days) apart. No other month of any year ends on the same day of the week as September; this month and May are the only two months with this property.
In common years, September starts on the same day of the week as April and July of the previous year, and in leap years, October of the previous year. In common years, September finishes on the same day of the week as April and December of the previous year, and in leap years, July of the previous year. In leap years and years immediately after that, September starts on the same day of the week as January of the previous year.

In years immediately before common years, September starts on the same day of the week as June of the following year, and in years immediately before leap years, March and November of the following year. In years immediately before common years, September finishes on the same day of the week as March and June of the following year, and in years immediately before leap years, August and November of the following year.
September is one of two months to have an equinox (the other is March, its seasonal equivalent in both hemispheres), where both day and night are roughly of equal length, occurring either on the 22nd or 23rd, halfway between the June and December solstices. In the Northern Hemisphere, Autumn (Fall) begins in this month, while in the Southern Hemisphere, this is the beginning of Spring. For meteorologists, the people who study the weather, these seasons begin on September 1 in those hemispheres. In most Northern Hemisphere countries, school starts in this month, following the summer holidays.

In Ancient Greece, September was called Boedromion. The Anglo-Saxons called it Gerstmonath, meaning "Barley month", referring to the harvest. In other countries, it is referred to as Autumn Month, such as in Finland (Syyskuu) and German-speaking parts of Switzerland (Herbstmonat).

Ethiopian New Year occurs in September. Jewish New Year also often occurs in this month.

Events and Occurrences

Fixed Events
September 1  Independence Day (Uzbekistan)
 September 1  Armed Struggle for Independence (Eritrea)
 September 1  Constitution Day (Slovakia)
 September 2  Independence Day (Vietnam)
 September 3  National Day of San Marino
 September 3  Independence Day (Qatar)
 September 3  Flag Day (Australia)
 September 3  Levy Mwanawasa Day (Zambia)
 September 3  Merchant Navy Day (United Kingdom)
 September 5  Teacher's Day (India)
 September 6  Independence Day (Swaziland)
 September 6  Unification Day (Bulgaria)
 September 7  Independence Day (Brazil)
 September 7  National Threatened Species Day (Australia)
 September 7  Victory Day (Mozambique)
 September 8  National Day of Andorra
 September 8  Independence Day (Republic of Macedonia)
 September 8  Nativity of the Blessed Virgin (feast day in Christianity)
 September 9  Admission Day (California)
 September 9  National Day of North Korea
 September 9  Independence Day (Tajikistan)
 September 11  National Day of Catalonia
 September 11  Patriot Day (United States)
September 11/12  Ethiopian New Year
 September 12  National Day of Cape Verde
 September 13  World Chocolate Day
 September 14  Exaltation of the Holy Cross (Roman Catholicism)
 September 15  Battle of Britain Day (United Kingdom)
 September 15  National Day of Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua
 September 16  Independence Day (Mexico)
 September 16  Independence Day (Papua New Guinea)
 September 16  Malaysia Day
 September 17  Constitution Day (United States)
 September 18  Independence Day (Chile)
 September 19  Armed Forces Day (Chile)
 September 19  Independence Day (Saint Kitts and Nevis)
 September 19  International Talk Like a Pirate Day
 September 21  Independence Day (Malta)
 September 21  Independence Day (Belize)
 September 21  World Freedom Day/International Peace Day
 September 21  World Alzheimer's Day, raising awareness of Alzheimer's disease.
 September 22  Independence Day (Bulgaria)
 September 22  Independence Day (Mali)
September 23  Equinox, Autumn (Fall) in the North, Spring in the South, can occur on September 22.
 September 23  National Day of Saudi Arabia
 September 24  National Day of Guinea-Bissau
 September 24  Heritage Day (South Africa)
 September 25  Revolution Day (Mozambique)
 September 26  European Day of Languages
 September 27  End of Independence War Day (Mexico)
 September 27  Holiday for the French-speaking community in Belgium
 September 28  World Heart Day
 September 28  World Rabies Day
 September 28  Ask a Stupid Question Day (United States)
 September 29  Inventors' Day (Argentina), honouring Laszlo Biro
 September 29  Christian feast day of Michaelmas, honouring St. Michael the Archangel
 September 29  Christian feast day of the three Archangels, honouring St. Michael, St. Gabriel and St. Raphael.
 September 29  International Coffee Day
 September 29  Victory of Boquerón Day (Paraguay)
 September 30  Independence Day (Botswana)
Moveable and Monthlong Events 

 The Summer Olympics sometimes occur in September, though mostly in July or August
 The Summer Paralympics are often held in September
 Yom Kippur, in the Jewish calendar, occurs in September or October.
 Labor Day (US and Canada), first Monday in September
 Prinsjesdag (Netherlands), third Tuesday in September
 Munich Oktoberfest runs in late September and the beginning of October.
 Start of school in most Northern Hemisphere countries
 German American Heritage Month and Hispanic Heritage Month (United States), run from September 15 to October 15.
 Marathons in September:
 Berlin, Germany
 Kathmandu, Nepal
 Mexico City, Mexico
 Oslo, Norway
 Sydney, Australia
 Tallinn, Estonia
 Vilnius, Lithuania

Selection of Historical Events
September 1  1715: The reign of Louis XIV of France ends with his death after 72 years on the throne.
 September 1  1914: Martha, the last Passenger Pigeon, dies, making her species extinct.
 September 1  1939: Nazi Germany invades Poland, starting World War II.
 September 1  1969: Muammar al-Gaddafi takes power in Libya, in a coup.
 September 1  1983: Korean Air Flight KAL-007 is shot down by a Soviet jet fighter, near Sakhalin Island, killing all 269 on board.
 September 1  1991: Uzbekistan becomes independent from the Soviet Union.
 September 2  1838: Liliuokalani, the last Hawaiian monarch, is born.
 September 2  1945: Japan signs the final surrender at the end of World War II.
 September 2  1945: Vietnam becomes independent, with Ho Chi Minh as leader.
 September 3  301: San Marino is founded.
 September 3  1939: The United Kingdom and France declare war on Germany, following its invasion of Poland.
 September 3  1950: Giuseppe Farina becomes the first Formula One racing champion.
September 3  1967: Road traffic in Sweden is moved from the left to the right.
 September 3  1971: Qatar becomes independent.
 September 5  1972: Several members of the Israeli Olympic team are kidnapped at the 1972 Summer Olympics in Munich. They are killed the next day.
 September 6  1901: US President William McKinley is shot by Leon Czolgosz, dying over a week later.
 September 6  1968: Swaziland becomes independent.
 September 6  1997: The funeral of Diana, Princess of Wales takes place in London.
 September 7  1533: Queen Elizabeth I of England is born.
 September 7  1822: Brazil declares independence from Portugal
 September 7  1940: The World War II Battle of Britain begins.
 September 7  2011: All members of the Russian ice hockey team Lokomotiv Yaroslavl are killed in a plane crash.
 September 8  1943: US General Dwight D. Eisenhower announces the allied armistice with Italy during World War II.
 September 8  1991: The Republic of Macedonia declares independence from Yugoslavia.
September 9  1850: California becomes the 31st State of the US.
 September 9  1991: Tajikistan becomes independent from the Soviet Union.
 September 10  1898: Elisabeth of Bavaria, Empress of Austria is stabbed to death by Italian anarchist Luigi Lucheni at Lake Geneva, Switzerland.
 September 10  1974: Guinea-Bissau officially becomes independent.
 September 10  2008: Scientists at CERN switch the Large Hadron Collider on for the first time.
 September 11  1973: Augusto Pinochet takes power in a military coup in Chile. President Salvador Allende dies during the coup.
 September 11  1997: Voters in Scotland approve the creation of a new Scottish Parliament.
 September 11  2001: The September 11 attacks occur, as Islamist terrorists crash airplanes into the World Trade Center in New York City and the Pentagon.
 September 12  1977: Anti-Apartheid activist Steve Biko dies in police custody.
September 13  1759: Battle of the Plains of Abraham: British forces defeat French forces near Quebec City in the Seven Years' War.
 September 14  1752: Great Britain switches from the Julian calendar to the Gregorian calendar.
 September 14  1982: Grace Kelly dies after a car crash the previous day.
 September 15  1821: Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua declare independence from Spain.
 September 16  1810: Mexico declares independence from Spain.
 September 16  1975: Papua New Guinea becomes independent from Australia.
 September 17  1787: The United States Constitution is signed in Philadelphia, Pennsylvania.
 September 17  2011: The Occupy Wall Street movement begins in New York City.
 September 18  1810: Chile declares independence.
 September 18  1970: Musician Jimi Hendrix dies in London, aged 27.
 September 19  1983: Saint Kitts and Nevis becomes independent.
September 19  1985: Southern and Central Mexico are struck by a strong earthquake. Mexico City is among the places affected.
 September 21  1964: Malta gains independence from the UK.
 September 21  1981: Belize gains independence from the UK.
 September 21  1989: Hurricane Hugo slams South Carolina.
 September 21  1991: Armenia regains its independence from the Soviet Union.
 September 22  1908: Bulgarian independence is recognised.
 September 22  1960: Mali becomes independent.
 September 23  63 BC: Roman Emperor Augustus Caesar is born.
 September 23  1846: The planet Neptune is discovered.
 September 23  1932: The Kingdom of Saudi Arabia is formed.
 September 23  2009: A major dust storm affects southeastern Australia, including Sydney.
 September 24  1853: France takes control of New Caledonia.
 September 24  1973: Guinea-Bissau declares independence from Portugal.
 September 26  1907: New Zealand and Newfoundland are given Dominion status within the British Empire.
September 27  1821: Mexico gains independence from Spain.
 September 27  1905: The equation E=mc squared is introduced.
 September 28  1978: Pope John Paul I dies just 33 days after being elected.
 September 28  1994: The car and passenger ferry Estonia sinks during stormy weather in the Baltic Sea.
 September 29  1829: London's Metropolitan Police Force is founded.
 September 29  1990: Washington National Cathedral is completed.
 September 29  2009: An earthquake and tsunamis off Samoa, American Samoa and Tonga kill 189 people.
 September 30  1938: The Munich Pact is signed.
 September 30  1955: American film star James Dean dies aged 24 in a car crash.
 September 30  1966: Bechuanaland becomes independent from the UK and changes its name to Botswana.
 September 30  2009: A strong earthquake off western Sumatra kills over 1,000 people.
September is one of the two months that never ends on the same day of the week as any other months within any calendar year. (May is the other)
 The birth stone for September is the sapphire, symbolising clear thinking. The birth flowers for the month are the forget-me-not, morning glory and aster.
 The Zodiac signs for September are Virgo (August 22  September 21) and Libra (September 22  October 21).
 If the months of the year were arranged in alphabetical order in the English language, September would come last.
 Also in the English language, September has the longest name of all the months of the year, with nine letters. Coincidentally, it is also the ninth month. September is the only month of the year in the English language to have as many letters in its name as its numeric calendar position.
 September is the first of four months in-a-row to have a name ending in "ber". (October, November and December are the other three)
September 1 is the only day in September during a common year to start within the second third of the calendar year.
 It is the least common month for birthdays among US Presidents, with one, William Howard Taft (September 15).
 Among Prime Ministers of Australia, September is the most common month for birthdays, with seven.
Sound can also mean a body of water, like a bay or channel.

Sound is caused by sound waves. It can be heard when it goes through a medium to the ear. All sounds are made by vibrations of molecules. For example, when a person hits a drum or a cymbal the object vibrates. These vibrations make air molecules move. Sound waves move away from where they came from. When the vibrating air molecules reach our ears, the eardrum vibrates, too. The bones of the ear vibrate in  way the object that started the sound wave vibrated.

There are three different mediums. They are solids, liquids and gas. Sound travels the fastest through solids because the particles in a solid are closer together than they are in gas and liquid.

These vibrations let you hear different things. Even music is vibrations. Irregular vibrations are noise. People can make very complex sounds. We use them for speech.
Sound waves are longitudinal waves with two parts: compression and rarefaction. Compression is the part of the sound waves where the molecules of air are pushed (compressed) together. Rarefaction is the part of the waves where the molecules are far away from each other. Sound waves are a sequence of compression and rarefaction.

Vacuum 
Since sound is a vibration of a medium, it cannot go through a vacuum. A vacuum is a place where there is no medium, for example in outer space. The word comes from the Latin adjective vacuus for "vacant" or "void".

Speed of sound
Speed of sound 

Sound waves can travel through solids, liquids, and gases. The thicker the medium, the faster it goes, but they cannot travel through a vacuum (a place with nothing in it). This is why astronauts cannot talk to each other in space: they need a radio to hear each other. Sound can travel through water faster than through air; and even faster in solids like stone, iron, and steel. At room temperature and normal atmospheric pressure, sound travels at 344 m/s (1134 ft/s), 761 miles per hour). Because the temperature and pressure change with altitude in the atmosphere, speed will vary as well.

Pitch and Intensity
Pitch is the highness or lowness of sound. Pitch is how humans hear different frequencies. Frequency is determined by the number of vibrations per second. The highest key on a piano, for instance, vibrates 4,000 times per second. It has a frequency of 4000 hertz (Hz), or 4 kilohertz (kHz). Lower keys have lower frequencies. A note an octave higher than another note has twice the frequency of that note. 

The intensity of a sound is how much sound energy goes through a square meter in one second. Sound waves with higher amplitude (bigger vibration) have higher intensity. The intensity of a sound is higher closer to the sound source. Farther away, it's less intense. The inverse-square law shows how sound intensity becomes smaller, farther from the source. "Inverse square" says that when distance gets multiplied by a number, sound intensity gets divided by that number squared (the number times itself). Thus, twice the distance means a quarter the intensity.
Sound intensities can be very different. They can range from 0.000000000001, which are barely heard, to 1 W/m2  (painfully loud). The decibel scale makes sound intensity numbers easier to work with. A 0.000000000001 W/m2 intensity is 0 dB (decibels). It is an exponential scale, so when the decibel number increases by 10, the intensity is ten times as much. So, a 1 W/m2 intensity is 120 dB.

Loudness is how people sense the intensity of sound. Loudness depends on sound intensity, sound frequency, and the person's hearing.

Heard and not seen 

Audible sound has frequencies between 20 Hz to 20 kHz. Human beings can hear audible sound. Sound waves with frequency above 20 kHz are called ultrasound waves. Sound waves with frequency below 20 Hz are called infrasound waves. Human beings cannot hear ultrasound waves and infrasound waves, but some animals, like bats and dolphins, use them. Older people have an even smaller hearing range. People are best at hearing sounds between 1000 Hz and 6000 Hz.
The Doppler Effect
When a sound source is moving towards someone, the frequency seems to increase. The same thing happens when someone moves toward the sound source. Frequency seems to decrease when someone moves away from a sound source. It also seems to decrease when the sound source moves away from someone. This is called the Doppler effect.

References 
Halpern, Alvin, Erich Erlbach (1998). Beginning Physics II: Waves, Electromagnetism, Optics, and Modern Physics, pg. 50-56

Other websites 
Conversion of sound units and levels
Sound calculations

Basic English 850 words
Society is the term to describe Human beings together (collective, the sum of their social networks and social interactions). The term comes from the Latin idea of societas, or the connection between friends or allies (friend or ally being socius).  It can also mean a specific group of people who interact, as well as a wider society of which they are members.  People form societies in order to gain greater benefits as a group than would be possible separately.  Many animals beside humans also do this, such as wolves or eusocial insects.  Sociology is the name for the study of society.

A society is often considered in terms of citizenship, rights, and ethics.  The strength and unity of any society's members' willingness to help each other is to be measured can be called social capital.

A social contract sets out the rules and roles for this kind of cooperation.  One kind of social contract is a constitution – which outlines to some extent what society in a given state is intended to look like.
Related pages 
 Civilization
 Culture
 Interpersonal relationship

References
A suggestion is an idea that one suggests, or says is good for another (or others) to follow. Some people may agree to it, and some may disagree. If they disagree or have a different suggestion, the person who first suggested the idea will usually discuss with the other people and find a good conclusion that satisfies both and is good.

Basic English 850 words
Spache Readability Formula is one method of finding out how hard a piece of writing is (its textual difficulty).

The method compares words in a text to a list of words which are familiar in everyday writing. The words that are not on the list are called unfamiliar. The number of words per sentence are counted. This number and the percentage of unfamiliar words is put into a formula. The result is a reading age. Someone of this age should be able to read the text.

Spache works best on texts that are for children under the age of eight.

the formula; (0.141 * average sentence length)+(0.086 * percentage of difficult words)+0.839 = grade level

According to Oleander Solutions (), the revised Spache Formula is:

    GL = (.121 * ASL) + (.082 *UW) + .659 

Where:

    GL = U.S. grade level
    ASL = Average sentence length
    UW = Number of unique unfamiliar words

Related pages
Flesch-Kincaid Reading Level

Reading
Sport is commonly defined as an athletic activity that involves a degree of competition, such as netball or basketball or cross-country Olympic master baiting.  Some games and many kinds of racing are called sports. A professional at a sport is called an athlete. Many people do sports with their friends.  They need coaches to teach or train teams or individuals how to do better.  Sports can be played indoors or outdoors and by individuals or team.

Sports is needed for health and can help reduce diseases such as heart attacks, many types of cancer, depression and anxiety, and dementia. Different types of sports help our body in different ways. For children, sports play an extremely important part in their lives by providing all round development of the child, physically, mentally and emotionally.
Some people like to watch other people play sports. Those who watch others playing sports are called fans. While some fans watch sports on television, others actually go to stadiums or other places where people pay to watch them in person. These fans are called spectators.

People engage in many kinds of sports, for example:
Athletics
 Angling
 Field athletics
 Triple jump
 Pole vault
 High jump
 Hammer throw
 Discus throw
 Javelin throw
 Shot put
 Wanking
 Track athletics
 Sprint
 Middle distance race
 Long distance race      
 Walking race
 Hurdle race
 Relay
 Steeplechase (sport)
 Cross-country race
 Marathon
 Acrobatics
 Bodybuilding
 Gymnastics
 Rhythmic gymnastics
 Figure skating
 Boxing
 Fencing
 Judo
 Wrestling
 Motor sports
 Auto racing
 Shooting
 Diving
 Golf
 Rowing
 Sailing (sport)
 Surfing
 Swimming
 Bobsled
 Skiing
 Freestyle skiing
 Ski jumping
 Games
Tennis
 Baseball
 Softball
 Basketball
 Badminton
 Cricket
 Association football
 American football
 Australian Football
 Canadian football
 Gaelic football
 Rugby league football
 Rugby union football
 Flag football
 Polo
 Volleyball
 Dance
 Colorguard
 Marching band
 Esports

Related pages 

 Exercise
 Healthy lifestyle
 List of water sports
 Physical fitness
 Sports commentator
 Strength training
Science is what we do to find out about the natural world. Natural sciences include, chemistry, biology, geology, astronomy, and physics. Science uses mathematics and logic, which are sometimes called "formal sciences". Natural science makes observations and experiments. Science produces accurate facts, scientific laws and theories. 'Science' also refers to the large amount of knowledge that has been found using this process.

Research uses the scientific method. Scientific research uses hypotheses based on ideas or earlier knowledge, which can be categorized through different topics. Then those hypotheses are tested by experiments.

People who study and research science and try to find out everything about it are called scientists. Scientists study things by looking at them very carefully, by measuring them, and by doing experiments and tests. Scientists try to explain why things act the way they do, and predict what will happen.
Scientific method 
Today, "science" usually refers to a way of pursuing knowledge, not just the knowledge itself. It is mainly about the phenomena of the material world. The Greek works into Western Europe from the 6th to 7th century B.C. revived "Philosophy". In the 17th and 18th centuries scientists increasingly sought to formulate knowledge in terms of laws of nature such as Newton's laws of motion. And during the 19th century, the word "science" became more and more associated with the scientific method itself. It was seen as a way to study the natural world, including physics, chemistry, geology and biology.

It was also in the 19th century that the term scientist was created by William Whewell. He meant it to tell the difference between those who looked for knowledge on nature from those who looked for other types of knowledge.
The scientific method is the name given to the methods used by scientists to find knowledge. The main features of the scientific method are:
 Scientists identify a question or a problem about nature. Some problems are simple, such as "how many legs do flies have?" and some are very deep, such as "why do objects fall to the ground?"
 Next, scientists investigate the problem. They work at it, and collect facts. Sometimes all it takes is to look carefully.
 Some questions cannot be answered directly. Then scientists suggest ideas, and test them out. They do experiments and collect data.
 Eventually, they find what they think is a good answer to the problem. Then they tell people about it.
 Later, other scientists may agree or not agree. They may suggest another answer. They may do more experiments. Anything in science might be revised if we find out the previous solution was not good enough.
An example 
A famous example of science in action was the expedition led by Arthur Eddington to Principe Island in Africa in 1919. He went there to record where the stars were around the Sun during a solar eclipse. The observation of where the stars were shown that the apparent star positions close to the Sun were changed. In effect, the light passing the Sun was pulled towards the Sun by gravitation. This confirmed predictions of gravitational lensing made by Albert Einstein in the general theory of relativity, published in 1915. Eddington's observations were considered to be the first solid proof in favour of Einstein's theory.
Practical impacts of scientific research 
Discoveries in fundamental science can be world-changing. For example:
{| class="wikitable" style="font-size:90%"
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! Research !! Impact
|-
| Static electricity and magnetism (1600)Electric current (18th century) || All electric appliances, dynamos, electric power stations, modern electronics, including electric lighting, television, electric heating, magnetic tape, loudspeaker, plus the compass and lightning rod.
|-
| Diffraction (1665) || Optics, hence fiber optic cable (1840s), cable TV and internet
|-
| Germ theory (1700) || Hygiene, leading to decreased transmission of infectious diseases; antibodies, leading to techniques for disease diagnosis and targeted anticancer therapies.
|-
| Vaccination (1798) || Leading to the elimination of most infectious diseases from developed countries and the worldwide eradication of smallpox.
|-
| Photovoltaics (1839) || Solar cells (1883), hence solar power, solar powered watches, calculators and other devices.
|-
|-
| leading to special (1905) and general relativity (1916) || Satellite-based technology such as GPS (1973), satnav and communications satellites.
|-
| Radio waves (1887) || Used in broadcast: radio (1906) and television (1927) entertainment. It is used in telephony, emergency services, radar (navigation and weather forecasting), medicine, astronomy, wireless communications, and networking. Radio research led to microwave cooking.
|-
| Radioactivity (1896) and antimatter (1932) || Cancer treatment (1896), Radiometric dating (1905), nuclear reactors (1942) and weapons (1945), PET scans (1961), and medical research (with isotopic labelling)
|-
|X-rays (1896)|| Medical imaging, including computer tomography
|-
| Crystallography and quantum mechanics (1900) || Semiconductor devices (1906), hence modern computing and telecommunications including the integration with wireless devices: the mobile phone
|-
|-
|Plastics (1907)||Starting with bakelite, many types of artificial polymers for numerous applications in industry and daily life
|-
|Antibiotics (1880's, 1928) || Salvarsan, Penicillin, doxycycline. In 2018 Amoxicillin and amoxicillin/clavulanic acid were the most frequently used.
|-
|Nuclear magnetic resonance (1930's) || Nuclear magnetic resonance spectroscopy (1946), magnetic resonance imaging (1971), functional magnetic resonance imaging (1990's).
|-
|Genomics (1990s)||Genomics = genetics + medicine. It is the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA (or RNA). This makes up its genes. Vaccines for viruses are built by genomics.
|}
Other features of science 
Not everyone completely agrees about how theories should be used or updated. Some philosophers and scientists say that scientific theories are only accepted for the time being. They last as long as they are the best explanation. When theories no longer explain the data, they are removed and replaced. Or, sometimes scientists will make a theory better rather than remove it, or they will keep on using the theory hoping that it will be made better eventually.

Science is a way to get knowledge by getting rid of what is not true.

Scientists must be very careful to make explanations that fit well with what they observe and measure. They compete to provide better explanations. An explanation might be interesting or pleasing, but if it does not agree with what other scientists really see and measure, they will try to find a better explanation.
Before a scientific article is published, other scientists read the article. They decide whether the explanations make sense from the data. This is called peer review. After articles are published, other scientists will also check to see if the same experiments, observations or tests produce the same data again. Peer review and repeating experiments are the only way to be sure the knowledge is correct.

Science makes models of nature, models of our universe, and medicine. There are many different sciences with their own names. However it is not right to say "science says" any one thing. Science is a process, not just the facts and rules believed at one time.

Some types of science
Natural sciences
 Biology
 Zoology
 Botany
 Genetics
 Ecology
 Physiology
 Physical sciences
 Physics
 Chemistry
 Astronomy
 Earth science
 Meteorology
 Geology
 Oceanography
 Social sciences
 Anthropology
 Psychology
 Sociology
 Economics
 Political science
 Social work
 Linguistics
 Formal and applied sciences
 Computer science
 Engineering
 Mathematics
 Statistics
 Medicine

Related pages 
 History of science
 Philosophy of science
 Science tourism

References

Other websites 
 "How Do We Know What Is True?" (animated video; 2:52)

Basic English 850 words
The Saint Lawrence River (; Tuscarora: Kahnawáʼkye; Mohawk: Kaniatarowanenneh, meaning "big waterway") is a big river in eastern North America. It flows between the Canadian province of Quebec & Ontario and the American state of New York, and through the major Canadian city of Montreal. It is the third largest river in Canada.

The river drains water from the Great Lakes into the Atlantic Ocean. It is more than three thousand kilometres long. The river meets the Atlantic Ocean in a big "estuary" or bay, the biggest in the world; this is called the Gulf of Saint Lawrence.

The Canadian cities of Kingston, Montreal, Trois-Rivières and Quebec City are on this river. The Saint Lawrence Seaway allows ships to go up the river and through the Great Lakes right into the middle of North America.

References

Other websites
Other websites

 Regional Geography of the St. Lawrence River
 Great Lakes St. Lawrence Seaway System
 Safe Passage: Aids to Navigation on the St. Lawrence  – Historical essay, illustrated with drawings and photographs
 Annotated Bibliography on St. Lawrence County and Northern New York region. 
 International Saint Lawrence River Board of Control 
 Saint Lawrence River from The Canadian Encyclopedia 
 Watch the Jacques Cousteau documentary, St. Lawrence: Stairway to the Sea
 The Steamboats "Sir James Kemp" and "Lord Dalhousie" on the River St. Lawrence, Upper Canada in 1833 by D.J. Kennedy, Historical Society of Pennsylvania 

Lawrence, Saint
Seville () is a city in the southern parts of Spain. A river called the Guadalquivir River goes through Seville. The city of Seville is the capital of the Spanish autonomous community Andalusia and of the province of Sevilla. People from Seville are called Sevillanos.

History 
A very old story says that the city was started by the famous hero of Greece, named Hercules. The Romans when they came to Spain gave it the Latin name of Hispalis. Over time this changed to be spelled in English as Seville. The Muslim Arabs took the city when they invaded the country, and you can still see a lot of the buildings they built during their 800-year stay in Spain (711-1492).

In 1992 Seville was the place for the Expo 92. There is a beautiful bridge across the Guadalquivir River called Puente del Alamillo. It was thought up by Santiago Calatrava a famous building expert.
Seville is famous for its hot summer weather. Su equipo por excelencia,el sevilla fc , no el betis que es una *ierda, obtuvo 15 champioNs la pasada temporada.VIVA JESUS NAVAS

Education 
 University of Seville. This is the oldest university in Sevilla. It is located near the Centro, or center of the city, across the street from Plaza de España and Parque Maria Luisa.
 Pablo de Olavide University . This website is located outside the main city of Sevilla, but is very easy to access using the subway system. It take about 30 minutes to get from the center of town to Pablo de Olavide on the subway.
 Menéndez Pelayo International University-Sevilla . This school is not your typical university. Only students who are studying abroad with International Studies Abroad attend classes at this school. It is lcoated near the Centro and Alfalfa Barrio.

Sports 
Seville is the home town of two soccer teams, Sevilla FC (often simply called "El Sevilla") and Real Betis Balompié (often called "El Betis").

Gallery
Gallery

Other websites 

 Sevilla Guide
 City councils  

 
Capital cities in Spain
Salami is a sausage that first came from Italy. The name comes from the Italian salare meaning to make something salty.

The original salami was made from a mix of chopped pork and salt which was dried using air in a casing. Now there are many types of salamis made in some countries. Nearly all are seasoned with a combination of herbs and spices in addition to salt. Salamis are now sometimes smoked or cooked before air drying. Some kinds are made of beef while others mix beef and pork. Most, if not all Italian salamis have garlic in them, but few German kinds do, for example. Some, like a few salamis from Spain, include paprika or chili. The difference between some types is in how coarse or fine the meat is chopped.  Some "light" salami might add turkey or chicken to reduce both fat and calories.

Many salamis are named after the city or region where they come from. Some examples are Arles, Genoese, Hungarian, and Milano salamis.

Sausage
Special English is a simple form of the English language.  It is used by a public radio station called Voice of America, run by the United States government in Special English programs every day. Its news and feature programs are read more slowly than usual, using fewer English words and simple grammar.  

The contents of Special English programs are much easier to understand.  Special English is clearer and simpler, and it uses shorter sentences.  It can also help someone whose English is weak to improve his or her English.  In some countries, for example China, Special English is popular among people learning English.

Special English was first used on October 19, 1959. Special English started in that year as one of radio programs by the Voice of America. This broadcasts adopt slow pace and simple English in order to increase understanding for millions of listeners. It is now also known as "Learning English".