title: Quantum mechanics

paragraphs: Quantum mechanics explains how the universe works at a scale smaller than atoms. It is also called quantum physics or quantum theory. Mechanics is the part of physics that explains how things move and "quantum" is the Latin word for 'how much' . A quantum of energy is the least amount possible (or the least extra amount), and quantum mechanics describes how that energy moves or interacts.

paragraphs: Atoms used to be considered the smallest building blocks of matter but modern science has shown that there are even smaller particles, like protons, neutrons and electrons. Quantum mechanics describes how the particles that make up atoms work.

paragraphs: Quantum mechanics also tells us how electromagnetic waves (like light) work. Wave–particle duality means that particles behave like waves and waves behave like particles. (They are not two kinds of thing, they are something like both: this is their "duality".) Much of modern physics and chemistry can be described and understood using the mathematical rules of quantum mechanics.

paragraphs: The mathematics used to study subatomic particles and electromagnetic waves is very complex because they act in very strange ways.

paragraphs: Photons are particles that are point-sized, smaller than atoms. Photons are like "packets" or packages of energy. Light sources such as candles or lasers produce light in bits called photons.

paragraphs: The more photons a lamp produces, the brighter the light. Light is a form of energy that behaves like the waves in water or radio waves. The distance between the top of one wave and the top of the next wave is called a 'wavelength'. Each photon carries a certain amount, or 'quantum', of energy depending on its wavelength.

paragraphs: A light's color depends on its wavelength. The color violet (the bottom or innermost color of the rainbow) has a wavelength of about 400 nm ("nanometers") which is 0.00004 centimeters or 0.000016 inches. Photons with wavelengths of 10-400 nm are called ultraviolet (or UV) light. Such light cannot be seen by the human eye. On the other end of the spectrum, red light is about 700 nm. Infrared light is about 700 nm to 300,000 nm. Human eyes are not sensitive to infrared light either.

paragraphs: Wavelengths are not always so small. Radio waves have longer wavelengths. The wavelengths for an FM radio can be several meters in length (for example, stations transmitting on 99.5 FM are emitting radio energy with a wavelength of about 3 meters, which is about 10 feet). Each photon has a certain amount of energy related to its wavelength. The shorter the wavelength of a photon, the greater its energy. For example, an ultraviolet photon has more energy than an infrared photon.

paragraphs: Wavelength and frequency (the number of times the wave crests per second) are inversely proportional, which means a longer wavelength will have a lower frequency, and vice versa. If the color of the light is infrared (lower in frequency than red light), each photon can heat up what it hits. So, if a strong infrared lamp (a heat lamp) is pointed at a person, that person will feel warm, or even hot, because of the energy stored in the many photons. The surface of the infrared lamp may even get hot enough to burn someone who may touch it.

paragraphs: Humans cannot see infrared light, but we can feel the radiation in the form of heat. For example, a person walking by a brick building that has been heated by the sun will feel heat from the building without having to touch it.

paragraphs: The mathematical equations of quantum mechanics are abstract, which means it is impossible to know the exact physical properties of a particle (like its position or momentum) for sure. Instead, a mathematical function called the wavefunction provides information about the probability with which a particle has a given property. For example, the wavefunction can tell you what the probability is that a particle can be found in a certain location, but it can't tell you where it is for sure. Because of this uncertainty and other factors, you cannot use classical mechanics (the physics that describe how large objects move) to predict the motion of quantum particles.

paragraphs: Ultraviolet light is higher in frequency than violet light, such that it is not even in the visible light range. Each photon in the ultraviolet range has a lot of energy, enough to hurt skin cells and cause a sunburn. In fact, most forms of sunburn are not caused by heat; they are caused by the high energy of the sun's UV rays damaging your skin cells. Even higher frequencies of light (or electromagnetic radiation) can penetrate deeper into the body and cause even more damage. X-rays have so much energy that they can go deep into the human body and kill cells. Humans cannot see or feel ultraviolet light or x-rays. They may only know they have been under such high frequency light when they get a radiation burn. Areas where it is important to kill germs often use ultraviolet lamps to destroy bacteria, fungi, etc. X-rays are sometimes used to kill cancer cells.

paragraphs: Quantum mechanics started when it was discovered that if a particle has a certain frequency, it must also have a certain amount of energy. Energy is proportional to frequency (E ∝ f). The higher the frequency, the more energy a photon has, and the more damage it can do. Quantum mechanics later grew to explain the internal structure of atoms. Quantum mechanics also explains the way that a photon can interfere with itself, and many other things never imagined in classical physics.

paragraphs: Max Planck discovered the relationship between frequency and energy. Nobody before had ever guessed that frequency is directly proportional to energy (this means that as one of them doubles, the other does, too). Under what are called natural units, then the number representing the frequency of a photon would also represent its energy. The equation would then be:

paragraphs: But the way physics grew, there was no natural connection between the units that were used to measure energy and the units commonly used to measure time (and therefore frequency). So the formula that Planck worked out to make the numbers all come out right was:

paragraphs: or, energy equals h times frequency. This h is a number called Planck's constant after its discoverer.

paragraphs: Quantum mechanics is based on the knowledge that a photon of a certain frequency means a photon of a certain amount of energy. Besides that relationship, a specific kind of atom can only give off certain frequencies of radiation, so it can also only give off photons that have certain amounts of energy.

paragraphs: Isaac Newton thought that light was made of very small things that we would now call particles (he referred to them as "Corpuscles"). Christiaan Huygens thought that light was made of waves. Scientists thought that a thing cannot be a particle and a wave at the same time.

paragraphs: Scientists did experiments to find out whether light was made of particles or waves. They found out that both ideas were right — light was somehow both waves and particles. The Double-slit experiment performed by Thomas Young showed that light must act like a wave. The Photoelectric effect discovered by Albert Einstein proved that light had to act like particles that carried specific amounts of energy, and that the energies were linked to their frequencies. This experimental result is called the "wave-particle duality" in quantum mechanics. Later, physicists found out that everything behaves both like a wave and like a particle, not just light. However, this effect is much smaller in large objects.

paragraphs: Here are some of the people who discovered the basic parts of quantum mechanics: Max Planck, Albert Einstein, Satyendra Nath Bose, Niels Bohr, Louis de Broglie, Max Born, Paul Dirac, Werner Heisenberg, Wolfgang Pauli, Erwin Schrödinger, John von Neumann, and Richard Feynman. They did their work in the first half of the 20th century.

paragraphs: Quantum mechanics formulae and ideas were made to explain the light that comes from glowing hydrogen. The quantum theory of the atom also had to explain why the electron stays in its orbit, which other ideas were not able to explain. It followed from the older ideas that the electron would have to fall in to the center of the atom because it starts out being kept in orbit by its own energy, but it would quickly lose its energy as it revolves in its orbit. (This is because electrons and other charged particles were known to emit light and lose energy when they changed speed or turned.)

paragraphs: Hydrogen lamps work like neon lights, but neon lights have their own unique group of colors (and frequencies) of light. Scientists learned that they could identify all elements by the light colors they produce. They just could not figure out how the frequencies were determined.

paragraphs: Then, a Swiss mathematician named Johann Balmer figured out an equation that told what λ (lambda, for wave length) would be:

paragraphs: where "B" is a number that Balmer determined to be equal to 364.56 nm.

paragraphs: This equation only worked for the visible light from a hydrogen lamp. But later, the equation was made more general:

paragraphs: where "R" is the Rydberg constant, equal to 0.0110 nm, and "n" must be greater than "m".

paragraphs: Putting in different numbers for m and n, it is easy to predict frequencies for many types of light (ultraviolet, visible, and infared). To see how this works, go to Hyperphysics and go down past the middle of the page. (Use H = 1 for hydrogen.)

paragraphs: In 1908, Walter Ritz made the Ritz combination principle that shows how certain gaps between frequencies keep repeating themselves. This turned out to be important to Werner Heisenberg several years later.

paragraphs: In 1905, Albert Einstein used Planck's idea to show that a beam of light is made up of a stream of particles called photons. The energy of each photon depends on its frequency. Einstein's idea is the beginning of the idea in quantum mechanics that all subatomic particles like electrons, protons, neutrons, and others are both waves and particles at the same time. (See picture of atom with the electron as waves at atom.) This led to a theory about subatomic particles and electromagnetic waves called "wave-particle duality". This is where particles and waves were neither one nor the other, but had certain properties of both.

paragraphs: In 1913, Niels Bohr came up with the idea that electrons could only take up certain orbits around the nucleus of an atom. Under Bohr's theory, the numbers called m and n in the equation above could represent orbits. Bohr's theory said electrons could begin in some orbit m and end up in some orbit n, or an electron could begin in some orbit n and end up in some orbit m so if a photon hits an electron, its energy will be absorbed, and the electron will move to a higher orbit because of that extra energy. Under Bohr's theory, if an electron falls from a higher orbit to a lower orbit, then it will have to give up energy in the form of a photon. The energy of the photon will equal the energy difference between the two orbits, and the energy of a photon makes it have a certain frequency and color. Bohr's theory provided a good explanation of many aspects of subatomic phenomena, but failed to answer why each of the colors of light produced by glowing hydrogen (and by glowing neon or any other element) has a brightness of its own, and the brightness differences are always the same for each element.

paragraphs: By the time Niels Bohr came out with his theory, most things about the light produced by a hydrogen lamp were known, but scientists still could not explain the brightness of each of the lines produced by glowing hydrogen.

paragraphs: Werner Heisenberg took on the job of explaining the brightness or "intensity" of each line. He could not use any simple rule like the one Balmer had come up with. He had to use the very difficult math of classical physics that figures everything out in terms of things like the mass (weight) of an electron, the charge (static electric strength) of an electron, and other tiny quantities. Classical physics already had answers for the brightness of the bands of color that a hydrogen lamp produces, but the classical theory said that there should be a continuous rainbow, and not four separate color bands. Heisenberg's explanation is:

paragraphs: There is some law that says what frequencies of light glowing hydrogen will produce. It has to predict spaced-out frequencies when the electrons involved are moving between orbits close to the nucleus (center) of the atom, but it also has to predict that the frequencies will get closer and closer together as we look at what the electron does in moving between orbits farther and farther out. It will also predict that the intensity differences between frequencies get closer and closer together as we go out. Where classical physics already gives the right answers by one set of equations the new physics has to give the same answers but by different equations.

paragraphs: Classical physics uses the methods of the French mathematician Fourier to make a math picture of the physical world, and it uses collections of smooth curves that go together to make one smooth curve that gives, in this case, intensities for light of all frequencies from some light. But it is not right because that smooth curve only appears at higher frequencies. At lower frequencies, there are always isolated points and nothing connects the dots. So, to make a map of the real world, Heisenberg had to make a big change. He had to do something to pick out only the numbers that would match what was seen in nature. Sometimes people say he "guessed" these equations, but he was not making blind guesses. He found what he needed. The numbers that he calculated would put dots on a graph, but there would be no line drawn between the dots. And making one "graph" just of dots for every set of calculations would have wasted lots of paper and not have gotten anything done. Heisenberg found a way to efficiently predict the intensities for different frequencies and to organize that information in a helpful way.

paragraphs: Just using the empirical rule given above, the one that Balmer got started and Rydberg improved, we can see how to get one set of numbers that would help Heisenberg get the kind of picture that he wanted:

paragraphs: The rule says that when the electron moves from one orbit to another it either gains or loses energy, depending on whether it is getting farther from the center or nearer to it. So we can put these orbits or energy levels in as headings along the top and the side of a grid. For historical reasons the lowest orbit is called n, and the next orbit out is called n - a, then comes n - b, and so forth. It is confusing that they used negative numbers when the electrons were actually gaining energy, but that is just the way it is.

paragraphs: Since the Rydberg rule gives us frequencies, we can use that rule to put in numbers depending on where the electron goes. If the electron starts at n and ends up at n, then it has not really gone anywhere, so it did not gain energy and it did not lose energy. So the frequency is 0. If the electron starts at n-a and ends up at n, then it has fallen from a higher orbit to a lower orbit. If it does so then it loses energy, and the energy it loses shows up as a photon. The photon has a certain amount of energy, e, and that is related to a certain frequency f by the equation e = h f. So we know that a certain change of orbit is going to produce a certain frequency of light, f. If the electron starts at n and ends up at n - a, that means it has gone from a lower orbit to a higher orbit. That only happens when a photon of a certain frequency and energy comes in from the outside, is absorbed by the electron and gives it its energy, and that is what makes the electron go out to a higher orbit. So, to keep everything making sense, we write that frequency as a negative number. There was a photon with a certain frequency and now it has been taken away.

paragraphs: So we can make a grid like this, where f(a←b) means the frequency involved when an electron goes from energy state (orbit) b to energy state a (Again, sequences look backwards, but that is the way they were originally written.):

paragraphs: Heisenberg did not make the grids like this. He just did the math that would let him get the intensities he was looking for. But to do that he had to multiply two amplitudes (how high a wave measures) to work out the intensity. (In classical physics, intensity equals amplitude squared.) He made an odd-looking equation to handle this problem, wrote out the rest of his paper, handed it to his boss, and went on vacation. Dr. Born looked at his funny equation and it seemed a little crazy. He must have wondered, "Why did Heisenberg give me this strange thing? Why does he have to do it this way?" Then he realized that he was looking at a blueprint for something he already knew very well. He was used to calling the grid or table that we could write by doing, for instance, all the math for frequencies, a matrix. And Heisenberg's weird equation was a rule for multiplying two of them together. Max Born was a very, very good mathematician. He knew that since the two matrices (grids) being multiplied represented different things (like position (x,y,z) and momentum (mv), for instance), then when you multiply the first matrix by the second you get one answer and when you multiply the second matrix by the first matrix you get another answer. Even though he did not know about matrix math, Heisenberg already saw this "different answers" problem and it had bothered him. But Dr. Born was such a good mathematician that he saw that the difference between the first matrix multiplication and the second matrix multiplication was always going to involve Planck's constant, h, multiplied by the square root of negative one, i. So within a few days of Heisenberg's discovery they already had the basic math for what Heisenberg liked to call the "indeterminacy principle." By "indeterminate" Heisenberg meant that something like an electron is just not pinned down until it gets pinned down. It is a little like a jellyfish that is always squishing around and cannot be "in one place" unless you kill it. Later, people got in the habit of calling it "Heisenberg's uncertainty principle," which made many people make the mistake of thinking that electrons and things like that are really "somewhere" but we are just uncertain about it in our own minds. That idea is wrong. It is not what Heisenberg was talking about. Having trouble measuring something is a problem, but it is not the problem Heisenberg was talking about.

paragraphs: Heisenberg's idea is very hard to grasp, but we can make it clearer with an example. First, we will start calling these grids "matrices," because we will soon need to talk about matrix multiplication.

paragraphs: Suppose that we start with two kinds of measurements, position (q) and momentum (p). In 1925, Heisenberg wrote an equation like this one:

paragraphs: He did not know it, but this equation gives a blueprint for writing out two matrices (grids) and for multiplying them. The rules for multiplying one matrix by another are a little messy, but here are the two matrices according to the blueprint, and then their product:

paragraphs: The matrix for the product of the above two matrices as specified by the relevant equation in Heisenberg's 1925 paper is:

paragraphs: If the matrices were reversed, the following values would result:

paragraphs: Note how changing the order of multiplication changes the numbers, step by step, that are actually multiplied.

paragraphs: The work of Werner Heisenberg seemed to break a log jam. Very soon, many different other ways of explaining things came from people such as Louis de Broglie, Max Born, Paul Dirac, Wolfgang Pauli, and Erwin Schrödinger. The work of each of these physicists is its own story. The math used by Heisenberg and earlier people is not very hard to understand, but the equations quickly grew very complicated as physicists looked more deeply into the atomic world.

paragraphs: In the early days of quantum mechanics, Albert Einstein suggested that if it were right then quantum mechanics would mean that there would be "spooky action at a distance." It turned out that quantum mechanics was right, and that what Einstein had used as a reason to reject quantum mechanics actually happened. This kind of "spooky connection" between certain quantum events is now called "quantum entanglement".

paragraphs: When an experiment brings two things (photons, electrons, etc.) together, they must then share a common description in quantum mechanics. When they are later separated, they keep the same quantum mechanical description or "state." In the diagram, one characteristic (e.g., "up" spin) is drawn in red, and its mate (e.g., "down" spin) is drawn in blue. The purple band means that when, e.g., two electrons are put together the pair shares both characteristics. So both electrons could show either up spin or down spin. When they are later separated, one remaining on Earth and one going to some planet of the star Alpha Centauri, they still each have both spins. In other words, each one of them can "decide" to show itself as a spin-up electron or a spin-down electron. But if later on someone measures the other one, it must "decide" to show itself as having the opposite spin.

paragraphs: Einstein argued that over such a great distance it was crazy to think that forcing one electron to show its spin would then somehow make the other electron show an opposite characteristic. He said that the two electrons must have been spin-up or spin-down all along, but that quantum mechanics could not predict which characteristic each electron had. Being unable to predict, only being able to look at one of them with the right experiment, meant that quantum mechanics could not account for something important. Therefore, Einstein said, quantum mechanics had a big hole in it. Quantum mechanics was incomplete.

paragraphs: Later, it turned out that experiments showed that it was Einstein who was wrong.

paragraphs: In 1925, Werner Heisenberg described the Uncertainty principle, which says that the more we know about where a particle is, the less we can know about how fast it is going and in which direction. In other words, the more we know about the speed and direction of something small, the less we can know about its position. Physicists usually talk about the momentum in such discussions instead of talking about speed. Momentum is just the speed of something in a certain direction times its mass.

paragraphs: The reason behind Heisenberg's uncertainty principle says that we can never know both the location and the momentum of a particle. Because light is an abundant particle, it is used for measuring other particles. The only way to measure it is to bounce the light wave off of the particle and record the results. If a high energy, or high frequency, light beam is used, we can tell precisely where it is, but cannot tell how fast it was going. This is because the high energy photon transfers energy to the particle and changes the particle's speed. If we use a low energy photon, we can tell how fast it is going, but not where it is. This is because we are using light with a longer wavelength. The longer wavelength means the particle could be anywhere along the stretch of the wave.

paragraphs: The principle also says that there are many pairs of measurements for which we cannot know both of them about any particle (a very small thing), no matter how hard we try. The more we learn about one of such a pair, the less we can know about the other.

paragraphs: Even Albert Einstein had trouble accepting such a bizarre concept, and in a well-known debate said, "God does not play dice".

paragraphs: To this, Danish physicist Niels Bohr famously responded, "Einstein, don't tell God what to do".

paragraphs: Electrons surround every atom's nucleus. Chemical bonds link atoms to form molecules. A chemical bond links two atoms when electrons are shared between those atoms. Thus QM is the physics of the chemical bond and of chemistry. QM helps us understand how molecules are made, and what their properties are.

paragraphs: QM can also help us understand big things, such as stars and even the whole universe. QM is a very important part of the theory of how the universe began called the Big Bang.

paragraphs: Everything made of matter is attracted to other matter because of a fundamental force called gravity. Einstein's theory that explains gravity is called the theory of general relativity. A problem in modern physics is that some conclusions of QM do not seem to agree with the theory of general relativity.

paragraphs: QM is the part of physics that can explain why all electronic technology works as it does. Thus QM explains how computers work, because computers are electronic machines. But the designers of the early computer hardware of around 1950 or 1960 did not need to think about QM. The designers of radios and televisions at that time did not think about QM either. However, the design of the more powerful integrated circuits and computer memory technologies of recent years does require QM.

paragraphs: QM has also made possible technologies such as:

paragraphs: QM is a challenging subject for several reasons:

paragraphs: QM describes nature in a way that is different from how we usually think about science. It tells us how likely to happen some things are, rather than telling us that they certainly will happen.

paragraphs: One example is Young's double-slit experiment. If we shoot single photons (single units of light) from a laser at a sheet of photographic film, we will see a single spot of light on the developed film. If we put a sheet of metal in between, and make two very narrow slits in the sheet, when we fire many photons at the metal sheet, and they have to go through the slits, then we will see something remarkable. All the way across the sheet of developed film we will see a series of bright and dark bands. We can use mathematics to tell exactly where the bright bands will be and how bright the light was that made them, that is, we can tell ahead of time how many photons will fall on each band. But if we slow the process down and see where each photon lands on the screen we can never tell ahead of time where the next one will show up. We can know for sure that it is most likely that a photon will hit the center bright band, and that it gets less and less likely that a photon will show up at bands farther and farther from the center. So we know for sure that the bands will be brightest at the center and get dimmer and dimmer farther away. But we never know for sure which photon will go into which band.

paragraphs: One of the strange conclusions of QM theory is the "Schrödinger's cat" effect. Certain properties of a particle, such as their position, speed of motion, direction of motion, and "spin", cannot be talked about until something measures them (a photon bouncing off of an electron would count as a measurement of its position, for example). Before the measurement, the particle is in a "superposition of states," in which its properties have many values at the same time. Schrödinger said that quantum mechanics seemed to say that if something (such as the life or death of a cat) was determined by a quantum event, then its state would be determined by the state that resulted from the quantum event, but only at the time that somebody looked at the state of the quantum event. In the time before the state of the quantum event is looked at, perhaps "the living and dead cat (pardon

paragraphs: the expression) [are] mixed or smeared out in equal parts."

paragraphs: People often use the symbol formula_4, which is called "h-bar." formula_5 . H-bar is a unit of angular momentum. When this new unit is used to describe the orbits of electrons in atoms, the angular momentum of any electron in orbit is always a whole number.

paragraphs: The particle in a 1-dimensional well is the most simple example showing that the energy of a particle can only have specific values. The energy is said to be "quantized."

paragraphs: The well has zero potential energy inside a range and has infinite potential energy everywhere outside that range. For the 1-dimensional case in the formula_6 direction, the time-independent Schrödinger equation can be written as:

paragraphs: Using differential equations, we can see that formula_8 must be

paragraphs: The walls of the box mean that the wavefunction must have a special form. The wavefunction of the particle must be zero anytime the walls are infinitely tall. At each wall:

paragraphs: We can see that formula_17 must be an integer. This means that the particle can only have special energy values and cannot have the energy values in between. This is an example of energy "quantization."


title: Duisburg

paragraphs: Duisburg is a German city in the state of North Rhine-Westphalia. It is where the Rhine and the Ruhr rivers meet. About 500,000 people live in Duisburg.


title: Kuopio

paragraphs: Kuopio is a city in Northern Savonia, Finland. It is the biggest city and cultural center of Eastern Finland. In November 2015 the population was about 112.000. It is the 8th biggest city in Finland.

paragraphs: The city is surrounded by lake Kallavesi. Many parts of the city are built on islands. Kuopio has always been a city of education. Two important schools are the University of Eastern Finland and the Savonia University of Applied Sciences.

paragraphs: In 2011 the town of Karttula merged with Kuopio. In 2013 Nilsiä merged as well.


title: Hammer

paragraphs: A hammer is a tool for putting nails into objects such as wood. It has a long handle, and a tip with a flat end for hitting nails. The most common type of hammer (sometimes called a "claw hammer") has a curved end (on the other side of the hitting end) for pulling nails out.

paragraphs: A sledgehammer is a hammer that has a longer shaft, and a more massive head. The user can swing it with two hands and apply more force.

paragraphs: Hammers were used around 3.3 million years ago. The first hammers were made without handles. Stones attached to sticks with strips of leather or animal sinew were being used. Hammers with handles were made in 30,000 BCE during the middle of the Paleolithic Stone Age. The hammer was used for building, food and protection.

paragraphs: Hammers can be classified into two. They are:

paragraphs: Hand-powered hammers are hammers that are used with the hand. Examples include:

paragraphs: Mechanically-powered hammers are hammers that are used with a machine. Examples include:

paragraphs: Big hammers were sometimes used as weapons. A tiny hammer is also used inside most small arms.


title: Feces

paragraphs: Feces (or faeces), also called poo, poop, shit, turd, stool, or number 2 is the body's solid waste left over from eating food. Human feces leave the intestinal tract and are removed from the body through the anus. Feces are known for their unpleasant odor. The color, which can range from dark green through brown (the most common color) to bright yellow, depends on a lot of different things; for example, different foods can change the color of feces, as can some illnesses, like diarrhea. The consistency of feces changes too. In humans it is measured using the Bristol stool scale, a system for separating feces into 7 different types. It is used for medical diagnosis.

paragraphs: Although feces are generally considered waste, they actually have many uses. Feces are used by some scientists to follow animal populations. Feces from animals and humans can be used to create fertilizers for plant crops. Some feces are also used as a fuel for fires.

paragraphs: In informal language, there are many words for feces. These are often offensive or even vulgar. Examples include "shit", "poop", and "crap".


title: Catholicism

paragraphs: Catholicism is the traditions and beliefs of Catholic Churches. It refers to their theology, liturgy, morals and spirituality. The term usually refers to churches, both western and eastern, that are in full communion with the Holy See.

paragraphs: In 2012, there were more than 1.1 billion Catholics worldwide. This makes up more than 17% of the world population.

paragraphs: The word "Catholicism" comes from the Greek word "catholikismos" (). This means "according to the whole".

paragraphs: The word "Catholicism" refers to many things, including its religious beliefs (called "theologies" and "doctrines"), and its form of religious worship (called liturgies). The word also refers to Catholic religious beliefs about ethics (things that are right and wrong). It also refers to the ways that members of the Catholic religion live and practice their religion.

paragraphs: Many people use the word "Catholicism " to talk about religious beliefs of the Catholic Church, whose leader is called the "Bishop of Rome" and often called the "Pope". The Catholic Church is based in the Vatican City, a small independent country in the city of Rome, Italy. Sometimes the word also refers to beliefs of other Christian churches, including the Eastern Orthodox Churches, who have many beliefs similar to the Catholic Church, but do not believe the Bishop of Rome is their leader.

paragraphs: The word "Catholicism" is often used to tell the difference between the beliefs of Catholic Christians and the beliefs of others called Protestant Christians. Catholic and Orthodox churches use church leaders, called bishops, to determine beliefs. Protestants, however, often use each member's own understanding of the Bible to determine beliefs. Protestants use guidelines from the 16th-century Protestant Reformation to understand the Bible. It is the world's second largest religious denomination after Sunnism.

paragraphs: The oldest document that uses the name "Catholic Church" is a letter written by a man named Ignatius. Ignatius lived in the ancient city of Antioch. In the year 107, Ignatius wrote a letter addressed to the Christian community in the ancient city of Smyrna. In this letter, Ignatius encouraged the Christian Community to be loyal to their leader, the Bishop. Ignatius wrote:

paragraphs: "Wherever the bishop shall appear, there let the multitude of the people also be; even as, wherever Jesus Christ is, there is the Catholic Church."

paragraphs: Many different denominations (groups) of Christians call themselves "catholic". Often these groups have special beliefs about their leaders, called bishops. They believe Jesus of Nazareth (whom Christians believe is the Son of God) appointed the first bishops, who appointed future bishops, who eventually appointed each community's current bishops. This appointing of leaders is called "Apostolic Succession".

paragraphs: The groups that use the term "Catholic" to talk about themselves are the:

paragraphs: Not all communities believe that other communities use the term "catholic" properly. Also, not all communities believe that the other communities have apostolic succession either. For example, the Catholic Church believes that the Eastern Orthodox have apostolic succession. However, the Catholic Church does not believe that the Anglicans or Lutherans have it.

paragraphs: Eastern Orthodox have similar beliefs about Anglicans and Lutherans. Not all Eastern Orthodox believe that the Catholic Church has apostolic succession. Different members of the Eastern Orthodox churches have different opinions.

paragraphs: However, the Anglicans and Lutherans generally believe that all Christians are part of the "catholic" church. These groups have a very different understanding of the term "Catholic".

paragraphs: Catholicism was started as a result of Jesus of Nazareth, a Jewish man whom Christians believe is the Son of God, a Christian belief known as the Trinity (Father, Son, and Holy Spirit). Catholics believe Jesus to be a descendant of David, a Jewish king from a long time ago. Jesus was crucified by the Romans in the year 33 AD. Catholics believe Jesus rose from the dead, and spoke to his followers, called the twelve Apostles. They also believe that Jesus rose into Heaven, and then sent the Holy Spirit to guide his followers at an event known as Pentecost.

paragraphs: One of his followers, the apostle named Saint Peter, was appointed leader by Jesus and later became recognized as the first Pope, or Bishop of Rome, soon after that he was captured and was martyred in Rome. Catholics believe that Saint Peter was given the "keys of the Kingdom of Heaven," meaning that Jesus made him and the apostles in charge of forgiving sins. Catholics believe that Saint Peter passed the Apostolic Power (the ability to ordain priests and consecrate the Eucharist), given to him by Christ, to the Popes, who continue to pass the power through the papacy to this day. At the current time, the pope is Pope Francis, who is the leader of the Catholic Church. The word "pope" comes from the Latin word for "father."

paragraphs: In 325, the First Council of Nicaea agreed on how to organize the church. The council agreed the Church had five patriarchs (patriarch was the highest type of church leader). The five leaders were the archbishops of Rome (the Pope), Alexandria, Antioch, Constantinople, and Jerusalem. The Patriarch of Rome, was honored as "first among equals."

paragraphs: In time, several groups split off from the Catholic Church because of differing opinions of theology. This caused breaks from the Church called schisms. Most schisms happened because people had different beliefs about what is true.

paragraphs: In 451, a church division happened when all the church leaders meeting at the Church Council in the city of Chalcedon excommunicated (cut off) three leaders, because they held to monophysitism and would not accept the view that Jesus had two natures (fully divine and fully human). These three were the bishops of Egypt, Syria, and Armenia. Of course, these three bishops did not accept being excommunicated either, so the churches under them are still known today as Oriental Orthodox Churches.

paragraphs: In 1054, an Eastern part of the Catholic Church severed itself, in the East-West Schism. The church in Western Europe which followed the Pope, became known as the Roman Catholic Church. The churches in the rest of the world, which did not think that the Pope should lead all Christians, became known as the Orthodox Church. "Orthodox" means "correct belief;" as they believe that they have kept the teachings of the early church, and the Roman Catholics have not.

paragraphs: The next big secession was the Protestant Reformation. Protestants resisted the valid central authority of the Church in Rome and rejected many practices, beliefs and disciplines. The Reformation started in Germany, where Martin Luther sent his demands for change to the Church. Because of politics in Europe, many nations supported Luther. The Lutheran Church was started. Later the Calvinist or Presbyterian Church started.

paragraphs: In England, King Henry VIII started the Anglican church. He wanted to divorce his first wife; but the Pope wouldn't allow it, as the marriage was valid. At first, the church of King Henry VIII, the Church of England, was very similar to the Catholic Church. The major difference was that the king was head of the church, instead of the Pope. Later, under his son, Edward VI, the Anglican Church became more reformed or Protestant. Anglicans, and several other Protestant denominations, still believe they are reformed Catholics. Puritanism arose among Anglicans who thought the reforms didn't go far enough.

paragraphs: After the Reformation, many other Churches began because of disagreements over beliefs and practices of earlier Protestant doctrine. According to the 2010 U.S. Religious Congregations and Membership Study, this accounts for most of the Protestant denominations in the United States. There are about 314,000 of these. Two examples of these Protestant (or Reformed) churches are Methodist and Baptist.


title: Nail

paragraphs: A nail is a metal object with a flat head and a long, sharp tip. A hammer or nail gun is used to put it into another object. It is often used to join two objects together.

paragraphs: The history of the nail came in three periods:

paragraphs: Nails date back at least to Ancient Egypt – bronze nails found in Egypt have been dated 3400 BC. The Bible has references to nails. King David gave iron to make nails for what would become Solomon's Temple.

paragraphs: The Romans made extensive use of nails. The Roman army left behind seven tons of nails when it evacuated the fortress of Inchtuthil in Perthshire, Scotland, in 86 or 87 AD.


title: Dictatorship

paragraphs: A dictatorship is a form of government where one person or political party has the power to do whatever they want. The ruler is called a dictator. In a dictatorship, the individuals rights are usually suppressed.

paragraphs: Dictators often come to power in times of difficulty, such as massive unemployment, inflation, and unrest among the population. Dictators are normally backed by powerful groups, such as landowners, private company owners, bank owners and in some cases institutions like the Roman Catholic Church to put in place law and order by force. This force may be directed at the poorer parts of society, such as unemployed workers, ethnic minorities, working class areas andshanty towns. Examples of this are the dictatorships in Latin America and the prosecution of the Jewish community in 1940s Germany.

paragraphs: Dictators normally need to do a number of things to put in place their dictatorships: they need to get rid of their opponents (which may be political or religious) - some are imprisoned, exiled (sent outside their country) or killed. Dictators will then need to prohibit (or not allow) political parties that oppose their rule. They will confiscate the political parties' property or offices and such things. Dictators may suppress or persecute some religious groups or institutions. Dictators will also need to undo or close down democratic institutions such as parliament and in some cases the congress. Some social organizations, such as civil rights groups, human rights organisations, legal aid centers, students' unions, teachers' federations, trade or workers unions are also undone and those who persist with such activities may be killed. Dictators will normally rewrite an existing constitution or put in place a completely new one. This makes their power constitutional (which then cannot be disputed). Dictators then maintain their rule with state terrorism, which normally involves a secret police, death squads, random or night curfew, indefinite arrest without trial and a network of torture centers and concentration camps. Some dictatorships create a fictional (or non existent) internal (inside their country) enemy which they claim to be at war with to justify (give reason for) their use of much military violence against a whole unarmed population.

paragraphs: A dictatorship that is ruled by soldiers is called a military dictatorship or junta. An absolute monarchy (the system where there are Kings and Queens who have full power over their country) can be considered to be a dictatorship, but are usually not called dictators. A dictatorship is usually not liked by the people, because most don't like to be dictated around. Most dictators are selfish and rule over the people just for power.


title: Electricity

paragraphs: Electricity is the presence and flow of electric charge. Using electricity we can transfer energy in ways that allow us to do simple chores. Its best-known form is the flow of electrons through conductors such as copper wires.

paragraphs: The word "electricity" is sometimes used to mean "electrical energy". They are not the same thing: electricity is a transmission medium for electrical energy, like sea water is a transmission medium for wave energy. An item which allows electricity to move through it is called a conductor. Copper wires and other metal items are good conductors, allowing electricity to move through them and transmit electrical energy. Plastic is a bad conductor (also called an insulator) and does not allow much electricity to move through it so it will stop the transmission of electrical energy.

paragraphs: Transmission of electrical energy can happen naturally (such as lightning), or be made by people (such as in a generator). It can be used to power machines and electrical devices. When electrical charges are not moving, electricity is called static electricity. When the charges are moving they are an electric current, sometimes called 'dynamic electricity'. Lightning is the most known - and dangerous - kind of electric current in nature, but sometimes static electricity causes things to stick together in nature as well.

paragraphs: Electricity can be dangerous, especially around water because water is a form of good conductor as it has impurities like salt in it. Salt can help electricity flow. Since the nineteenth century, electricity has been used in every part of our lives. Until then, it was just a curiosity seen in the lightning of a thunderstorm.

paragraphs: Electrical energy can be created if a magnet passes close to a metal wire. This is the method used by a generator. The biggest generators are in power stations. Electrical energy can also be released by combining chemicals in a jar with two different kinds of metal rods. This is the method used in a battery. Static electricity can be created through the friction between two materials - for instance a wool cap and a plastic ruler. This may make a spark. Electrical energy can also be created using energy from the sun, as in photovoltaic cells.

paragraphs: Electrical energy arrives at homes through wires from the places where it is made. It is used by electric lamps, electric heaters, etc. Many appliances such as washing machines and electric cookers use electricity. In factories, electrical energy powers machines. People who deal with electricity and electrical devices in our homes and factories are called "electricians".

paragraphs: There are two types of electric charges that push and pull on each other: positive charges and negative charges. Electric charges push or pull on each other if they are not touching. This is possible because each charge makes an electric field around itself. An electric field is an area that surrounds a charge. At each point near a charge, the electric field points in a certain direction. If a positive charge is put at that point, it will be pushed in that direction. If a negative charge is put at that point, it will be pushed in the exact opposite direction.

paragraphs: It works like magnets, and in fact, electricity creates a magnetic field, in which similar charges repel each other and opposite charges attract. This means that if you put two negatives close together and let them go, they would move apart. The same is true for two positive charges. But if you put a positive charge and a negative charge close together, they would pull towards each other. A short way to remember this is the phrase opposites attract likes repel.

paragraphs: All the matter in the universe is made of tiny particles with positive, negative or neutral charges. The positive charges are called protons, and the negative charges are called electrons. Protons are much heavier than electrons, but they both have the same amount of electric charge, except that protons are positive and electrons are negative. Because "opposites attract," protons and electrons stick together. A few protons and electrons can form bigger particles called atoms and molecules. Atoms and molecules are still very tiny. They are too small to see. Any big object, like your finger, has more atoms and molecules in it than anyone can count. We can only estimate how many there are.

paragraphs: Because negative electrons and positive protons stick together to make big objects, all big objects that we can see and feel are electrically neutral. "Electrically" is a word meaning "describing electricity", and "neutral" is a word meaning "balanced." That is why we do not feel objects pushing and pulling on us from a distance, as they would if everything was electrically charged. All big objects are electrically neutral because there is the same amount of positive and negative charge in the world. We could say that the world is exactly balanced, or neutral. Scientists still do not know why this is so.

paragraphs: The electrons can move all around the material. Protons never move around a solid object because they are so heavy, at least compared to the electrons. A material that lets electrons move around is called a conductor. A material that keeps each electron tightly in place is called an insulator. Examples of conductors are copper, aluminum, silver, and gold. Examples of insulators are rubber, plastic, and wood. Copper is used very often as a conductor because it is a very good conductor and there is so much of it in the world. Copper is found in electrical wires. But sometimes, other materials are used.

paragraphs: Inside a conductor, electrons bounce around, but they do not keep going in one direction for long. If an electric field is set up inside the conductor, the electrons will all start to move in the direction opposite to the direction the field is pointing (because electrons are negatively charged). A battery can make an electric field inside a conductor. If both ends of a piece of wire are connected to the two ends of a battery (called the "electrodes"), the loop that was made is called an electrical circuit. Electrons will flow around and around the circuit as long as the battery is making an electric field inside the wire. This flow of electrons around the circuit is called electric current.

paragraphs: A conducting wire used to carry electric current is often wrapped in an insulator such as rubber. This is because wires that carry current are very dangerous. If a person or an animal touched a bare wire carrying current, they could get hurt or even die depending on how strong the current was and how much electrical energy the current is transmitting. You should be careful around electrical sockets and bare wires that might be carrying current.

paragraphs: It is possible to connect an electrical device to a circuit so that electrical current will flow through a device. This current will transmit electrical energy to make the device do something that we want it to do. Electrical devices can be very simple. For example, in a light bulb, current carries energy through a special wire called a filament, which makes it glow. Electrical devices can also be very complicated. Electrical energy can be used to drive an electric motor inside a tool like a drill or a pencil sharpener. Electrical energy is also used to power modern electronic devices, including telephones, computers, and televisions.

paragraphs: Here are a few terms that a person can come across when studying how electricity works. The study of electricity and how it makes electrical circuits possible is called electronics. There is a field of engineering called electrical engineering, where people come up with new things using electricity. All of these terms are important for them to know.

paragraphs: Electrical energy is mostly generated in places called power stations. Most power stations use heat to boil water into steam which turns a steam engine. The steam engine's turbine turns a machine called a 'generator'. Coiled wires inside the generator are made to spin in a magnetic field. This causes electricity to flow through the wires, carrying electrical energy. This process is called electromagnetic induction. Michael Faraday discovered how to do this.

paragraphs: There are many sources of heat which can be used to generate electrical energy. Heat sources can be classified into two types: renewable energy resources in which the supply of heat energy never runs out and non-renewable energy resources in which the supply will be eventually used up.

paragraphs: Sometimes a natural flow, such as wind power or water power, can be used directly to turn a generator so no heat is needed.


title: Sailor Moon

paragraphs: Pretty Soldier Sailor Moon or Sailor Moon is a shojo manga by Naoko Takeuchi. It was adapted to an anime series by Toei Animation CO., LTD. "Sailor Moon" was one of the most popular anime/manga series during the 1990s, spanning five seasons, four movies, and multiple video games. It continues to hold a strong fanbase with many fansites devoted to it.

paragraphs: Usagi (Serena in English) is an eighth grader who is clumsy, a crybaby and who also gets bad grades. One day, she meets a talking cat named Luna, who tells her that she is Sailor Moon, a superhero. She has to fight monsters to save people from getting their energy stolen by evil beings. Usagi has some friends who fight evil along with her. They are named Sailor Mercury, Sailor Venus, Sailor Mars, and Sailor Jupiter. They make up a team called the Sailor Senshi ("Senshi" means "soldier" or "guardian in Japanese"). The Sailor Senshi are named after different planets in the solar system. Each of the Sailor Senshi uses magical powers to become a Sailor Senshi. They are also young Japanese girls. Their real names are not Sailor Mercury, Sailor Venus, Sailor Mars, and Sailor Jupiter. For example, when Sailor Mercury is not fighting evil, her name is Ami Mizuno (Amy in English). The name of Sailor Venus is Minako Aino (Mina in English). The name of Sailor Mars is Rei Hino (Raye in English). The name of Sailor Jupiter is Makoto Kino (Lita in English). Each of them has a transformation sequence where they turn into their Sailor Senshi form, with many colourful effects.

paragraphs: Mamoru Chiba (called Darien Chiba in the English manga and Darien Shields in the English anime) is Usagi's boyfriend. He uses magic powers to transform into a man named Tuxedo Mask, who fights evil along with the Sailor Senshi. In the future, Usagi and Mamoru get married and become the king and queen of the earth. Their daughter, named Chibiusa (Rini in the English version), travels through time to help them and the Sailor Senshi.

paragraphs: Usagi has a cat named Luna, named after the Latin word for moon. Minako has a cat named Artemis after the Greek goddess of the moon (although Artemis is a male cat). Luna and Artemis are not ordinary cats. They can talk, and they have moon symbols on their foreheads. They can also turn into humans in the manga, and Luna turns into a human in one of the anime movies. In the future, they have a kitten named Diana (Diana is the name of the Roman moon goddess).

paragraphs: Later on there are some other Sailor Senshi. They are named after the planets Saturn, Uranus, Neptune, and Pluto (now a dwarf planet). Sailor Saturn's real name is Hotaru Tomoe. Sailor Uranus' real name is Haruka Tenoh (Amara in English). Sailor Neptune's real name is Michiru Kaioh (Michelle in English). Sailor Pluto's real name is Setsuna Meioh (Trista in English). In the manga and anime series, Haruka and Michiru are lesbians, but in the English anime they were changed to cousins. This is because the English anime was made for younger children than the anime series.

paragraphs: Each Sailor Senshi has different powers. Sailor Moon has powers of love and healing. Sailor Mercury has powers of water and ice. Sailor Mars has fire powers, Sailor Jupiter has electricity and plant powers, and Sailor Venus has light and energy powers. Sailor Chibi Moon, (called Sailor Mini Moon in the English version) has love and sugar powers. Sailor Saturn is death and rebirth, Sailor Neptune is water, Sailor Uranus is earth, and Sailor Pluto has time and death powers. Tuxedo Mask can throw roses against enemies.

paragraphs: In the manga there are five series: "Bishoujo Senshi Sailor Moon", "Bishoujo Senshi Sailor Moon R(eturn/omance)", "Bishoujo Senshi Sailor Moon Super" "Bishoujo Senshi Sailor Moon SuperS" "Bishoujo Senshi Sailor Moon Stars". Sailor Moon was originally serialized in the Japanese manga magazine by Kodansha. Afterwards Kodansha published the completed series in volumes. There are eighteen volumes total.

paragraphs: The anime stayed close to the story from the manga. However, due to its popularity, Toei made more seasons and produced movies. Sailor Moon was licensed to be aired in the United States by DIC Entertainment (a company that makes TV and film). DIC cut out some scenes and changed some of the dialogue to make it more acceptable for children. Many anime fans did not like the changes. Due to their complaints, ADV Films and later Pioneer Inc. made uncut versions.

paragraphs: The following TV series and movies were made:


title: Anesthetic

paragraphs: An anesthetic or anaesthetic is a substance that stops pain. It makes people either stop hurting, or go completely to sleep during surgery. Anesthetic can be rubbed onto the skin, given by injection ("shot"), or given as a gas to breathe. The use of an anesthetic is called anaesthesia. Anaesthesia blocks the pain during operations. This lets patients undergo surgery and other procedures without the distress and pain they would normally feel. It comes from Greek roots an-, "without" and aesthetos, "perceptible, able to feel".

paragraphs: The modern anesthetic was created by Joseph Lister. Before it, people sometimes used cocaine, alcohol, and other drugs. Modern anaesthesia is highly complex and often involves a combination of anaesthesia, analgesia and muscle relaxation to enable physicians to do their part. These three tasks are known as the triad of anaesthesia.


title: Fidel Castro

paragraphs: Fidel Alejandro Castro Ruz (August 13, 1926 – November 25, 2016) was a Cuban revolutionary and politician. He was Prime Minister of Cuba from 1959 to 1976, and President from 1976 to 2008. He temporarily gave power to his brother Raúl Castro while recovering from surgery in summer of 2006. On February 19, 2008, he announced that he would not return to power. He was in power for 49 years.

paragraphs: Castro was born in Birán, Cuba on August 13, 1926. He received a doctorate of law from the University of Havana. He was trained as a military lawyer. He came to power after he and his guerrilla soldiers overthrew the dictatorship of General Fulgencio Batista.

paragraphs: Castro was a communist and he made Cuba the first socialist country of the Americas. During the Cold War he was a friend of the Soviet Union, and he depended on their help until the USSR collapsed. An important moment of the Cold War was the Cuban Missile Crisis of 1962. In October 1962 the United States of America discovered that the Soviet Union was placing missiles on Cuba, close to the United States. After very tense talking, a big nuclear war was avoided between the Soviet Union and the USA.

paragraphs: Some people call Castro a dictator. They criticize him, because they think he has ignored some human rights, for example, torture, murder and oppression of freedom of speech, both at home and in African countries where he sent Cuban soldiers to spread Communism. Other people do not think this is true. For example, Nelson Mandela has spoken in support of Castro and has thanked him for aid to Africa. Amnesty International criticized Cuba's human rights record but noted slow progress in July of 2002. Supporters of Castro say he gave Cuba the best health care and education of Latin America and created equality between the poor and the rich.

paragraphs: Castro's first wife was Mirta Díaz - Balart. They married in October 1948. They had a son Fidel Ángel "Fidelito" Castro Díaz-Balart, born in September 1949. Díaz-Balart and Castro divorced in 1955. In 1980, Castro married Dalia Soto del Valle. Their marriage would end with Castro's death in 2016.

paragraphs: On November 25, 2016, Castro died at age 90 of natural causes in Havana, Cuba. President Raúl Castro, his brother, announced Fidel's death on state television. His remains were later cremated on November 26, 2016.


title: Latin America

paragraphs: Latin America is a region of the Americas consisting of countries where the people speak Romance languages (languages that came from Vulgar Latin).

paragraphs: People do not completely agree as to which countries are in Latin America, but in most cases, it is made up of the parts where Spanish and Portuguese are spoken. This includes most of South America and Central America (sometimes also the Caribbean islands), and also Mexico in North America.

paragraphs: Others consider the places in the Americas (except those in Canada and the United States) which speak French to be part of Latin America, because it is also a Romance language.

paragraphs: The following is a list of the ten largest metropolitan areas in Latin America.

paragraphs: People in Latin America are part of several ethnic groups and races. The majority of Latin Americans are Mestizo and some others are Mulatto, Black, Zambo, and Asian.

paragraphs: Most of these ethnic groups can be found anywhere in Latin America; but since most Latin Americans are of mixed-race, many of these ethnic groups do not reach 100%.

paragraphs: Spanish and Portuguese are the most common languages in Latin America. Portuguese is the official language of Brazil, while Spanish is the official language of most other Latin America mainland countries, and of Cuba, Puerto Rico (along with English), and the Dominican Republic.

paragraphs: Many people speak Native American languages in Peru, Guatemala, Bolivia, Paraguay and Mexico. These languages are less common in other countries, but in some countries like Bolivia, they are considered official along with the main European language.

paragraphs: Other Indo-European languages spoken in Latin America include English (mainly in Puerto Rico but also in Guyana), French (spoken in Haiti and French Guiana), and Dutch (in Suriname). Although French is also spoken in the Canadian province of Quebec and the American state of Louisiana, these countries are not considered part of Latin America because they are mostly English-speaking. Guyana, French Guiana (one of the overseas territories of France), and Suriname, which are found the northern part of South America and known together as the Guianas, are the only places in South America that do not speak Spanish or Portuguese.

paragraphs: Some African languages are also spoken in Latin America. The west African Yoruba language (known as Lucumi) is spoken in Cuba, where it is a ritual language used by the Santeria prayers.

paragraphs: In several nations, Creole languages are also spoken, especially in the Caribbean. Palenquero is the Spanish-based Creole language spoken in Colombia by some 3,000 people, it is Spanish with many African influences and some Portuguese influence. Other creoles in mainland Latin America have the same roots, blending Spanish with either African or Indigenous languages or both, as Cuban Spanish does. The island of Haiti also has a well-known creole language, called Haitian Creole.

paragraphs: Most Latin Americans are Christians. A 2014 survey found that 69% of Latin Americans are Roman Catholic, while 17% are Protestants. Most Protestants are from Brazil or Central America.

paragraphs: Poverty continues to be one of the biggest challenges for Latin American countries. According to estimates, Latin America is the most unequal region of the world. According to a Country Studies Institute the poorest countries in the region (in 2011) were: Haiti, Nicaragua, Bolivia and Honduras. Undernourishment affects 72% of Haitians, 47% of Nicaraguans and Bolivians, and 32% of Hondurans.

paragraphs: Also, according to the Country Studies Institute, over 90% of Haitians, 75% of Bolivians, 70% of Nicaraguans, and 63% of Hondurans live in poverty.


title: Washington, D.C.

paragraphs: Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district. The President of the USA and many major national government offices are in the territory. This makes it the political center of the United States of America.

paragraphs: Washington was named after the first U.S. President George Washington. "D.C." stands for "District of Columbia". At first, it was made up of a piece from Virginia south of the Potomac River and a piece from Maryland north of the Potomac River. In 1847, Virginia's piece was returned to it, and is now Arlington County and part of the city of Alexandria. Since 1847, all of the District of Columbia is on the north side of the Potomac River. The District of Columbia used to have other small towns which used "D.C.".

paragraphs: Since 1800, The District of Columbia has been the home of all three branches of the U.S. government: Congress, the President, and the Supreme Court. All of the major political parties are based here. It is also the headquarters of the World Bank, the International Monetary Fund (IMF), and the Organization of American States (OAS). Because it is the home of the President and is important to American politics, many groups often hold large demonstrations and protests here. These are often at the National Mall, a large open park which has many monuments and museums. The District of Columbia’s many museums and monuments make it a popular place for tourists to visit.

paragraphs: In 2005, the United States Census Bureau showed that 582,049 people resided within the District of Columbia.

paragraphs: The city is considered a black mecca and has a large African American population.

paragraphs: When English people first came to the area, there was a Native American village on the spot called "Nakochtank". This name survives in the name of the Anacostia River. This river was known for the healing properties of its pure water and it is recorded that the Emperor Powhatan, who lived in what is now Richmond, Virginia, made the trip all the way to Nakochtank once for this reason.

paragraphs: The 1789 United States Constitution said that a capital city would be created in a district, but did not say where it should be. James Madison and others thought it should be far away from other states and cities. This way, it would be independent and not controlled by any state. In 1790, a compromise was reached and capital was placed between Virginia and Maryland. It was a square, ten miles (16 km) long on each side, and split by the Potomac River, which separated the two states. Half of the district was in Maryland and the other half was in Virginia, and the two states gave this land to the government. In 1791, it was named "Washington, the District of Columbia" to honor George Washington. "Columbia" was another name for North America.

paragraphs: Washington, D.C. was planned before it was built. Pierre L'Enfant drew a plan for the city that said where all the streets, parks, and important buildings would be. Unlike most cities in the United States, D.C. has many roundabouts or traffic circles. The city was supposed to have long and wide avenues, and many open spaces for monuments and parks. The National Mall is an example of this.

paragraphs: Washington, D.C. is not a state. Its citizens have less control over their city than most Americans, but D.C. has had an elected mayor and a city council since 1973. But Congress can make it so that a local law doesn't happen. The current mayor of Washington, D.C. is Muriel Bowser, a Democrat.

paragraphs: The license plates on the cars in Washington, D.C. say, "Taxation Without Representation." This is a protest from people who live in Washington, D.C. about having to pay taxes to the United States without having a vote in the United States House of Representatives. It resembles the protest made by colonists before the American Revolution about having to pay taxes to Great Britain. Some people are against letting Washington, D.C. have a Congressman or Congresswoman because the Constitution only allows states to have Congressmen or Congresswomen.

paragraphs: Washington, D.C. is the center of the nation for its arts. The National Symphony Orchestra, the Washington National Opera, and the Washington Ballet are all inside the John F. Kennedy Center for the Performing Arts. The Kennedy Center Honors are given every year to the people who have greatly helped the cultural life of the United States. The President and First Lady usually go to the Honors ceremony.

paragraphs: As the national capital of the United States, Washington, D.C. has numerous media outlets in various mediums. Some of these media are known throughout the United States, including "The Washington Post" and various broadcasting networks headquartered in D.C.

paragraphs: "The Washington Post" is the oldest and most-read daily newspaper in Washington, and it has developed into one of the most reputable daily newspapers in the U.S. It is most notable for exposing the Watergate scandal, among other achievements. The Washington Post Company has multiple media holdings, including a daily free newspaper called the "Express", the Washington Post News Service with Bloomberg News, "Fashion Washington", "El Tiempo Latino" (a Spanish-language publication), the Slate Group, "The Daily Herald" (in Washington state), as well as the education company Kaplan, Inc. "The Washington Post" emphasizes national and political news coverage but also covers regional and local stories. Headquartered in downtown Washington, the newspaper employs journalists at 11 regional bureaus in Maryland and Virginia and 14 international bureaus. Content is shared across titles within the Washington Post Company, and the "Express", in particular, often reprints content from the Associated Press, Getty Images, and other wire sources.

paragraphs: "Washington Times" and "Washington City Paper" also have substantial readership in the District. On February 1, 2005, the free daily tabloid "Washington Examiner" debuted, having been formed from a chain of suburban newspapers known as the "Journal Newspapers".

paragraphs: "Washington Blade" and "Metro Weekly" focus on gay issues and the "Washington Sun", the "Washington Informer", and also "Washington Afro" on African American issues. Bi-weekly "Street Sense" focuses on issues of homelessness poverty, and life on the streets. Other special-interest papers include "Roll Call", a daily paper focused on politics.

paragraphs: Many neighborhoods in the District have their own community newspapers. Some of these include "The Current Newspapers", which has editions serving Dupont Circle, Foggy Bottom, Georgetown, Chevy Chase and Upper Northwest, and a Capitol Hill paper called "The Capitol Hill Current/Voice of the Hill". Additional papers include "In-Towner" (Dupont Circle, Logan Circle and Adams Morgan), "Hill Rag" (Capitol Hill), "East of the River" (Anacostia) and "D.C. North" (Northeast D.C.). In addition, several specialty newspapers serve the U.S. Congress; most notable are "Roll Call", "The Hill", and "Politico".

paragraphs: As of 2008, the Washington Metropolitan Area was the 9th largest designated market area in the United States, with 2,321,610 television homes (2.028% of the U.S. population). The following is a list of television stations serving the metro area:

paragraphs: Most Baltimore area television stations can be seen in the Washington region. Besides being viewed clearly in the District, they can especially be seen in the suburbs of the Interstate 95 corridor between both cities. They are: WMAR 2 (ABC), WBAL 11 (NBC), WJZ 13 (CBS), WMPT 22 / WMPB 67 (PBS/MPB), WUTB 24 (MyNetwork TV), WBFF 45 (FOX), and WNUV 54 (The CW). A DC-MD-VA regional news station, TBD TV, is carried on Channel 8 on all cable systems in Washington, D.C. and surrounding communities.

paragraphs: Public, educational, and government access (PEG) on cable television is provided by the Public Access Corporation of the District of Columbia on two channels simulcast to both local cable television systems. One channel is devoted to religious programming and the other channel provides a diversity of offerings. The District's two Public, educational, and government access (PEG) Channels are DCTV, a non-profit media outlet that provides training and production opportunities to local residents, and OCT TV-16, which provides information about government programs, services, and related opportunities.

paragraphs: Major national broadcasters and cable outlets including NBC, ABC, CBS, FOX, and CNN maintain a significant presence in Washington, as do those from around the world including the BBC, CBC, and Al Jazeera. The Public Broadcasting Service (PBS) is headquartered in Arlington, Virginia. Also, several cable television networks have their headquarters in the Washington area, including:

paragraphs: America's Most Wanted is the only network primetime program produced in Washington.

paragraphs: As of 2008, the Washington Metropolitan Area was the 9th largest radio market in the United States with a Metro 12+ Population of 4,238,100. The following is a list of radio stations serving the metro area:

paragraphs: According to a 2010 study, Washington-area commuters spent 70 hours a year in traffic delays, which tied with Chicago for having the nation's worst road congestion. However, 37% of Washington-area commuters take public transportation to work, the second-highest rate in the country. An additional 12% of D.C. commuters walked to work, 6% carpooled, and 3% traveled by bicycle in 2010.

paragraphs: Washington has very few freeways. The funds that had been dedicated for freeway construction were instead redirected to the region's public transportation infrastructure. The interstate highways that do continue into Washington, including Interstate 66 and Interstate 395, both terminate shortly upon entering the city.

paragraphs: The Washington Metropolitan Area Transit Authority (WMATA) operates the Washington Metro, the city's rapid transit system, as well as Metrobus. Both systems serve the District and its suburbs. Metro opened on March 27, 1976 and presently consists of 86 stations and of track. With an average of about one million trips each weekday, Metro is the second-busiest rapid transit system in the country, after the New York City Subway. Metrobus serves over 400,000 riders each weekday, making it the nation's sixth-largest bus system. The city also operates its own DC Circulator bus system, which connects commercial areas within central Washington.

paragraphs: Union Station is the main train station in Washington, D.C., and handles about 70,000 people each day. It is Amtrak's second-busiest station with 4.6 million passengers annually and serves as the southern terminus for the Northeast Corridor and Acela Express routes. Maryland's MARC and Virginia's VRE commuter trains and the Metrorail Red Line also provide service into Union Station. Expansion plans announced in 2011 will make Union Station the city's primary intercity bus transit center. A new streetcar system opened in 2016.

paragraphs: Three major airports serve The District. The Ronald Reagan Washington National Airport is across from downtown Washington in Arlington, Virginia and has its own Metrorail station. Major international flights arrive and depart from Washington Dulles International Airport, west of the District in Fairfax and Loudoun counties in Virginia. Dulles gained its own Metrorail station in 2016. Baltimore/Washington International Thurgood Marshall Airport is northeast of the District in Anne Arundel County, Maryland.


title: President of the United States

paragraphs: The president of the United States of America (often shortened to POTUS) is the head of government and chief executive of the United States. The office of president was created in the United States Constitution in 1788. The first president (George Washington) took office in 1789. The president is in charge of the executive branch of the United States government. The United States Constitution makes the president the Commander-in-Chief of the armed forces. It also lists powers given to the President, though these powers have been expanded through practice over time.

paragraphs: On November 9, 2016, Donald Trump was elected to be the 45th president of the United States, not including Grover Clevlend's second non-consecutive term. Grover Cleveland served two non-consecutive terms in office, and is counted as the nation's 22nd and 24th president. Thus the incumbent, Donald Trump, is the nation's 45th president. There are currently four living former presidents. The most recent death of a former president was on November 30, 2018 with the death of George H. W. Bush; the most recently serving president to die was also George H. W. Bush on November 30, 2018. The current president was formally inaugurated on January 20, 2017, succeeding Barack Obama.

paragraphs: of the Constitution sets the requirements to hold office. A president must:

paragraphs: The president is indirectly elected by the people through the Electoral College to a four-year term, and is one of only two nationally elected federal officers, the other being the Vice President of the United States. A president must receive more than 270 electoral college votes in order to win an election. Ronald Reagan received 525 votes which is the most electoral votes of any other president.

paragraphs: A president can only serve two terms as president, which is eight years. Franklin D. Roosevelt served four terms as president. He died shortly after beginning his fourth term. After his death, congress passed an amendment which limits the number of terms a president can have.

paragraphs: William Henry Harrison served the shortest term, one month, because he died in office from pneumonia.

paragraphs: A president officially becomes president after being inaugurated on January 20th. The president must be given the oath of office by the Chief Justice of the United States. It is traditionally held at the United States Capitol.

paragraphs: With the agreement of the United States Senate he or she can:

paragraphs: If the president dies or retires between elections, or is otherwise removed from office, the Acting President will become president, who is usually the Vice President.

paragraphs: Abraham Lincoln, James A. Garfield, William McKinley, and John F. Kennedy were assassinated while in office. William Henry Harrison, Zachary Taylor, Warren G. Harding, and Franklin Roosevelt died from illness while president. John Tyler was the first Vice President of the United States to become president.

paragraphs: Gerald Ford, Richard Nixon's vice president, became president after Nixon resigned. Nixon is the only president to have resigned.

paragraphs: Andrew Johnson, Bill Clinton and Donald Trump are the only presidents to have been impeached.

paragraphs: A president travels by either traveling on Air Force One, Marine One, or by the Presidential state car. At all times, the president is protected by Secret Service agents. Sometimes, the president may travel to Camp David for either relaxation or to do some work in peace.

paragraphs: By a majority of historical sources by historians or by the American people; George Washington, Thomas Jefferson, Abraham Lincoln, Woodrow Wilson, Franklin D. Roosevelt, Harry S. Truman, Dwight D. Eisenhower, John F. Kennedy, Ronald Reagan, George H. W. Bush, and Bill Clinton are ranked high on polls.

paragraphs: On the other hand; James Buchanan, Warren G. Harding, Herbert Hoover, Lyndon B. Johnson, Richard Nixon, Jimmy Carter, and George W. Bush are thought to be the worst.

paragraphs: Since Herbert Hoover, each president has created a institutional place known as a presidential library for preserving and making available his papers, records and other documents and materials. There are currently thirteen presidential libraries in the NARA system.

paragraphs: There are also presidential libraries maintained by state governments and private foundations, such as the Abraham Lincoln Presidential Library and Museum, which is run by the State of Illinois.

paragraphs: Several presidential libraries contain the graves of the president such as Richard Nixon at his library in Yorba Linda, California and Ronald Reagan at his library in Simi Valley, California.


title: J. R. R. Tolkien

paragraphs: John Ronald Reuel Tolkien (3 January 1892 – 2 September 1973) was a British philologist, university professor, and writer. Tolkien is best known for his most famous works, "The Hobbit" and "The Lord of the Rings".

paragraphs: He was born in Bloemfontein, South Africa but his parents were both from England. He lost much of his family at an early age. He fought in World War I, and after the war he found a job helping to produce the Oxford English Dictionary. Tolkien was very interested in languages, and he had studied at Oxford University. Soon he became a professor of English Language at the University of Leeds. He was then a professor at the University of Oxford until 1959, when he retired. He also was good friends with many other writers and scholars, most notably C. S. Lewis, who wrote the "Narnia" books, "The Screwtape Letters", and many essays on Christian theology. Tolkien himself was a devout Catholic.

paragraphs: Tolkien married Edith Mary Bratt on 22 March 1916 in England, at the age of 24. They had four children, three sons and a girl: John, Michael, Christopher, and Priscilla.

paragraphs: He created and worked on the fictional fantasy world of Middle-earth for most of his life, and his most famous books are set in that world. Because of his Middle-earth books he is often considered the "father of high fantasy" which made the fantasy genre very popular.

paragraphs: Tolkien wrote other books, for example "Farmer Giles Of Ham", and also illustrated (drew the pictures and maps for) "The Lord of the Rings". "The Lord of the Rings" was published in three parts and has been made into several motion pictures. "The Lord of the Rings" took 12 years to write.


title: Adolescence

paragraphs: Adolescence is the time between being a child and a mature adult, that is the period of time during which a person grows into an adult, but are emotionally not mature. Adolescence in the English speaking world usually corresponds to the teenage years of 13-19 which are so named because of the end of the English words "thirteen" to "nineteen".

paragraphs: The ages when one is no longer a child, and when one becomes an adult, vary by culture. In many cultures they are marked by rites of passage. The word comes from the Latin verb "adolescere" meaning "to grow up." During this time, a person's body, emotions and academic standing change a lot. When adolescence starts, in America, children usually finish elementary school and enter secondary education, such as middle school or high school.

paragraphs: During this period of life, most children go through the physical stages of puberty, which can often begin before a person has reached the age of 13. Most cultures think of people as becoming adults at various ages of the teenage years. For example, Jewish tradition thinks that people are adults at age 13, and this change is celebrated in the Bar Mitzvah (for boys) and the Bat Mitzvah (for girls) ceremony. Usually, there is a formal age of majority when adolescents formally (under the law) become adults.


title: KDE

paragraphs: KDE is a community that produces free software, including a desktop environment called KDE Plasma for operating systems based on Linux or UNIX. This replaces the console, which is simply a black screen with text on it. KDE Plasma is a popular piece of software for users of Linux and UNIX.

paragraphs: Plasma runs on top of the X Window System, which runs on top of any UNIX-like operating systems like Linux and Mac OS X.

paragraphs: Since KDE SC 4.0, many KDE programs also runs on Microsoft Windows.

paragraphs: The following table lists when each version of KDE was released.

paragraphs: There are several major applications for KDE. These include:


title: UK Independence Party

paragraphs: The United Kingdom Independence Party (often called UKIP, said "you-kipp") is a political party in the United Kingdom. Its policies promote conservatism, national conservatism, and Euroscepticism. Their main policy is for the UK to leave the European Union.

paragraphs: The party was founded in 1993, and they first won seats in the European Parliament in 1999. They won 3 seats in 1999, which was increased to 12 in 2004 and 13 in 2009. It is now 9. The party does not do well under Britain's 'First-past-the-post' system of elections and only has one seat in the British House of Commons, although they received 3.8 million votes (12.6% of the total vote) at the 2015 UK general election.

paragraphs: Supporters of UKIP mostly believe in the following things:

paragraphs: In 2008 UKIP banned people who used to be members of the British National Party (BNP) from joining.

paragraphs: On 9 October 2014 Douglas Carswell became UKIP's first elected MP. Carswell quit the party in March 2017.

paragraphs: In the May 2014 local elections UKIP got 30% of the vote in Sunderland. The party gained 155 local council seats across the country.

paragraphs: UKIP came third in the May 2015 general election, after the Labour Party and the Conservative Party. The party got 12.9% of the vote and gained one seat.

paragraphs: In the 2017 general election, UKIP's share of the vote went down to 1.8 and they didn't win any seats. The next day UKIP's leader Paul Nuttall resigned.

paragraphs: There are currently over 20,000 people who are members of the UKIP.

paragraphs: In February 2018 Gerard Batten become leader of the party firstly on an interim basis before winning the UKIP leadership election in April 2018 unopposed.

paragraphs: In the 2018 UK local elections UKIP lost 124 of the 126 seats it was defending, and gained a single seat in Derby.

paragraphs: Since the election of Batten as leader of the party there have been accusations that UKIP is embracing the far-right. Those saying the party was moving to the right began early in Battern's leadership when he began to focus the party around rejecting Islamic ideology and when a quote arose of Battern calling Islam a "death cult". In September 2018 Battern was also criticised for attending an anti-Muslim rally in Sunderland. These accusations grew much stronger after the far-right activist Tommy Robinson was appointed an advisor to Battern in November 2018. This led to many of UKIP's MEPs and former party leaders Nigel Farage and Paul Nuttall to leave the party, as well as the party's leader in Scotland.


title: Space Oddity

paragraphs: David Bowie's first big hit record was the single "Space Oddity" in 1969. This album though only really sold well when he became more famous in 1973. Many of the songs are very melodic, with good tunes, and are unusual.


title: Saxophone

paragraphs: A saxophone is a family of musical instruments that are made of brass. These are often just called a "sax". It has seven main keys, including the octave key. Because it is made from brass it is often included in the brass section alongside true brass instruments like the trumpet or trombone. However, it is not a true brass instrument but a member of the woodwind family of instruments because it has a reed. It was developed from the clarinet and shares many similarities to the clarinet. The player blows into a reed fitted into the mouthpiece of the instrument. Adolf Sax creates the instrument, but at first, it was heavily disliked because he boasted about it. Conductors would not add it to their orchestras because of the horrible reputations it had because of Adolf Sax. It started to gain popularity and lose that bad review, in the early 20th century.

paragraphs: The mouth piece is also a way to tune the saxophone. If you are sharp you can pull the mouthpiece out. If you are flat you can push the mouthpiece in. Another way to tune the saxophone is with your mouth. If you are sharp you 'drop your jaw', or loosen up. If you are flat you tighten your embouchure, (mouth).

paragraphs: There are several different kinds of saxophone. In order from low to high pitch they are: tubax, contrabass, bass, baritone, tenor, alto, soprano, sopranino, and soprillo. However, only the baritone, tenor, alto, and soprano are commonly used.

paragraphs: It was invented in 1840 by Adolphe Sax and is used in classical, jazz, and occasionally in rock, pop, and other styles. The big bands of the 1940s and 1950s always used it too. Famous saxophone players were Marcel Mule (classical music), John Coltrane (jazz music), and Charlie Parker (jazz music).


title: Bryophyte

paragraphs: Bryophytes are simple plants. They are the simplest plants that grow on land. There are three forms of bryophyte. These are mosses, liverworts and hornworts.

paragraphs: Bryophyta is the formal term for this division of plants who do not have tissues to move water. In some modern classifications the word bryophyta only includes mosses. However, the term is still useful because mosses, liverworts, and hornworts share important traits.

paragraphs: Scientists think that liverworts evolved from green algae. Then other plants, including moss and hornworts, evolved from liverworts.

paragraphs: A person who studies bryophytes is called a bryologist. The study of bryophytes is named bryology.

paragraphs: Like all land plants (embryophytes), bryophytes have life cycles with alternation of generations. A bryophyte has two forms that have different numbers of chromosomes. The haploid form has unpaired chromosomes. It is called a gametophyte. People often write "1n" for haploid. The other form is diploid and has paired chromosomes. It is called a sporophyte. People often write "2n" for diploid.

paragraphs: A bryophyte begins when its parent plant makes haploid spores that land on the ground. Each spore grows into a leafy gametophyte. This gametophyte is either male or female. Male gametophytes make haploid sperm. Female gametophytes make haploid eggs. Water moves the sperm to the egg. An embryo is made when they join. This embryo is diploid. It grows a tall stalk from the gametophyte. This stalk is often brown. A structure called the sporangium is at the top of the stalk. The sporangium is diploid too. It makes spores that are haploid in a process called meiosis. When the spores land on the ground, the cycle begins again.

paragraphs: Bryophytes are "gametophyte dominant." This phrase means when you look at a bryophyte, you are more likely to see the gametophyte. The sporophyte is less common. Sporophytes are always attached to the gametophyte. They must get food from the gametophyte. Bryophyte sporophytes do not have branches. They make only one sporangium.


title: Kent

paragraphs: Kent is a county in England. It is just to the south-east of London and is on the coast. The sea to the East of Kent is the North Sea. The sea south of Kent is called the English Channel by the British. France is opposite Kent on the other side of The Channel. At the most narrow point, between Dover, Calais and Cape Gris-Nez, The Channel is only 21 miles (34 km) wide. Dover is one of the main ports in Kent. From here many ferries sail to and from France.

paragraphs: Other main ports in Kent include Sheerness and Ramsgate. The Channel Tunnel goes from Folkestone in Kent to France. It was built in the late 1980s and early 1990s.

paragraphs: Kent is a very ancient county. In the 6th and 7th centuries it was ruled by its own kings, It is often called 'the garden of England' because its countryside is very green and because it produces much fruit. A lot of fruit such as strawberries are grown in Kent, and the county is famous for growing hops which are used to make beer. Maidstone is called the county town because the local government for Kent is based there.

paragraphs: Another important town is the city of Canterbury. The Archbishop of Canterbury is the head of the Church of England. Hundreds of years ago many Christian people would travel to the Cathedral at Canterbury from their homes in other parts of Britain. This was called making a pilgrimage.


title: Gavrilo Princip

paragraphs: Gavrilo Princip, 25 July 1894 – 28 April 1918, was the Serb nationalist who shot Archduke Franz Ferdinand and the wife of the Archduke, Archduchess Sophie Chotek.

paragraphs: Princip was born in Obljaj a poor area of Bosnia. As a young man he joined a small group who wanted the Slavs in the south of Austria-Hungary to join with Serbia in a new country. They called themselves "Young Bosnia". A group of powerful people in Serbia decided to help them. Those powerful people were called the Black Hand. They gave 'Young Bosnia' guns and small bombs.

paragraphs: When they heard that Franz Ferdinand was coming to Sarajevo, six of them took the bombs and guns and waited for Ferdinand to drive past. They were going to kill Ferdinand when he drove past. Every one of them failed. After they all failed, Princip went to a cafe to buy a sandwich.

paragraphs: When Princip came out of the cafe, he saw Ferdinand in his car. The driver of the car had driven his car the wrong way and he stalled the car while trying to turn. Princip walked up and shot Ferdinand. He wanted to shoot the general who was also sitting in the car, but Ferdinand's wife Sophie threw her arms around Ferdinand. She was in the way, and Princip shot her instead of the general.

paragraphs: At his trial, Princip said he did it because he loved his people. The Austrians thought it was a very bad crime, but they could not kill him because he was only 19 years old. The law in Austria-Hungary said only people older than 20 could be killed, even when the crime was as bad as killing royalty like Ferdinand. They said Princip must stay in prison for 20 years. During his time in the prison, one of his arms was amputated. He died in prison of tuberculosis and blood loss in 1918.

paragraphs: Because this crime happened, Austria-Hungary gave Serbia a list of things that Serbia had to do, later called the "July Ultimatum", to stop things like this from happening any more. Serbia could not do all the things on the list fast enough, because the Austrians really wanted war with Serbia. Their German allies also wanted a big war. This led to many of the European countries to start fighting.


title: Formula

paragraphs: In mathematics and science, a formula is a rule or statement written in algebraic symbols. The plural of formula can be written in two ways: formulae or formulas - the choice is based on personal preference.

paragraphs: Formulas use letters instead of words. A simple example of a formula is y = x. If x=1, the formula y=x would make the statement that x is the same thing as y, therefore, y=1.

paragraphs: In mathematics, a formula can also be an identity which equates two mathematical expressions together. Some key formulas under this category include the Pythagorean theorem, binomial theorem, Euler's formula and De Moivre's formula. The expression ""V"="lwh"", which relates the volume "V" to the length "l", width "w" and height "h" of a rectangular box, is another example of a formula in geometry.

paragraphs: In science, one of the most well known formulas is the formula for energy, "e" = "mc", created by Albert Einstein. Here, "e" represents energy, "m" represents mass and "c" is the speed of light. Thus, energy = mass × speed of light .

paragraphs: The "formula" e = mc is also an equation. Every equation is a formula, but not every formula is an equation. For instance, the formula x≡y (x "is defined as" y) is not an equation, because no "=" sign is used.


title: Independence and Democracy

paragraphs: Independence and Democracy is a group in the European Parliament. It used to be called the Group of Europe of Democracies and Diversities. It has about 37 members in it. The members of this group either want their country to leave the European Union, or want to change it.


title: Musician

paragraphs: A musician is a person who plays a musical instrument like a guitar or a piano or a person that sings.

paragraphs: A musician is also someone who writes music, even if they write it for other people to play. People who write music are called composers. Usually that part is left out if they also play or sing the music they write, but they are still composers because they wrote the music.

paragraphs: Musicians can also make a group together to play songs. If the group has many people playing instruments together, like Beethoven's music, it is called an orchestra. If it is just many people singing, like in a church, it is called a choir. If it is only a few people together it is usually just called a band. Sometimes a band has the same name as the singer.


title: Carrot

paragraphs: Carrots are a type of plant. Many different types exist. The Latin name of the plant is usually given as "Daucus carota". The plant has an edible, orange root, and usually white flowers. Wild carrots grow naturally in Eurasia. Domesticated carrots are grown for food in many parts of the world.

paragraphs: Carrots are grown in the ground, and carrots roots are a common edible vegetable. After cleaning, the roots may be eaten raw or cooked. They are served as part of many dishes. In Portugal, carrot jam is a speciality.

paragraphs: Carrots Benefits-Carrot is a root vegetable, easily available, loaded with a lot of nutrients, crunchy, tasty highly beneficial super food for us to be consumed in winters.

paragraphs: Let’s know something about the constitution that makes Carrots Benefits

paragraphs: ◆Carrot is made up of about 90% of water

paragraphs: ◆Lots of fiber, pectin it is a soluble fiber and is helpful to lower glucose by

paragraphs: ●slowing down the digestion of starch in sugar present in our food

paragraphs: ●It is also able to feed the friendly bacteria in our intestine which may result in improved health and reduced risk of illness.

paragraphs: ●Also impairs the absorption of cholesterol in the digestive track lowering blood cholesterol levels

paragraphs: ●It is also good in constipation as being fiber encourages healthy bowel movements.

paragraphs: ●Along with beta-carotene carrots also have carotenoids another antioxidant helpful to enhance  immunity functions and decreased risk of cardiovascular diseases, degenerative diseases and different types of cancers