ejaasaari/simplewiki-2025-04-01 huggingface dataset:
An electrical cell is a device used to generate electricity, or to make chemical reactions by applying electricity. A battery is one or more cells, connected. This cell is also known as electrochemical cell. Cells producing electricity. The simple electrical cells were first developed in 1800s. They are also called "galvanic cells", because an Italian scientist named Luigi Galvani invented these cells. Special chemical reactions which occur inside the electrical cell, result in oxidation and reduction of the substances inside the cell. This produces electrical energy. Normal batteries work like this. Some electrical cells produce electricity without using chemical energy. For example, solar cells produce electricity when they are exposed to sun light. A plate of zinc and a plate of copper immersed in a dilute solution which contains acid or salt is an example of the chemical reaction based cell. The solution acts as an electrolyte (electric conductor). When the two plates are connected to a current meter with a wire, electric current will pass; this is because oxidation and reduction processes take place in this chemical reaction turning the zinc plate to a negative electrode and the copper plate to a positive electrode, and so the electrons flow from zinc to copper. Cells using electricity. Some chemical reactions need high energy to happen. An example is the breakdown of water into hydrogen and oxygen. An electrical cell (or an "electrolytic cell") is used for these reactions. It is a container which has to have a chemical reaction involving electrodes. The chemical substances are exposed to electrical power, and the electrolysis reaction happens inside the electrical cell. Two pieces of metal are placed in water that has a little electrolyte such as hydrochloric acid, sulfuric acid, sodium bicarbonate, or sodium hydroxide added to it. An electric current is applied and gas comes out of each electrode. Some greenish-brown color may be seen too if iron was used.  There may also be a chemical reaction which will result in the explosion of the iron and has a strong blast radius (safety goggles recommended).
Dry cells are a type of chemical cells. Dry cells are commonly used today in the form of batteries. Dry cells are used in many electrical appliances. Most dry cells are not truly dry; they still contain a liquid electrolyte, but it is immobilized in a paste or gel. Several truly dry, or solid-state, batteries have been developed, but none are commercially available yet. Types of dry cells. Primary cells are not rechargeable. They have to be thrown away after their chemicals are used. Secondary cells are rechargeable. They can be used again.
The Vietnam War (also known as Second Indochina War, Vietnamese-American War or American War in Vietnam) lasted from 1 November 1955 to 30 April 1975. It was fought between North Vietnam and South Vietnam. North Vietnam was supported by the Soviet Union, China, and North Korea, and South Vietnam was set up by the United States and supported by South Korea, Thailand, Australia, New Zealand, and the Philippines. People from other countries also went to fight but not in their own national armies. The conflict between communist and capitalist countries was part of the Cold War. The Viet Cong, also known as the National Liberation Front or NLF, was a South Vietnamese communist force that was helped by North Vietnam. It fought a guerrilla war against non-communist South Vietnamese forces. The People's Army of Vietnam (also known as the North Vietnamese Army) engaged in a more conventional war by at times putting large forces to battle. The Vietnam War was very controversial, especially in the United States. It was the first war to feature live television coverage and the first major armed conflict that the United States lost. The war became so unpopular in the United States that President Richard Nixon eventually agreed to send American soldiers home in 1973. Background and causes. France began to colonize Vietnam between 1859 and 1862, when it took control of Saigon. By 1864, it had controlled all of Cochinchina, in the south of Vietnam. France took control of Annam, the large central part of Vietnam, in 1874. After France defeated China during the Sino-French War (1884–1885), it took over Tonkin, the north of Vietnam. French Indochina was formed in October 1887 from these three areas of Vietnam (Cochinchina, Annam and Tonkin), as well as Cambodia. Laos was added after a war against Thailand, the Franco-Siamese War, in 1893. During World War II, after Nazi Germany had defeated France in 1940, French Indochina was controlled by the Vichy French government, a puppet government recognized by Germany. In March 1945, the Japanese
The Sahel is a narrow belt of land in North Africa. It is a strip of land about 5500 kilometers long and 450 kilometres wide. It lies at the southern edge of the Sahara Desert  The Sahel has a tropical semi-arid climate. It is between the dry desert land to the north and the forest areas to the south. The temperature is high throughout the year. There is little rainfall in the Sahel (between 100 and 150 mm and 600mm). It comes during summer months and may be unreliable. It may be very dry in some years, especially if a large area of low pressure, which brings rain, is not carried North over the Sahel by strong winds. Sahel is the Arabic word for 'edge' or 'shore'. The Sahel is facing a big problem, desertification. The distribution of rainfall in the Sahel region is uneven. The rainfall in the region has been below average since 1970. The Sahel is becoming drier on the whole. The problem of drought affects most of the countries in the Sahel. As a result, crops and animals die. There is no vegetation to protect the soil, which is then removed by flash floods and strong wind. This leads to soil erosion. Finally, the desert spreads towards the surrounding areas. With better medical services, the birth rate increases and the death rate decreases in the Sahel. As a result, the population in the Sahel is growing. To meet the ever-increasing demand for firewood, a lot of trees have been cut down. More land has become barren. This is called deforestation. Furthermore, people farm intensively in order to grow more crops, the soil becomes infertile with a lack of nutrients. If this process continues for a long time, no crops can be grown. This is called overcultivation. People keep animals for food due to the lack of good soil, the animals will have to eat grass and etc. But as the animals eat the grass, they also dug up the soil. As people keep too many animals, the demand for grass is too great. Soil erosion is caused while the animals keep digging the soil up as they eat, and the wind and rain blow away the soil. This process is called overgrazing.
A chemical change (chemical reaction) is a change of materials into other materials with different properties. Chemical changes occur when a substance combines with another to form a new substance, or, chemical decomposition into two or more different substances. These processes are called chemical reactions. Burning of wood is a chemical change as new substances which cannot be changed back (e.g. carbon dioxide) are formed. For example, if wood is burned in a fireplace, there is not wood anymore but ash. Other examples include burning of a candle, rusting of iron, baking a cake, etc. Special details that describe how a chemical change takes place are called chemical properties.  Compare: physical change. The opposite of a chemical change is a physical change. Physical changes are a change in which no new substances are formed, and the substance which is changed is the same. For instance, if a stick of wood is broken, there is still a stick of wood; it is just broken.  More examples include changes of shape, changes of states, passing electricity through a copper wire, breaking of wood, shattering of glass, pouring of water, etc. Special details which do not change in a substance without new substances being formed are called physical properties.
A physical change is a type of change in which the form of matter is altered but one substance is not transformed into another. The size or shape of matter may be changed, but no chemical reaction occurs. All physical changes are reversible and their mass does not change. Some examples are changes of shape, changes of states, and passing electricity through a copper wire. Physical changes could be: melting, freezing, boiling/evaporating, condensing, deposition and sublimation. Many physical changes also involve the rearrangement of atoms most noticeably in the formation of crystals. Many chemical changes are irreversible, and many physical changes are reversible, but reversibility is not a certain criterion for classification. Although chemical changes may be recognized by an indication such as odor, color change, or production of a gas, every one of these indicators can result from physical change.
Ronald Wilson Reagan ( ; February 6, 1911June 5, 2004) was the 40th president of the United States, serving from 1981 to 1989. Before becoming president, he was the 33rd governor of California from 1967 to 1975. He was also the 9th and 13th president of the Screen Actors Guild from 1947 to 1952 and again from 1959 until 1960. Reagan got a degree from Eureka College in 1932 and became a sports broadcaster in Iowa. In 1937, Reagan moved to California, where he became a movie actor. From 1947 to 1952, Reagan was the president of the Screen Actors Guild. In the 1950s, he worked in television and spoke for General Electric. From 1959 to 1960, he again was the Screen Actors Guild's president. In 1964, "A Time for Choosing" gave Reagan attention as a new conservative figure. He was elected governor of California in 1966. During his time as governor, he raised taxes, fixed the state's budget, and ended student protests in Berkeley. After running against and losing to president Gerald Ford in the 1976 Republican presidential primaries, Reagan won the Republican nomination and then a landslide victory over Democratic president Jimmy Carter in the 1980 United States presidential election. In his first term, Reagan created "Reaganomics", which included economic deregulation and cuts in both taxes and government spending during a time of stagflation. He grew an arms race and had a more intense response with the Soviet Union. He also survived an assassination attempt, had a problems with public sector labor unions, made the war on drugs bigger, and ordered the invasion of Grenada in 1983. In the 1984 presidential election, Reagan was re-elected over former vice president Walter Mondale in another landslide victory. Foreign policy took over Reagan's second term, including the 1986 bombing of Libya, the Iran–Iraq War, the secret sale of arms to Iran to fund the Contras, and a more calm response in talks with Soviet leader Mikhail Gorbachev
The United Nations (UN) is an organization between countries established on 24 October 1945 to promote international cooperation. It was founded to replace the League of Nations following World War II and to prevent another conflict. When it was founded, the UN had 51 members. Now there are 193. Most nations are members of the UN and send diplomats to the headquarters to hold meetings and make decisions about global issues. The goals of the United Nations are: History. After World War I, the nations of the world formed the League of Nations. The organization was a place where nations could talk through their differences calmly. However, some countries like Germany, Italy, and Japan ignored the League. They tried to solve their problems through war. Members of the League of Nations did not want to go to war to protect other members and so it failed. World War II soon started. The Allies of World War II often called themselves "the United Nations" since they were united against the Axis Powers. After the war, the winners formed a new organization for world peace. On 25 April 1945 in San Francisco, they decided on the name '"United Nations". In June, they signed the United Nations Charter and decided how the organization would work. The UN was created on 24 October 1945, and its first meeting was held in January 1946. Since 1947 24 October has been called “United Nations Day”. The only country whose flag is modeled after the United Nations is Somalia. Headquarters. The United Nations is based in New York City, United States, except for the International Court of Justice, which is in The Hague, Netherlands. The leader of the United Nations is called United Nations Secretary-General. Activity. The UN's main buildings are in New York City. The UN also has offices in Geneva, Switzerland, Kenya, and Austria. The UN tries to be peaceful but it has been involved in armed conflicts. In the 1950s during the Soviet boycott of United Nations Security Council, the UN supported South Korea in a war against North Korea. In the 1990s, the UN helped to force Iraqi soldiers out of Kuwait. At other times, the UN has built peacekeeping forces.
This is a list of historians. The names are grouped by order of the historical period in which they were writing, which is not necessarily the same as the period in which they specialised. Chroniclers and annalists, though they are not historians in the true sense, are also listed here for convenience.
Marco Polo was born in 1254 and died on January 8, 1324. He was an Italian trader and explorer. He was one of the first Europeans to explore Central Asia and East Asia. Many other explorers, including Christopher Columbus, looked up to him. He spoke four languages. Marco Polo was known for the book, "Travels of Marco Polo," where he talked about Asia. Early life. Marco Polo was born in Venice, one of the most successful trading cities. Polo's mother died when he was very young and he was raised by his aunt and uncle. His father and uncle returned from their Silk Road travels when Marco was about 15 years old. Two years later, the three of them started their journey to Cathay (China). His family were well-known merchants, not explorers. He learned about writing, reading, and arithmetic, and how to do business. Travels. Polo went on a 24-year trip to China with his father and uncle during the Mongol Dynasty. He left Venice at the age of 17 on a boat that went through the Mediterranean Sea, to Acre, and later to Tabriz and Kerman. Then he travelled across Asia getting as far as Beijing. On the way there he went over mountains and through deserts, across scorching hot lands and places where the cold was unbearable. Arriving in Cathay at age 21, he served in Kublai Khan's court for 17 years. He left the Far East and returned to Venice by sea. There was sickness on board and 600 passengers and crew died. Nevertheless, Marco Polo survived the journey. Polo returned to Venice with treasures like ivory, jade, jewels, porcelain and silk. Some scholars believe that while Marco Polo did go to China, they doubt that he went to all of the other places described in his book. "Travels of Marco Polo". Soon after Polo returned from his journeys he fought in a war against Genoa, got captured and put in prison. When he was in prison, he became friendly with a fellow prisoner, Rusticello, who was a writer of romances and novels. He told the writer about all his adventures, which
Herpes zoster (also known as shingles or zona) is a disease in humans. The same virus that causes chickenpox also causes shingles. The symptoms are pain and a rash with blisters. The shingles vaccine reduces the risk of shingles. Antivirus medicine can reduce the seriousness and duration of shingles if started within 3 days of the rash. General information. Shingles is a viral disease produced by the (VZV), the same virus that causes chicken pox. Its symptoms include pain and a blistering rash that occurs along the nerves that contain dormant virus. You can not catch shingles. However, you can catch chicken pox through direct contact with someone who has shingles, by touching the area of the rash. Most people who get shingles are old. It sometimes infects younger people, or people with a weakened immune system. Stress may trigger shingles. The disease starts with tingling, itchiness, or pain on an infected person's skin. After a few days, the disease causes a blistering rash. This rash may be on the trunk or face. The rash grows into small blisters filled with fluid. These blisters dry out and crust over for several days. The rash causes anything from mild itching to extreme pain. The rash stays in one region of the body. The shingles virus is contagious from person to person only by direct contact. For this reason, persons with shingles are advised to limit contact with those who are not immune to chicken pox, those with increased risk are young children and pregnant women. Contracting chickenpox when one is pregnant can be dangerous to the unborn child. If people have had chickenpox, they cannot get chickenpox from someone else again. However, it is thought that contact with a shingles patient may trigger a person's own dormant chickenpox virus to become shingles. Treatment. Doctors recommend antiviral drugs, steroids, antidepressants, anticonvulsants, and topical agents to treat shingles. The antiviral drugs acyclovir, valacyclovir, and famcyclovir can reduce the severity of shingles. Prognosis. Shingles can
A Brief History of Time (1988) is a book written by the scientist and mathematician Stephen Hawking. The subject of the book is cosmology, the story of the universe. There are two other versions of this book: The "Illustrated A Brief History of Time" and "A Briefer History of Time". The Illustrated A Brief History of Time has pictures to help explain its ideas. It was also updated because new information was found. A Briefer History of Time is shorter than the first version and was also updated. This book is very popular and well-known. This book was on the "London Sunday Times" bestseller list for over 4 years. Summary. In this book, Hawking talks about many theories in physics. Some of the things that he talks about are the history of physics, gravity, how light moves in the universe, space-time, elementary particles (very small objects that make up things in the universe), black holes, the Big Bang (the theory that the universe started from one point), and time travel (the idea that travel can be done to the past and to the future.) In the first part of the book, Hawking talks about the history of physics. He talks about the ideas of philosophers such as Aristotle and Ptolemy. Aristotle, unlike many other people of his time, thought that the Earth was round. He also thought that the sun and stars went around the Earth. Ptolemy also thought about how the sun and stars were located in the universe. He made a planetary model that described Aristotle's thinking. Today, it is known that the opposite is true; the earth goes around the sun. The Aristotle/Ptolemy ideas about the position of the stars and sun was disproved in 1609. The person who first thought of the idea about the Earth going around the sun was Nicholas Copernicus. Galileo Galilei and Johannes Kepler, two other scientists, helped to prove that Copernicus's idea was right. They looked at how the moons of some planets moved in the sky, and they used this to prove Copernicus right. Isaac Newton also wrote a book about gravity, which helped to prove Copern
Alexander Graham Bell (March 3, 1847 – August 2, 1922) was a Scottish-born British-Canadian-American teacher, scientist, and inventor. He was the founder of the Bell Telephone Company. In 1876, Bell was the first inventor to patent the telephone, and he helped start the Bell Telephone Company with others in July 1877. In 1879, this company joined with the New England Telephone Company to form the National Bell Telephone Company. In 1880, they formed the American Bell Telephone Company. In 1885, they formed the American Telephone and Telegraph Company (AT&amp;T), which is still a large company today. Along with Thomas Edison, Bell formed the Oriental Telephone Company on January 25, 1881. Early life. Alexander Graham Bell was born in Edinburgh, Scotland. His family was known for teaching people how to speak English clearly (elocution). Both his grandfather, Alexander Bell, and his father, Alexander Melville Bell, taught elocution. His father wrote often about this and is most known for his invention and writings of Visible Speech. In his writings he explained ways of teaching people who were deaf and Mute. It also showed how these people could learn to speak words by watching their lips and reading what other people were saying. Education. Alexander Graham Bell went to the Royal High School of Edinburgh. He graduated at the age of fifteen. At the age of sixteen, he got a job as a student and teacher of elocution and music in Weston House Academy, at Elgin in Morayshire. He spent the next year at the University of Edinburgh. While still in Scotland, he became more interested in the science of sound (acoustics). He hoped to help his deaf mother. From 1866 to 1867, he was a teacher at Somersetshire College in Bath, Somerset. Career. In 1870 when he was 23 years old, he moved with his family to Canada where they settled at Brantford, Ontario. Bell began to study communication machines. He made a piano that could be heard far away by using electricity. In 1871 he went with his father to Montreal, Quebec
Heinrich Rudolf Hertz (22 February 1857 – 1 January 1894) was a German physicist. In 1888 he discovered the radio waves previously predicted by Maxwell's equations. He also proved that light is a kind of electromagnetic waves. The unit for frequency is named after him. Hertz was born in Hamburg in 1857. He studied engineering in Frankfurt and later at the University of Munich. He completed his PhD at the University of Berlin. He taught and continued research at the University of Bonn and University of Kiel. He died from blood poisoning in 1894.
1815 (MDCCCXV) was a common year starting on Sunday in the Gregorian calendar and a common year starting on Friday in the Julian calendar.
Cytokines are a group of signalling molecules made by cells. They help to control the immune system and fight disease. They are similar to hormones and, as we learn more about each, distinctions between the two are fading. Cytokines carry signals locally between cells, and these signals have an effect on other cells. They are made of proteins, peptides, or glycoproteins. The cytokines are a large family of polypeptide regulators that are produced throughout the body by many groups of cells. Some well-known cytokines include interferon, prostaglandin and interleukins. Cytokines can be detected using the ELISA and ELISPOT techniques. Cytokines work by signal transduction. Each cytokine has a matching cell-surface receptor. Then cascades of signals inside the cell changes cell functions. This may include the regulation of several genes, the production of other cytokines, or an increase in surface receptors for other molecules.