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Interspecies. Most communication happens between members within a species as intraspecies communication. This is because the purpose of communication is usually some form of cooperation. Cooperation happens mostly within a species while different species are often in conflict with each other by competing over resources. However, there are also some forms of interspecies communication. This occurs especially for symbiotic relations and significantly less for parasitic or predator-prey relations. Interspecies communication plays a key role for plants that depend on external agents for reproduction. For example, flowers need insects for pollination and provide resources like nectar and other rewards in return. They use communication to signal their benefits and attract visitors by using distinctive colors and symmetrical shapes to stand out from their surroundings. This form of advertisement is necessary since flowers compete with each other for visitors. Many fruit-bearing plants rely on plant-to-animal communication to disperse their seeds and move them to a favorable location. This happens by providing nutritious fruits to animals. The seeds are eaten together with the fruit and are later excreted at a different location. Communication makes animals aware of where the fruits are and whether they are ripe. For many fruits, this happens through their color: they have an inconspicuous green color until they ripen and take on a new color that stands in visual contrast to the environment. Another example of interspecies communication is found in the ant-plant relation. It concerns, for instance, the selection of seeds by ants for their ant gardens and the pruning of exogenous vegetation as well as plant protection by ants.
Some animal species also engage in interspecies communication, like apes, whales, dolphins, elephants, and dogs. For example, different species of monkeys use common signals to cooperate when threatened by a common predator. Humans engage in interspecies communication when interacting with pets and working animals. For instance, acoustic signals play a central role in communication with dogs. Dogs can learn to react to various commands, like "sit" and "come". They can even be trained to respond to short syntactic combinations, like "bring X" or "put X in a box". They also react to the pitch and frequency of the human voice to detect emotions, dominance, and uncertainty. Dogs use a range of behavioral patterns to convey their emotions to humans, for example, in regard to aggressiveness, fearfulness, and playfulness. Computer. Computer communication concerns the exchange of data between computers and similar devices. For this to be possible, the devices have to be connected through a transmission system that forms a network between them. A transmitter is needed to send messages and a receiver is needed to receive them. A personal computer may use a modem as a transmitter to send information to a server through the public telephone network as the transmission system. The server may use a modem as its receiver. To transmit the data, it has to be converted into an electric signal. Communication channels used for transmission are either analog or digital and are characterized by features like bandwidth and latency.
There are many forms of computer networks. The most commonly discussed ones are LANs and WANs. "LAN" stands for "local area network", which is a computer network within a limited area, usually with a distance of less than one kilometer. This is the case when connecting two computers within a home or an office building. LANs can be set up using a wired connection, like Ethernet, or a wireless connection, like Wi-Fi. "WANs", on the other hand, are "wide area networks" that span large geographical regions, like the internet. Their networks are more complex and may use several intermediate connection nodes to transfer information between endpoints. Further types of computer networks include PANs (personal area networks), CANs (campus area networks), and MANs (metropolitan area networks).
Human-computer communication is a closely related field that concerns topics like how humans interact with computers and how data in the form of inputs and outputs is exchanged. This happens through a user interface, which includes the hardware used to interact with the computer, like a mouse, a keyboard, and a monitor, as well as the software used in the process. On the software side, most early user interfaces were command-line interfaces in which the user must type a command to interact with the computer. Most modern user interfaces are graphical user interfaces, like Microsoft Windows and macOS, which are usually much easier to use for non-experts. They involve graphical elements through which the user can interact with the computer, commonly using a design concept known as skeumorphism to make a new concept feel familiar and speed up understanding by mimicking the real-world equivalent of the interface object. Examples include the typical computer folder icon and recycle bin used for discarding files. One aim when designing user interfaces is to simplify the interaction with computers. This helps make them more user-friendly and accessible to a wider audience while also increasing productivity.
Communication studies. Communication studies, also referred to as "communication science", is the academic discipline studying communication. It is closely related to semiotics, with one difference being that communication studies focuses more on technical questions of how messages are sent, received, and processed. Semiotics, on the other hand, tackles more abstract questions in relation to meaning and how signs acquire it. Communication studies covers a wide area overlapping with many other disciplines, such as biology, anthropology, psychology, sociology, linguistics, media studies, and journalism. Many contributions in the field of communication studies focus on developing models and theories of communication. Models of communication aim to give a simplified overview of the main components involved in communication. Theories of communication try to provide conceptual frameworks to accurately present communication in all its complexity. Some theories focus on communication as a practical art of discourse while others explore the roles of signs, experience, information processing, and the goal of building a social order through coordinated interaction. Communication studies is also interested in the functions and effects of communication. It covers issues like how communication satisfies physiological and psychological needs, helps build relationships, and assists in gathering information about the environment, other individuals, and oneself. A further topic concerns the question of how communication systems change over time and how these changes correlate with other societal changes. A related topic focuses on psychological principles underlying those changes and the effects they have on how people exchange ideas.
Communication was studied as early as Ancient Greece. Early influential theories were created by Plato and Aristotle, who stressed public speaking and the understanding of rhetoric. According to Aristotle, for example, the goal of communication is to persuade the audience. The field of communication studies only became a separate research discipline in the 20th century, especially starting in the 1940s. The development of new communication technologies, such as telephone, radio, newspapers, television, and the internet, has had a big impact on communication and communication studies. Today, communication studies is a wide discipline. Some works in it try to provide a general characterization of communication in the widest sense. Others attempt to give a precise analysis of one specific form of communication. Communication studies includes many subfields. Some focus on wide topics like interpersonal communication, intrapersonal communication, verbal communication, and non-verbal communication. Others investigate communication within a specific area. Organizational communication concerns communication between members of organizations such as corporations, nonprofits, or small businesses. Central in this regard is the coordination of the behavior of the different members as well as the interaction with customers and the general public. Closely related terms are business communication, corporate communication, and professional communication. The main element of marketing communication is advertising but it also encompasses other communication activities aimed at advancing the organization's objective to its audiences, like public relations. Political communication covers topics like electoral campaigns to influence voters and legislative communication, like letters to a congress or committee documents. Specific emphasis is often given to propaganda and the role of mass media.
Intercultural communication is relevant to both organizational and political communication since they often involve attempts to exchange messages between communicators from different cultural backgrounds. The cultural background affects how messages are formulated and interpreted and can be the cause of misunderstandings. It is also relevant for development communication, which is about the use of communication for assisting in development, like aid given by first-world countries to third-world countries. Health communication concerns communication in the field of healthcare and health promotion efforts. One of its topics is how healthcare providers, like doctors and nurses, should communicate with their patients. History. Communication history studies how communicative processes evolved and interacted with society, culture, and technology. Human communication has a long history and the way people communicate has changed considerably over time. Many of these changes were triggered by the development of new communication technologies and had various effects on how people exchanged ideas. New communication technologies usually require new skills that people need to learn to use them effectively.
In the academic literature, the history of communication is usually divided into ages based on the dominant form of communication in that age. The number of ages and the precise periodization are disputed. They usually include ages for speaking, writing, and print as well as electronic mass communication and the internet. According to communication theorist Marshall Poe, the dominant media for each age can be characterized in relation to several factors. They include the amount of information a medium can store, how long it persists, how much time it takes to transmit it, and how costly it is to use the medium. Poe argues that subsequent ages usually involve some form of improvement of one or more of the factors.
Most early written communication happened through pictograms. Pictograms are graphical symbols that convey meaning by visually resembling real-world objects. The use of basic pictographic symbols to represent things like farming produce was common in ancient cultures and began around 9000 BCE. The first complex writing system including pictograms was developed around 3500 BCE by the Sumerians and is called cuneiform. Pictograms are still in use today, like no-smoking signs and the symbols of male and female figures on bathroom doors. A significant disadvantage of pictographic writing systems is that they need a large amount of symbols to refer to all the objects one wants to talk about. This problem was solved by the development of other writing systems. For example, the symbols of alphabetic writing systems do not stand for regular objects. Instead, they relate to the sounds used in spoken language. Other types of early writing systems include logographic and ideographic writing systems. A drawback of many early forms of writing, like the clay tablets used for cuneiform, was that they were not very portable. This made it difficult to transport the texts from one location to another to share information. This changed with the invention of papyrus by the Egyptians around 2500 BCE and was further improved later by the development of parchment and paper.
Until the 1400s, almost all written communication was hand-written, which limited the spread of written media within society since copying texts by hand was costly. The introduction and popularization of mass printing in the middle of the 15th century by Johann Gutenberg resulted in rapid changes. Mass printing quickly increased the circulation of written media and also led to the dissemination of new forms of written documents, like newspapers and pamphlets. One side effect was that the augmented availability of written documents significantly improved the general literacy of the population. This development served as the foundation for revolutions in various fields, including science, politics, and religion.
Classics Classics, also classical studies or Ancient Greek and Roman studies, is the study of classical antiquity. In the Western world, "classics" traditionally refers to the study of Ancient Greek and Roman literature and their original languages, Ancient Greek and Latin. Classics may also include as secondary subjects Greco-Roman philosophy, history, archaeology, anthropology, art, mythology, and society. In Western civilization, the study of the Ancient Greek and Roman classics was considered the foundation of the humanities, and they traditionally have been the cornerstone of an elite higher education. Etymology. The word "classics" is derived from the Latin adjective "classicus", meaning "belonging to the highest class of citizens." The word was originally used to describe the members of the Patricians, the highest class in ancient Rome. By the 2nd century AD the word was used in literary criticism to describe writers of the highest quality. For example, Aulus Gellius, in his "Attic Nights", contrasts "classicus" and "proletarius" writers. By the 6th century AD, the word had acquired a second meaning, referring to pupils at a school. Thus, the two modern meanings of the word, referring both to literature considered to be of the highest quality and the standard texts used as part of a curriculum, were both derived from Roman use.
History. Middle Ages. In the Middle Ages, classics and education were tightly intertwined; according to Jan Ziolkowski, there is no era in history in which the link was tighter. Medieval education taught students to imitate earlier classical models, and Latin continued to be the language of scholarship and culture, despite the increasing difference between literary Latin and the vernacular languages of Europe during the period. While Latin was hugely influential, according to thirteenth-century English philosopher Roger Bacon, "there are not four men in Latin Christendom who are acquainted with the Greek, Hebrew, and Arabic grammars." Greek was rarely studied in the West, and Greek literature was known almost solely in Latin translation. The works of even major Greek authors such as Hesiod, whose names continued to be known by educated Europeans, along with most of Plato, were unavailable in Christian Europe. Some were rediscovered through Arabic translations; a School of Translators was set up in the border city of Toledo, Spain, to translate from Arabic into Latin.
Along with the unavailability of Greek authors, there were other differences between the classical canon known today and the works valued in the Middle Ages. Catullus, for instance, was almost entirely unknown in the medieval period. The popularity of different authors also waxed and waned throughout the period: Lucretius, popular during the Carolingian Renaissance, was barely read in the twelfth century, while for Quintilian the reverse is true. Renaissance. The Renaissance led to the increasing study of both ancient literature and ancient history, as well as a revival of classical styles of Latin. From the 14th century, first in Italy and then increasingly across Europe, Renaissance Humanism, an intellectual movement that "advocated the study and imitation of classical antiquity", developed. Humanism saw a reform in education in Europe, introducing a wider range of Latin authors as well as bringing back the study of Greek language and literature to Western Europe. This reintroduction was initiated by Petrarch (1304–1374) and Boccaccio (1313–1375) who commissioned a Calabrian scholar to translate the Homeric poems. This humanist educational reform spread from Italy, in Catholic countries as it was adopted by the Jesuits, and in countries that became Protestant such as England, Germany, and the Low Countries, in order to ensure that future clerics were able to study the New Testament in the original language.
Neoclassicism. The late 17th and 18th centuries are the period in Western European literary history which is most associated with the classical tradition, as writers consciously adapted classical models. Classical models were so highly prized that the plays of William Shakespeare were rewritten along neoclassical lines, and these "improved" versions were performed throughout the 18th century. In the United States, the nation's Founders were strongly influenced by the classics, and they looked in particular to the Roman Republic for their form of government. From the beginning of the 18th century, the study of Greek became increasingly important relative to that of Latin. In this period Johann Winckelmann's claims for the superiority of the Greek visual arts influenced a shift in aesthetic judgements, while in the literary sphere, G. E. Lessing "returned Homer to the centre of artistic achievement". In the United Kingdom, the study of Greek in schools began in the late 18th century. The poet Walter Savage Landor claimed to have been one of the first English schoolboys to write in Greek during his time at Rugby School. In the United States, philhellenism began to emerge in the 1830s, with a turn "from a love of Rome and a focus on classical grammar to a new focus on Greece and the totality of its society, art, and culture." 19th century.
The 19th century saw the influence of the classical world, and the value of a classical education, decline, especially in the United States, where the subject was often criticised for its elitism. By the 19th century, little new literature was still being written in Latin – a practice which had continued as late as the 18th century – and a command of Latin declined in importance. Correspondingly, classical education from the 19th century onwards began to increasingly de-emphasise the importance of the ability to write and speak Latin. In the United Kingdom this process took longer than elsewhere. Composition continued to be the dominant classical skill in England until the 1870s, when new areas within the discipline began to increase in popularity. In the same decade came the first challenges to the requirement of Greek at the universities of Oxford and Cambridge, though it would not be finally abolished for another 50 years. Though the influence of classics as the dominant mode of education in Europe and North America was in decline in the 19th century, the discipline was rapidly evolving in the same period. Classical scholarship was becoming more systematic and scientific, especially with the "new philology" created at the end of the 18th and beginning of the 19th century. Its scope was also broadening: it was during the 19th century that ancient history and classical archaeology began to be seen as part of classics, rather than separate disciplines. 20th century to present.
During the 20th century, the study of classics became less common. In England, for instance, Oxford and Cambridge universities stopped requiring students to have qualifications in Greek in 1920, and in Latin at the end of the 1950s. When the National Curriculum was introduced in England, Wales, and Northern Ireland in 1988, it did not mention the classics. By 2003, only about 10% of state schools in Britain offered any classical subjects to their students at all. In 2016, AQA, the largest exam board for A-Levels and GCSEs in England, Wales and Northern Ireland, announced that it would be scrapping A-Level subjects in Classical Civilisation, Archaeology, and Art History. This left just one out of five exam boards in England which still offered Classical Civilisation as a subject. The decision was immediately denounced by archaeologists and historians, with Natalie Haynes of "The Guardian" stating that the loss of the A-Level would deprive state school students, 93% of all students, the opportunity to study classics while making it once again the exclusive purview of wealthy private-school students.
However, the study of classics has not declined as fast elsewhere in Europe. In 2009, a review of "Meeting the Challenge", a collection of conference papers about the teaching of Latin in Europe, noted that though there is opposition to the teaching of Latin in Italy, it is nonetheless still compulsory in most secondary schools. The same may also be said in the case of France or Greece. Indeed, Ancient Greek is one of the compulsory subjects in Greek secondary education, whereas in France, Latin is one of the optional subjects that can be chosen in a majority of middle schools and high schools. Ancient Greek is also still being taught, but not as much as Latin. Subdisciplines. One of the most notable characteristics of the modern study of classics is the diversity of the field. Although traditionally focused on ancient Greece and Rome, the study now encompasses the entire ancient Mediterranean world, thus expanding the studies to Northern Africa and parts of the Middle East. Philology. Philology is the study of language preserved in written sources; classical philology is thus concerned with understanding any texts from the classical period written in the classical languages of Latin and Greek.
The roots of classical philology lie in the Renaissance, as humanist intellectuals attempted to return to the Latin of the classical period, especially of Cicero, and as scholars attempted to produce more accurate editions of ancient texts. Some of the principles of philology still used today were developed during this period; for instance, the observation that if a manuscript could be shown to be a copy of an earlier extant manuscript, then it provides no further evidence of the original text, was made as early as 1489 by Angelo Poliziano. Other philological tools took longer to be developed: the first statement, for instance, of the principle that a more difficult reading should be preferred over a simpler one, was in 1697 by Jean Le Clerc. The modern discipline of classical philology began in Germany at the turn of the nineteenth century. It was during this period that scientific principles of philology began to be put together into a coherent whole, in order to provide a set of rules by which scholars could determine which manuscripts were most accurate. This "new philology", as it was known, centered around the construction of a genealogy of manuscripts, with which a hypothetical common ancestor, closer to the original text than any existing manuscript, could be reconstructed.
Archaeology. Classical archaeology is the oldest branch of archaeology, with its roots going back to J. J. Winckelmann's work on Herculaneum in the 1760s. It was not until the last decades of the 19th century, however, that classical archaeology became part of the tradition of Western classical scholarship. It was included as part of Cambridge University's Classical Tripos for the first time after the reforms of the 1880s, though it did not become part of Oxford's Greats until much later. The second half of the 19th century saw Schliemann's excavations of Troy and Mycenae; the first excavations at Olympia and Delos; and Arthur Evans' work in Crete, particularly on Knossos. This period also saw the foundation of important archaeological associations (e.g. the Archaeological Institute of America in 1879), including many foreign archaeological institutes in Athens and Rome (the American School of Classical Studies at Athens in 1881, British School at Athens in 1886, American Academy in Rome in 1895, and British School at Rome in 1900).
More recently, classical archaeology has taken little part in the theoretical changes in the rest of the discipline, largely ignoring the popularity of "New Archaeology", which emphasized the development of general laws derived from studying material culture, in the 1960s. New Archaeology is still criticized by traditional minded scholars of classical archaeology despite a wide acceptance of its basic techniques. Art history. Some art historians focus their study on the development of art in the classical world. Indeed, the art and architecture of ancient Rome and Greece is very well regarded and remains at the heart of much of our art today. For example, ancient Greek architecture gave us the classical orders: Doric, Ionic, and Corinthian. The Parthenon is still the architectural symbol of the classical world. Greek sculpture is well known and we know the names of several ancient Greek artists: for example, Phidias. Ancient history. With philology, archaeology, and art history, scholars seek understanding of the history and culture of a civilization, through critical study of the extant literary and physical artefacts, in order to compose and establish a continual historic narrative of the Ancient World and its peoples. The task is difficult due to a dearth of physical evidence: for example, Sparta was a leading Greek city-state, yet little evidence of it survives to study, and what is available comes from Athens, Sparta's principal rival; likewise, the Roman Empire destroyed most evidence (cultural artefacts) of earlier, conquered civilizations, such as that of the Etruscans.
Philosophy. The English word "philosophy" comes from the Greek word φιλοσοφία, meaning "love of wisdom", probably coined by Pythagoras. Along with the word itself, the discipline of philosophy as we know it today has its roots in ancient Greek thought, and according to Martin West "philosophy as we understand it is a Greek creation". Ancient philosophy was traditionally divided into three branches: logic, physics, and ethics. However, not all of the works of ancient philosophers fit neatly into one of these three branches. For instance, Aristotle's "Rhetoric" and "Poetics" have been traditionally classified in the West as "ethics", but in the Arabic world were grouped with logic; in reality, they do not fit neatly into either category. From the last decade of the eighteenth century, scholars of ancient philosophy began to study the discipline historically. Previously, works on ancient philosophy had been unconcerned with chronological sequence and with reconstructing the reasoning of ancient thinkers; with what Wolfgang-Ranier Mann calls "New Philosophy", this changed.
Reception studies. Another discipline within the classics is "reception studies", which developed in the 1960s at the University of Konstanz. Reception studies is concerned with how students of classical texts have understood and interpreted them. As such, reception studies is interested in a two-way interaction between reader and text, taking place within a historical context. Though the idea of an "aesthetics of reception" was first put forward by Hans Robert Jauss in 1967, the principles of reception theory go back much earlier than this. As early as 1920, T. S. Eliot wrote that "the past [is] altered by the present as much as the present is directed by the past"; Charles Martindale describes this as a "cardinal principle" for many versions of modern reception theory. Classical Greece. Ancient Greece was the civilization belonging to the period of Greek history lasting from the Archaic period, beginning in the eighth century BC, to the Roman conquest of Greece after the Battle of Corinth in 146 BC. The Classical period, during the fifth and fourth centuries BC, has traditionally been considered the height of Greek civilisation. The Classical period of Greek history is generally considered to have begun with the first and second Persian invasions of Greece at the start of the Greco-Persian wars, and to have ended with the death of Alexander the Great.
Classical Greek culture had a powerful influence on the Roman Empire, which carried a version of it to many parts of the Mediterranean region and Europe; thus Classical Greece is generally considered to be the seminal culture which provided the foundation of Western civilization. Language. Ancient Greek is the historical stage in the development of the Greek language spanning the Archaic ( to 6th centuries BC), Classical ( to 4th centuries BC), and Hellenistic ( century BC to 6th century AD) periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek. Its Hellenistic phase is known as Koine ("common") or Biblical Greek, and its late period mutates imperceptibly into Medieval Greek. Koine is regarded as a separate historical stage of its own, although in its earlier form it closely resembles Classical Greek. Prior to the Koine period, Greek of the classical and earlier periods included several regional dialects. Ancient Greek was the language of Homer and of classical Athenian historians, playwrights, and philosophers. It has contributed many words to the vocabulary of English and many other European languages, and has been a standard subject of study in Western educational institutions since the Renaissance. Latinized forms of Ancient Greek roots are used in many of the scientific names of species and in other scientific terminology.
Literature. The earliest surviving works of Greek literature are epic poetry. Homer's "Iliad" and "Odyssey" are the earliest to survive to us today, probably composed in the eighth century BC. These early epics were oral compositions, created without the use of writing. Around the same time that the Homeric epics were composed, the Greek alphabet was introduced; the earliest surviving inscriptions date from around 750 BC. European drama was invented in ancient Greece. Traditionally this was attributed to Thespis, around the middle of the sixth century BC, though the earliest surviving work of Greek drama is Aeschylus' tragedy "The Persians", which dates to 472 BC. Early Greek tragedy was performed by a chorus and two actors, but by the end of Aeschylus' life, a third actor had been introduced, either by him or by Sophocles. The last surviving Greek tragedies are the "Bacchae" of Euripides and Sophocles' Oedipus at Colonus, both from the end of the fifth century BC. Surviving Greek comedy begins later than tragedy; the earliest surviving work, Aristophanes' "Acharnians", comes from 425 BC. However, comedy dates back as early as 486 BC, when the Dionysia added a competition for comedy to the much earlier competition for tragedy. The comedy of the fifth century is known as Old Comedy, and it comes down to us solely in the eleven surviving plays of Aristophanes, along with a few fragments. Sixty years after the end of Aristophanes' career, the next author of comedies to have any substantial body of work survive is Menander, whose style is known as New Comedy.
Mythology and religion. Greek mythology is the body of myths and legends belonging to the ancient Greeks concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece. Modern scholars refer to the myths and study them in an attempt to throw light on the religious and political institutions of ancient Greece and its civilization, and to gain understanding of the nature of myth-making itself. Greek religion encompassed the collection of beliefs and rituals practiced in ancient Greece in the form of both popular public religion and cult practices. These different groups varied enough for it to be possible to speak of Greek religions or "cults" in the plural, though most of them shared similarities. Also, the Greek religion extended out of Greece and out to neighbouring islands. Many Greek people recognized the major gods and goddesses: Zeus, Poseidon, Hades, Apollo, Artemis, Aphrodite, Ares, Dionysus, Hephaestus, Athena, Hermes, Demeter, Hestia and Hera; though philosophies such as Stoicism and some forms of Platonism used language that seems to posit a transcendent single deity. Different cities often worshipped the same deities, sometimes with epithets that distinguished them and specified their local nature.
Philosophy. The earliest surviving philosophy from ancient Greece dates back to the 6th century BC, when according to Aristotle Thales of Miletus was considered to have been the first Greek philosopher. Other influential pre-Socratic philosophers include Pythagoras and Heraclitus. The most famous and significant figures in classical Athenian philosophy, from the 5th to the 3rd centuries BC, are Socrates, his student Plato, and Aristotle, who studied at Plato's Academy before founding his own school, known as the Lyceum. Later Greek schools of philosophy, including the Cynics, Stoics, and Epicureans, continued to be influential after the Roman annexation of Greece, and into the post-Classical world. Greek philosophy dealt with a wide variety of subjects, including political philosophy, ethics, metaphysics, ontology, and logic, as well as disciplines which are not today thought of as part of philosophy, such as biology and rhetoric. Classical Rome. Language. The language of ancient Rome was Latin, a member of the Italic family of languages. The earliest surviving inscription in Latin comes from the 7th century BC, on a brooch from Palestrina. Latin from between this point and the early 1st century BC is known as Old Latin. Most surviving Latin literature is Classical Latin, from the 1st century BC to the 2nd century AD. Latin then evolved into Late Latin, in use during the late antique period. Late Latin survived long after the end of classical antiquity, and was finally replaced by written Romance languages around the 9th century AD. Along with literary forms of Latin, there existed various vernacular dialects, generally known as Vulgar Latin, in use throughout antiquity. These are mainly preserved in sources such as graffiti and the Vindolanda tablets.
Literature. Latin literature seems to have started in 240 BC, when a Roman audience saw a play adapted from the Greek by Livius Andronicus. Andronicus also translated Homer's "Odyssey" into Saturnian verse. The poets Ennius, Accius, and Patruvius followed. Their work survives only in fragments; the earliest Latin authors whose work we have full examples of are the playwrights Plautus and Terence. Much of the best known and most highly thought of Latin literature comes from the classical period, with poets such as Virgil, Horace, and Ovid; historians such as Julius Caesar and Tacitus; orators such as Cicero; and philosophers such as Seneca the Younger and Lucretius. Late Latin authors include many Christian writers such as Lactantius, Tertullian and Ambrose; non-Christian authors, such as the historian Ammianus Marcellinus, are also preserved. History. According to legend, the city of Rome was founded in 753 BC; in reality, there had been a settlement on the site since around 1000 BC, when the Palatine Hill was settled. The city was originally ruled by kings, first Roman, and then Etruscanaccording to Roman tradition, the first Etruscan king of Rome, Tarquinius Priscus, ruled from 616 BC. Over the course of the 6th century BC, the city expanded its influence over the entirety of Latium. Around the end of the 6th century – traditionally in 510 BCthe kings of Rome were driven out, and the city became a republic.
Around 387 BC, Rome was sacked by the Gauls following the Battle of the Allia. It soon recovered from this humiliating defeat, however, and in 381 the inhabitants of Tusculum in Latium were made Roman citizens. This was the first time Roman citizenship was extended in this way. Rome went on to expand its area of influence, until by 269 the entirety of the Italian peninsula was under Roman rule. Soon afterwards, in 264, the First Punic War began; it lasted until 241. The Second Punic War began in 218, and by the end of that year, the Carthaginian general Hannibal had invaded Italy. The war saw Rome's worst defeat to that point at Cannae; the largest army Rome had yet put into the field was wiped out, and one of the two consuls leading it was killed. However, Rome continued to fight, annexing much of Spain and eventually defeating Carthage, ending her position as a major power and securing Roman preeminence in the Western Mediterranean. Legacy of the classical world. The classical languages of the ancient Mediterranean world influenced every European language, imparting to each a learned vocabulary of international application. Thus, Latin grew from a highly developed cultural product of the Golden and Silver eras of Latin literature to become the "international lingua franca" in matters diplomatic, scientific, philosophic and religious, until the 17th century. Long before this, Latin had evolved into the Romance languages and Ancient Greek into Modern Greek and its dialects. In the specialised science and technology vocabularies, the influence of Latin and Greek is notable. Ecclesiastical Latin, the Roman Catholic Church's official language, remains a living legacy of the classical world in the contemporary world.
Latin had an impact far beyond the classical world. It continued to be the pre-eminent language for serious writings in Europe long after the fall of the Roman Empire. The modern Romance languages (French, Italian, Portuguese, Romanian, Spanish, Galician, Catalan) all derive from Latin. Latin is still seen as a foundational aspect of European culture. The legacy of the classical world is not confined to the influence of classical languages. The Roman Empire was taken as a model by later European empires, such as the Spanish and British empires. Classical art has been taken as a model in later periods – medieval Romanesque architecture and Enlightenment-era neoclassical literature were both influenced by classical models, to take but two examples, while James Joyce's "Ulysses" is one of the most influential works of twentieth-century literature.
Chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the Moon (cosmochemistry), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).
Chemistry has existed under various names since ancient times. It has evolved, and now chemistry encompasses various areas of specialisation, or subdisciplines, that continue to increase in number and interrelate to create further interdisciplinary fields of study. The applications of various fields of chemistry are used frequently for economic purposes in the chemical industry. Etymology. The word "chemistry" comes from a modification during the Renaissance of the word "alchemy," which referred to an earlier set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism, and medicine. Alchemy is often associated with the quest to turn lead or other base metals into gold, though alchemists were also interested in many of the questions of modern chemistry. The modern word "alchemy" in turn is derived from the Arabic word (). This may have Egyptian origins since is derived from the Ancient Greek , which is in turn derived from the word , which is the ancient name of Egypt in the Egyptian language. Alternately, may derive from 'cast together'.
Modern principles. The current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, atoms, molecules, substances, metals, crystals and other aggregates of matter. Matter can be studied in solid, liquid, gas and plasma states, in isolation or in combination. The interactions, reactions and transformations that are studied in chemistry are usually the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together. Such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware. However glassware is not central to chemistry, and a great deal of experimental (as well as applied/industrial) chemistry is done without it. A chemical reaction is a transformation of some substances into one or more different substances. The basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which usually involves atoms as subjects. The number of atoms on the left and the right in the equation for a chemical transformation is equal. (When the number of atoms on either side is unequal, the transformation is referred to as a nuclear reaction or radioactive decay.) The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.
Energy and entropy considerations are invariably important in almost all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions. They can be analyzed using the tools of chemical analysis, e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; some of them are: Matter. In chemistry, matter is defined as anything that has rest mass and volume (it takes up space) and is made up of particles. The particles that make up matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a pure chemical substance or a mixture of substances. Atom. The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons. The nucleus is dense; the mass of a nucleon is approximately 1,836 times that of an electron, yet the radius of an atom is about 10,000 times that of its nucleus.
The atom is also the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state(s), coordination number, and preferred types of bonds to form (e.g., metallic, ionic, covalent). Element. A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol "Z". The mass number is the sum of the number of protons and neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same atomic number, they may not necessarily have the same mass number; atoms of an element which have different mass numbers are known as isotopes. For example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbon, but atoms of carbon may have mass numbers of 12 or 13. The standard presentation of the chemical elements is in the periodic table, which orders elements by atomic number. The periodic table is arranged in groups, or columns, and periods, or rows. The periodic table is useful in identifying periodic trends.
Compound. A "compound" is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements. The standard nomenclature of compounds is set by the International Union of Pure and Applied Chemistry (IUPAC). Organic compounds are named according to the organic nomenclature system. The names for inorganic compounds are created according to the inorganic nomenclature system. When a compound has more than one component, then they are divided into two classes, the electropositive and the electronegative components. In addition the Chemical Abstracts Service (CAS) has devised a method to index chemical substances. In this scheme each chemical substance is identifiable by a number known as its CAS registry number. Molecule. A "molecule" is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well for substances that are composed of molecules, which is not true of many substances (see below). Molecules are typically a set of atoms bound together by covalent bonds, such that the structure is electrically neutral and all valence electrons are paired with other electrons either in bonds or in lone pairs.
Thus, molecules exist as electrically neutral units, unlike ions. When this rule is broken, giving the "molecule" a charge, the result is sometimes named a molecular ion or a polyatomic ion. However, the discrete and separate nature of the molecular concept usually requires that molecular ions be present only in well-separated form, such as a directed beam in a vacuum in a mass spectrometer. Charged polyatomic collections residing in solids (for example, common sulfate or nitrate ions) are generally not considered "molecules" in chemistry. Some molecules contain one or more unpaired electrons, creating radicals. Most radicals are comparatively reactive, but some, such as nitric oxide (NO) can be stable. The "inert" or noble gas elements (helium, neon, argon, krypton, xenon and radon) are composed of lone atoms as their smallest discrete unit, but the other isolated chemical elements consist of either molecules or networks of atoms bonded to each other in some way. Identifiable molecules compose familiar substances such as water, air, and many organic compounds like alcohol, sugar, gasoline, and the various pharmaceuticals.
However, not all substances or chemical compounds consist of discrete molecules, and indeed most of the solid substances that make up the solid crust, mantle, and core of the Earth are chemical compounds without molecules. These other types of substances, such as ionic compounds and network solids, are organized in such a way as to lack the existence of identifiable molecules "per se". Instead, these substances are discussed in terms of formula units or unit cells as the smallest repeating structure within the substance. Examples of such substances are mineral salts (such as table salt), solids like carbon and diamond, metals, and familiar silica and silicate minerals such as quartz and granite. One of the main characteristics of a molecule is its geometry often called its structure. While the structure of diatomic, triatomic or tetra-atomic molecules may be trivial, (linear, angular pyramidal etc.) the structure of polyatomic molecules, that are constituted of more than six atoms (of several elements) can be crucial for its chemical nature.
Substance and mixture. A chemical substance is a kind of matter with a definite composition and set of properties. A collection of substances is called a mixture. Examples of mixtures are air and alloys. Mole and amount of substance. The mole is a unit of measurement that denotes an amount of substance (also called chemical amount). One mole is defined to contain exactly particles (atoms, molecules, ions, or electrons), where the number of particles per mole is known as the Avogadro constant. Molar concentration is the amount of a particular substance per volume of solution, and is commonly reported in mol/dm3. Phase. In addition to the specific chemical properties that distinguish different chemical classifications, chemicals can exist in several phases. For the most part, the chemical classifications are independent of these bulk phase classifications; however, some more exotic phases are incompatible with certain chemical properties. A "phase" is a set of states of a chemical system that have similar bulk structural properties, over a range of conditions, such as pressure or temperature.
Physical properties, such as density and refractive index tend to fall within values characteristic of the phase. The phase of matter is defined by the "phase transition", which is when energy put into or taken out of the system goes into rearranging the structure of the system, instead of changing the bulk conditions. Sometimes the distinction between phases can be continuous instead of having a discrete boundary; in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a set of conditions. The most familiar examples of phases are solids, liquids, and gases. Many substances exhibit multiple solid phases. For example, there are three phases of solid iron (alpha, gamma, and delta) that vary based on temperature and pressure. A principal difference between solid phases is the crystal structure, or arrangement, of the atoms. Another phase commonly encountered in the study of chemistry is the "aqueous" phase, which is the state of substances dissolved in aqueous solution (that is, in water).
Less familiar phases include plasmas, Bose–Einstein condensates and fermionic condensates and the paramagnetic and ferromagnetic phases of magnetic materials. While most familiar phases deal with three-dimensional systems, it is also possible to define analogs in two-dimensional systems, which has received attention for its relevance to systems in biology. Bonding. Atoms sticking together in molecules or crystals are said to be bonded with one another. A chemical bond may be visualized as the multipole balance between the positive charges in the nuclei and the negative charges oscillating about them. More than simple attraction and repulsion, the energies and distributions characterize the availability of an electron to bond to another atom. The chemical bond can be a covalent bond, an ionic bond, a hydrogen bond or just because of Van der Waals force. Each of these kinds of bonds is ascribed to some potential. These potentials create the interactions which hold atoms together in molecules or crystals. In many simple compounds, valence bond theory, the Valence Shell Electron Pair Repulsion model (VSEPR), and the concept of oxidation number can be used to explain molecular structure and composition.
An ionic bond is formed when a metal loses one or more of its electrons, becoming a positively charged cation, and the electrons are then gained by the non-metal atom, becoming a negatively charged anion. The two oppositely charged ions attract one another, and the ionic bond is the electrostatic force of attraction between them. For example, sodium (Na), a metal, loses one electron to become an Na+ cation while chlorine (Cl), a non-metal, gains this electron to become Cl−. The ions are held together due to electrostatic attraction, and that compound sodium chloride (NaCl), or common table salt, is formed. In a covalent bond, one or more pairs of valence electrons are shared by two atoms: the resulting electrically neutral group of bonded atoms is termed a molecule. Atoms will share valence electrons in such a way as to create a noble gas electron configuration (eight electrons in their outermost shell) for each atom. Atoms that tend to combine in such a way that they each have eight electrons in their valence shell are said to follow the octet rule. However, some elements like hydrogen and lithium need only two electrons in their outermost shell to attain this stable configuration; these atoms are said to follow the "duet rule", and in this way they are reaching the electron configuration of the noble gas helium, which has two electrons in its outer shell.
Similarly, theories from classical physics can be used to predict many ionic structures. With more complicated compounds, such as metal complexes, valence bond theory is less applicable and alternative approaches, such as the molecular orbital theory, are generally used. Energy. In the context of chemistry, energy is an attribute of a substance as a consequence of its atomic, molecular or aggregate structure. Since a chemical transformation is accompanied by a change in one or more of these kinds of structures, it is invariably accompanied by an increase or decrease of energy of the substances involved. Some energy is transferred between the surroundings and the reactants of the reaction in the form of heat or light; thus the products of a reaction may have more or less energy than the reactants. A reaction is said to be exergonic if the final state is lower on the energy scale than the initial state; in the case of endergonic reactions the situation is the reverse. A reaction is said to be exothermic if the reaction releases heat to the surroundings; in the case of endothermic reactions, the reaction absorbs heat from the surroundings.
Chemical reactions are invariably not possible unless the reactants surmount an energy barrier known as the activation energy. The "speed" of a chemical reaction (at given temperature T) is related to the activation energy E, by the Boltzmann's population factor formula_1 – that is the probability of a molecule to have energy greater than or equal to E at the given temperature T. This exponential dependence of a reaction rate on temperature is known as the Arrhenius equation. The activation energy necessary for a chemical reaction to occur can be in the form of heat, light, electricity or mechanical force in the form of ultrasound. A related concept free energy, which also incorporates entropy considerations, is a very useful means for predicting the feasibility of a reaction and determining the state of equilibrium of a chemical reaction, in chemical thermodynamics. A reaction is feasible only if the total change in the Gibbs free energy is negative, formula_2; if it is equal to zero the chemical reaction is said to be at equilibrium.
There exist only limited possible states of energy for electrons, atoms and molecules. These are determined by the rules of quantum mechanics, which require quantization of energy of a bound system. The atoms/molecules in a higher energy state are said to be excited. The molecules/atoms of substance in an excited energy state are often much more reactive; that is, more amenable to chemical reactions. The phase of a substance is invariably determined by its energy and the energy of its surroundings. When the intermolecular forces of a substance are such that the energy of the surroundings is not sufficient to overcome them, it occurs in a more ordered phase like liquid or solid as is the case with water (H2O); a liquid at room temperature because its molecules are bound by hydrogen bonds. Whereas hydrogen sulfide (H2S) is a gas at room temperature and standard pressure, as its molecules are bound by weaker dipole–dipole interactions. The transfer of energy from one chemical substance to another depends on the "size" of energy quanta emitted from one substance. However, heat energy is often transferred more easily from almost any substance to another because the phonons responsible for vibrational and rotational energy levels in a substance have much less energy than photons invoked for the electronic energy transfer. Thus, because vibrational and rotational energy levels are more closely spaced than electronic energy levels, heat is more easily transferred between substances relative to light or other forms of electronic energy. For example, ultraviolet electromagnetic radiation is not transferred with as much efficacy from one substance to another as thermal or electrical energy.
The existence of characteristic energy levels for different chemical substances is useful for their identification by the analysis of spectral lines. Different kinds of spectra are often used in chemical spectroscopy, e.g. IR, microwave, NMR, ESR, etc. Spectroscopy is also used to identify the composition of remote objects – like stars and distant galaxies – by analyzing their radiation spectra. The term chemical energy is often used to indicate the potential of a chemical substance to undergo a transformation through a chemical reaction or to transform other chemical substances. Reaction. When a chemical substance is transformed as a result of its interaction with another substance or with energy, a chemical reaction is said to have occurred. A "chemical reaction" is therefore a concept related to the "reaction" of a substance when it comes in close contact with another, whether as a mixture or a solution; exposure to some form of energy, or both. It results in some energy exchange between the constituents of the reaction as well as with the system environment, which may be designed vessels—often laboratory glassware.
Chemical reactions can result in the formation or dissociation of molecules, that is, molecules breaking apart to form two or more molecules or rearrangement of atoms within or across molecules. Chemical reactions usually involve the making or breaking of chemical bonds. Oxidation, reduction, dissociation, acid–base neutralization and molecular rearrangement are some examples of common chemical reactions. A chemical reaction can be symbolically depicted through a chemical equation. While in a non-nuclear chemical reaction the number and kind of atoms on both sides of the equation are equal, for a nuclear reaction this holds true only for the nuclear particles viz. protons and neutrons. The sequence of steps in which the reorganization of chemical bonds may be taking place in the course of a chemical reaction is called its mechanism. A chemical reaction can be envisioned to take place in a number of steps, each of which may have a different speed. Many reaction intermediates with variable stability can thus be envisaged during the course of a reaction. Reaction mechanisms are proposed to explain the kinetics and the relative product mix of a reaction. Many physical chemists specialize in exploring and proposing the mechanisms of various chemical reactions. Several empirical rules, like the Woodward–Hoffmann rules often come in handy while proposing a mechanism for a chemical reaction.
According to the IUPAC gold book, a chemical reaction is "a process that results in the interconversion of chemical species." Accordingly, a chemical reaction may be an elementary reaction or a stepwise reaction. An additional caveat is made, in that this definition includes cases where the interconversion of conformers is experimentally observable. Such detectable chemical reactions normally involve sets of molecular entities as indicated by this definition, but it is often conceptually convenient to use the term also for changes involving single molecular entities (i.e. 'microscopic chemical events'). Ions and salts. An "ion" is a charged species, an atom or a molecule, that has lost or gained one or more electrons. When an atom loses an electron and thus has more protons than electrons, the atom is a positively charged ion or cation. When an atom gains an electron and thus has more electrons than protons, the atom is a negatively charged ion or anion. Cations and anions can form a crystalline lattice of neutral salts, such as the Na+ and Cl− ions forming sodium chloride, or NaCl. Examples of polyatomic ions that do not split up during acid–base reactions are hydroxide (OH−) and phosphate (PO43−).
Plasma is composed of gaseous matter that has been completely ionized, usually through high temperature. Acidity and basicity. A substance can often be classified as an acid or a base. There are several different theories which explain acid–base behavior. The simplest is Arrhenius theory, which states that an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water. According to Brønsted–Lowry acid–base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction; by extension, a base is the substance which receives that hydrogen ion. A third common theory is Lewis acid–base theory, which is based on the formation of new chemical bonds. Lewis theory explains that an acid is a substance which is capable of accepting a pair of electrons from another substance during the process of bond formation, while a base is a substance which can provide a pair of electrons to form a new bond. There are several other ways in which a substance may be classified as an acid or a base, as is evident in the history of this concept.
Acid strength is commonly measured by two methods. One measurement, based on the Arrhenius definition of acidity, is pH, which is a measurement of the hydronium ion concentration in a solution, as expressed on a negative logarithmic scale. Thus, solutions that have a low pH have a high hydronium ion concentration and can be said to be more acidic. The other measurement, based on the Brønsted–Lowry definition, is the acid dissociation constant (Ka), which measures the relative ability of a substance to act as an acid under the Brønsted–Lowry definition of an acid. That is, substances with a higher Ka are more likely to donate hydrogen ions in chemical reactions than those with lower Ka values. Redox. Redox (-) reactions include all chemical reactions in which atoms have their oxidation state changed by either gaining electrons (reduction) or losing electrons (oxidation). Substances that have the ability to oxidize other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers. An oxidant removes electrons from another substance. Similarly, substances that have the ability to reduce other substances are said to be reductive and are known as reducing agents, reductants, or reducers.
A reductant transfers electrons to another substance and is thus oxidized itself. And because it "donates" electrons it is also called an electron donor. Oxidation and reduction properly refer to a change in oxidation number—the actual transfer of electrons may never occur. Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number. Equilibrium. Although the concept of equilibrium is widely used across sciences, in the context of chemistry, it arises whenever a number of different states of the chemical composition are possible, as for example, in a mixture of several chemical compounds that can react with one another, or when a substance can be present in more than one kind of phase. A system of chemical substances at equilibrium, even though having an unchanging composition, is most often not static; molecules of the substances continue to react with one another thus giving rise to a dynamic equilibrium. Thus the concept describes the state in which the parameters such as chemical composition remain unchanged over time.
Chemical laws. Chemical reactions are governed by certain laws, which have become fundamental concepts in chemistry. Some of them are: History. The history of chemistry spans a period from the ancient past to the present. Since several millennia BC, civilizations were using technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making glass, and making alloys like bronze. Chemistry was preceded by its protoscience, alchemy, which operated a non-scientific approach to understanding the constituents of matter and their interactions. Despite being unsuccessful in explaining the nature of matter and its transformations, alchemists set the stage for modern chemistry by performing experiments and recording the results. Robert Boyle, although skeptical of elements and convinced of alchemy, played a key part in elevating the "sacred art" as an independent, fundamental and philosophical discipline in his work "The Sceptical Chymist" (1661).
While both alchemy and chemistry are concerned with matter and its transformations, the crucial difference was given by the scientific method that chemists employed in their work. Chemistry, as a body of knowledge distinct from alchemy, became an established science with the work of Antoine Lavoisier, who developed a law of conservation of mass that demanded careful measurement and quantitative observations of chemical phenomena. The history of chemistry afterwards is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs. Definition. The definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term "chymistry", in the view of noted scientist Robert Boyle in 1661, meant the subject of the material principles of mixed bodies. In 1663, the chemist Christopher Glaser described "chymistry" as a scientific art, by which one learns to dissolve bodies, and draw from them the different substances on their composition, and how to unite them again, and exalt them to a higher perfection.
The 1730 definition of the word "chemistry", as used by Georg Ernst Stahl, meant the art of resolving mixed, compound, or aggregate bodies into their principles; and of composing such bodies from those principles. In 1837, Jean-Baptiste Dumas considered the word "chemistry" to refer to the science concerned with the laws and effects of molecular forces. This definition further evolved until, in 1947, it came to mean the science of substances: their structure, their properties, and the reactions that change them into other substances—a characterization accepted by Linus Pauling. More recently, in 1998, Professor Raymond Chang broadened the definition of "chemistry" to mean the study of matter and the changes it undergoes. Background. Early civilizations, such as the Egyptians, Babylonians, and Indians, amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but did not develop a systematic theory. A basic chemical hypothesis first emerged in Classical Greece with the theory of four elements as propounded definitively by Aristotle stating that fire, air, earth and water were the fundamental elements from which everything is formed as a combination. Greek atomism dates back to 440 BC, arising in works by philosophers such as Democritus and Epicurus. In 50 BCE, the Roman philosopher Lucretius expanded upon the theory in his poem "De rerum natura" (On The Nature of Things). Unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments.
An early form of the idea of conservation of mass is the notion that "Nothing comes from nothing" in Ancient Greek philosophy, which can be found in Empedocles (approx. 4th century BC): "For it is impossible for anything to come to be from what is not, and it cannot be brought about or heard of that what is should be utterly destroyed." and Epicurus (3rd century BC), who, describing the nature of the Universe, wrote that "the totality of things was always such as it is now, and always will be". In the Hellenistic world the art of alchemy first proliferated, mingling magic and occultism into the study of natural substances with the ultimate goal of transmuting elements into gold and discovering the elixir of eternal life. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. Alchemy continued to be developed and practised throughout the Arab world after the Muslim conquests, and from there, and from the Byzantine remnants, diffused into medieval and Renaissance Europe through Latin translations.
The Arabic works attributed to Jabir ibn Hayyan introduced a systematic classification of chemical substances, and provided instructions for deriving an inorganic compound (sal ammoniac or ammonium chloride) from organic substances (such as plants, blood, and hair) by chemical means. Some Arabic Jabirian works (e.g., the "Book of Mercy", and the "Book of Seventy") were later translated into Latin under the Latinized name "Geber", and in 13th-century Europe an anonymous writer, usually referred to as pseudo-Geber, started to produce alchemical and metallurgical writings under this name. Later influential Muslim philosophers, such as Abū al-Rayhān al-Bīrūnī and Avicenna disputed the theories of alchemy, particularly the theory of the transmutation of metals. Improvements of the refining of ores and their extractions to smelt metals was widely used source of information for early chemists in the 16th century, among them Georg Agricola (1494–1555), who published his major work "De re metallica" in 1556. His work, describing highly developed and complex processes of mining metal ores and metal extraction, were the pinnacle of metallurgy during that time. His approach removed all mysticism associated with the subject, creating the practical base upon which others could and would build. The work describes the many kinds of furnaces used to smelt ore, and stimulated interest in minerals and their composition. Agricola has been described as the "father of metallurgy" and the founder of geology as a scientific discipline.
Under the influence of the new empirical methods propounded by Sir Francis Bacon and others, a group of chemists at Oxford, Robert Boyle, Robert Hooke and John Mayow began to reshape the old alchemical traditions into a scientific discipline. Boyle in particular questioned some commonly held chemical theories and argued for chemical practitioners to be more "philosophical" and less commercially focused in "The Sceptical Chemyst". He formulated Boyle's law, rejected the classical "four elements" and proposed a mechanistic alternative of atoms and chemical reactions that could be subject to rigorous experiment. In the following decades, many important discoveries were made, such as the nature of 'air' which was discovered to be composed of many different gases. The Scottish chemist Joseph Black and the Flemish Jan Baptist van Helmont discovered carbon dioxide, or what Black called 'fixed air' in 1754; Henry Cavendish discovered hydrogen and elucidated its properties and Joseph Priestley and, independently, Carl Wilhelm Scheele isolated pure oxygen. The theory of phlogiston (a substance at the root of all combustion) was propounded by the German Georg Ernst Stahl in the early 18th century and was only overturned by the end of the century by the French chemist Antoine Lavoisier, the chemical analogue of Newton in physics. Lavoisier did more than any other to establish the new science on proper theoretical footing, by elucidating the principle of conservation of mass and developing a new system of chemical nomenclature used to this day.
English scientist John Dalton proposed the modern theory of atoms; that all substances are composed of indivisible 'atoms' of matter and that different atoms have varying atomic weights. The development of the electrochemical theory of chemical combinations occurred in the early 19th century as the result of the work of two scientists in particular, Jöns Jacob Berzelius and Humphry Davy, made possible by the prior invention of the voltaic pile by Alessandro Volta. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current. British William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. J.A.R. Newlands devised an early table of elements, which was then developed into the modern periodic table of elements in the 1860s by Dmitri Mendeleev and independently by several other scientists including Julius Lothar Meyer. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table.
Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhler's synthesis of urea. Other crucial 19th century advances were; an understanding of valence bonding (Edward Frankland in 1852) and the application of thermodynamics to chemistry (J. W. Gibbs and Svante Arrhenius in the 1870s). At the turn of the twentieth century the theoretical underpinnings of chemistry were finally understood due to a series of remarkable discoveries that succeeded in probing and discovering the very nature of the internal structure of atoms. In 1897, J.J. Thomson of the University of Cambridge discovered the electron and soon after the French scientist Becquerel as well as the couple Pierre and Marie Curie investigated the phenomenon of radioactivity. In a series of pioneering scattering experiments Ernest Rutherford at the University of Manchester discovered the internal structure of the atom and the existence of the proton, classified and explained the different types of radioactivity and successfully transmuted the first element by bombarding nitrogen with alpha particles.
His work on atomic structure was improved on by his students, the Danish physicist Niels Bohr, the Englishman Henry Moseley and the German Otto Hahn, who went on to father the emerging nuclear chemistry and discovered nuclear fission. The electronic theory of chemical bonds and molecular orbitals was developed by the American scientists Linus Pauling and Gilbert N. Lewis. The year 2011 was declared by the United Nations as the International Year of Chemistry. It was an initiative of the International Union of Pure and Applied Chemistry, and of the United Nations Educational, Scientific, and Cultural Organization and involves chemical societies, academics, and institutions worldwide and relied on individual initiatives to organize local and regional activities. Practice. In the practice of chemistry, pure chemistry is the study of the fundamental principles of chemistry, while applied chemistry applies that knowledge to develop technology and solve real-world problems. Subdisciplines. Chemistry is typically divided into several major sub-disciplines. There are also several main cross-disciplinary and more specialized fields of chemistry.
Other subdivisions include electrochemistry, femtochemistry, flavor chemistry, flow chemistry, immunohistochemistry, hydrogenation chemistry, mathematical chemistry, molecular mechanics, natural product chemistry, organometallic chemistry, petrochemistry, photochemistry, physical organic chemistry, polymer chemistry, radiochemistry, sonochemistry, supramolecular chemistry, synthetic chemistry, and many others. Interdisciplinary. Interdisciplinary fields include agrochemistry, astrochemistry (and cosmochemistry), atmospheric chemistry, chemical engineering, chemical biology, chemo-informatics, environmental chemistry, geochemistry, green chemistry, immunochemistry, marine chemistry, materials science, mechanochemistry, medicinal chemistry, molecular biology, nanotechnology, oenology, pharmacology, phytochemistry, solid-state chemistry, surface science, thermochemistry, and many others. Industry. The chemical industry represents an important economic activity worldwide. The global top 50 chemical producers in 2013 had sales of US$980.5 billion with a profit margin of 10.3%. Further reading. Popular reading Introductory undergraduate textbooks Advanced undergraduate-level or graduate textbooks
Cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the cell's internal sub-structures, and various cytoplasmic inclusions. In eukaryotes the cytoplasm also includes the nucleus, and other membrane-bound organelles.The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance, or cytoplasmic matrix, that remains after the exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, plant plastids, lipid droplets, and vacuoles. Many cellular activities take place within the cytoplasm, such as many metabolic pathways, including glycolysis, photosynthesis, and processes such as cell division. The concentrated inner area is called the endoplasm and the outer layer is called the cell cortex, or ectoplasm.
Movement of calcium ions in and out of the cytoplasm is a signaling activity for metabolic processes. In plants, movement of the cytoplasm around vacuoles is known as cytoplasmic streaming. History. The term was introduced by Rudolf von Kölliker in 1863, originally as a synonym for protoplasm, but later it has come to mean the cell substance and organelles outside the nucleus. There has been certain disagreement on the definition of cytoplasm, as some authors prefer to exclude from it some organelles, especially the vacuoles and sometimes the plastids. Physical nature. It remains uncertain how the various components of the cytoplasm interact to allow movement of organelles while maintaining the cell's structure. The flow of cytoplasmic components plays an important role in many cellular functions which are dependent on the permeability of the cytoplasm. An example of such function is cell signalling, a process which is dependent on the manner in which signaling molecules are allowed to diffuse across the cell. While small signaling molecules like calcium ions are able to diffuse with ease, larger molecules and subcellular structures often require aid in moving through the cytoplasm. The irregular dynamics of such particles have given rise to various theories on the nature of the cytoplasm.
As a sol-gel. There has long been evidence that the cytoplasm behaves like a sol-gel. It is thought that the component molecules and structures of the cytoplasm behave at times like a disordered colloidal solution (sol) and at other times like an integrated network, forming a solid mass (gel). This theory thus proposes that the cytoplasm exists in distinct fluid and solid phases depending on the level of interaction between cytoplasmic components, which may explain the differential dynamics of different particles observed moving through the cytoplasm. A papers suggested that at length scale smaller than 100 nm, the cytoplasm acts like a liquid, while in a larger length scale, it acts like a gel. As a glass. It has been proposed that the cytoplasm behaves like a glass-forming liquid approaching the glass transition. In this theory, the greater the concentration of cytoplasmic components, the less the cytoplasm behaves like a liquid and the more it behaves as a solid glass, freezing more significant cytoplasmic components in place (it is thought that the cell's metabolic activity can fluidize the cytoplasm to allow the movement of such more significant cytoplasmic components). A cell's ability to vitrify in the absence of metabolic activity, as in dormant periods, may be beneficial as a defense strategy. A solid glass cytoplasm would freeze subcellular structures in place, preventing damage, while allowing the transmission of tiny proteins and metabolites, helping to kickstart growth upon the cell's revival from dormancy.
Other perspectives. Research has examined the motion of cytoplasmic particles independent of the nature of the cytoplasm. In such an alternative approach, the aggregate random forces within the cell caused by motor proteins explain the non-Brownian motion of cytoplasmic constituents. Constituents. The three major elements of the cytoplasm are the cytosol, organelles and inclusions. Cytosol. The cytosol is the portion of the cytoplasm not contained within membrane-bound organelles. Cytosol makes up about 70% of the cell volume and is a complex mixture of cytoskeleton filaments, dissolved molecules, and water. The cytosol's filaments include the protein filaments such as actin filaments and microtubules that make up the cytoskeleton, as well as soluble proteins and small structures such as ribosomes, proteasomes, and the mysterious vault complexes. The inner, granular and more fluid portion of the cytoplasm is referred to as endoplasm. Due to this network of fibres and high concentrations of dissolved macromolecules, such as proteins, an effect called macromolecular crowding occurs and the cytosol does not act as an ideal solution. This crowding effect alters how the components of the cytosol interact with each other.
Organelles. Organelles (literally "little organs") are usually membrane-bound structures inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the mitochondria, the endoplasmic reticulum, the Golgi apparatus, vacuoles, lysosomes, and in plant cells, chloroplasts. Cytoplasmic inclusions. The inclusions are small particles of insoluble substances suspended in the cytosol. A huge range of inclusions exist in different cell types, and range from crystals of calcium oxalate or silicon dioxide in plants, to granules of energy-storage materials such as starch, glycogen, or polyhydroxybutyrate. A particularly widespread example are lipid droplets, which are spherical droplets composed of lipids and proteins that are used in both prokaryotes and eukaryotes as a way of storing lipids such as fatty acids and sterols. Lipid droplets make up much of the volume of adipocytes, which are specialized lipid-storage cells, but they are also found in a range of other cell types.
Controversy and research. The cytoplasm, mitochondria, and most organelles are contributions to the cell from the maternal gamete. Contrary to the older information that disregards any notion of the cytoplasm being active, new research has shown it to be in control of movement and flow of nutrients in and out of the cell by viscoplastic behavior and a measure of the reciprocal rate of bond breakage within the cytoplasmic network. The material properties of the cytoplasm remain an ongoing investigation. A method of determining the mechanical behaviour of living cell mammalian cytoplasm with the aid of optical tweezers has been described.
Christ (title) Christ, used by Christians as both a name and a title, unambiguously refers to Jesus. It is also used as a title, in the reciprocal usage "Christ Jesus", meaning "the Messiah Jesus" or "Jesus the Anointed", and independently as "the Christ". The Pauline epistles, the earliest texts of the New Testament, often call Jesus "Christ Jesus" or just "Christ". The concept of the Christ in Christianity originated from the concept of the messiah in Judaism. Christians believe that Jesus is the messiah foretold in the Hebrew Bible and the Christian Old Testament. Although the conceptions of the messiah in each religion are similar, for the most part they are distinct from one another due to the split of early Christianity and Judaism in the 1st century. Although the original followers of Jesus believed Jesus to be the Jewish messiah, e.g. in the Confession of Peter, he was usually called "Jesus of Nazareth" or "Jesus, son of Joseph". Jesus came to be called "Jesus Christ" (meaning "Jesus the "Khristós"", i.e. "Jesus the Messiah" or "Jesus the Anointed") by Christians, who believe that his crucifixion and resurrection fulfill the messianic prophecies of the Old Testament, especially the prophecies outlined in Isaiah 53 and Psalm 22.
Etymology. "Christ" derives from the Greek word (), meaning "anointed one". The word is derived from the Greek verb (), meaning "to anoint." In the Greek Septuagint, "χριστός" was a semantic loan used to translate the Hebrew (, messiah), meaning "[one who is] anointed". Usage. The word "Christ" (and similar spellings) appears in English and in most European languages. English speakers now often use "Christ" as if it were a name, one part of the name "Jesus Christ", though it was originally a title ("the Messiah"). Its usage in "Christ Jesus" emphasizes its nature as a title. Compare the usage "the Christ". The spelling "Christ" in English became standardized in the 18th century, when, in the spirit of the Enlightenment, certain words' spelling changed to fit their Greek or Latin origins. Before that, scribes writing in Old and Middle English usually used the spelling "Crist"—the "i" being pronounced either as , preserved in the names of churches such as St Katherine Cree, or as a short , preserved in the modern pronunciation of "Christmas". The spelling "Christ" in English is attested from the 14th century.
In modern and ancient usage, even in secular terminology, "Christ" usually refers to Jesus, based on the centuries-old tradition of such usage. Since the Apostolic Age, the use of the definite article before the word "Christ" and its gradual development into a proper name show the Christians identified the bearer with the promised messiah of the Jews. Background and New Testament references. Pre–New-Testament references. In the Old Testament, anointing was a ceremonial ritual reserved to: In the Septuagint text of the deuterocanonical books, the term "Christ" (Χριστός, translit. Christós) is found in 2 Maccabees 1:10 (referring to the anointed High Priest of Israel) and in the Book of Sirach 46:19, in relation to Samuel, prophet and institutor of the kingdom under Saul. At the time of Jesus, there was no single form of Second Temple Judaism, and there were significant political, social, and religious differences among the various Jewish groups. But for centuries the Jews had used the term "moshiach" ("anointed") to refer to their expected deliverer.
Opening lines of Mark and Matthew. Mark ("The beginning of the gospel of Jesus Christ, the Son of God") identifies Jesus as both Christ and the Son of God. uses Christ as a name and Matthew explains it again with: "Jesus, who is called Christ". The use of the definite article before the word "Christ" and its gradual development into a proper name show that the Christians identified Jesus with the promised messiah of the Jews who fulfilled all the messianic predictions in a fuller and a higher sense than had been given them by the rabbis. Confession of Peter (Matthew, Mark and Luke). The so-called Confession of Peter, recorded in the Synoptic Gospels as Jesus's foremost apostle Peter saying that Jesus was the Messiah, has become a famous proclamation of faith among Christians since the first century. Martha's statement (John). In Martha told Jesus, "you are the Christ, the Son of God, who is coming into the world", signifying that both titles were generally accepted (yet considered distinct) among the followers of Jesus before the raising of Lazarus.
Sanhedrin trial of Jesus (Matthew, Mark and Luke). During the Sanhedrin trial of Jesus, it might appear from the narrative of Matthew that Jesus at first refused a direct reply to the high priest Caiaphas's question: "Are you the Messiah, the Son of God?", where his answer is given merely as Σὺ εἶπας ("Su eipas", "You [singular] have said it"). Similarly but differently in Luke, all those present are said to ask Jesus: 'Are you then the Son of God?', to which Jesus reportedly answered: Ὑμεῖς λέγετε ὅτι ἐγώ εἰμι ("Hymeis legete hoti ego eimi", "You [plural] say that I am". In the Gospel of Mark, however, when asked by Caiaphas 'Are you the Messiah, the Son of the Blessed One?', Jesus tells the Sanhedrin: Ἐγώ εἰμι ("ego eimi", "I am"). There are instances from Jewish literature in which the expression "you have said it" is equivalent to "you are right". The Messianic claim was less significant than the claim to divinity, which caused the high priest's horrified accusation of blasphemy and the subsequent call for the death sentence. Before Pilate, on the other hand, it was merely the assertion of his royal dignity which gave grounds for his condemnation.
Pauline epistles. The word "Christ" is closely associated with Jesus in the Pauline epistles, which suggests that there was no need for the early Christians to claim that Jesus is Christ because it was considered widely accepted among them. Hence Paul can use the term "Khristós" with no confusion as to whom it refers, and he can use expressions such as "in Christ" to refer to the followers of Jesus, as in and . Paul proclaimed him as the Last Adam, who restored through obedience what Adam lost through disobedience. The Pauline epistles are a source of some key Christological connections; e.g., relates the love of Christ to the knowledge of Christ, and considers the love of Christ as a necessity for knowing him. There are also implicit claims to him being the Christ in the words and actions of Jesus. Use of "Messias" in John. The Hellenization Μεσσίας (Messías) is used twice to mean "Messiah" in the New Testament: by the disciple Andrew at , and by the Samaritan woman at the well at John 4:25. In both cases, the Greek text specifies immediately after that this means "the Christ."
Christology. Christology, literally "the understanding of Christ", is the study of the nature (person) and work (role in salvation) of Jesus in Christianity. It studies Jesus Christ's humanity and divinity, and the relation between these two aspects; and the role he plays in salvation. From the second to the fifth centuries, the relation of the human and divine nature of Christ was a major focus of debates in the early church and at the first seven ecumenical councils. The Council of Chalcedon in 451 issued a formulation of the hypostatic union of the two natures of Christ, one human and one divine, "united with neither confusion nor division". Most of the major branches of Western Christianity and Eastern Orthodoxy subscribe to this formulation, while many branches of Oriental Orthodox Churches reject it, subscribing to miaphysitism. According to the "Summa Theologica" of Thomas Aquinas, in the singular case of Jesus, the word "Christ" has a twofold meaning, which stands for "both the Godhead anointing and the manhood anointed". It derives from the twofold human-divine nature of Christ (dyophysitism): the Son of man is anointed in consequence of His incarnated flesh, as well as the Son of God is anointing in consequence of the "Godhead which He has with the Father" (ST "III", q. 16, a. 5).
Symbols. The use of "Χ" as an abbreviation for "Christ" derives from the Greek letter Chi (χ), in the word (). An early Christogram is the "Chi Rho" symbol, formed by superimposing the first two Greek letters in Christ, chi (Χ) and rho (Ρ), to produce ☧. The centuries-old English word "Χmas" (or, in earlier form, "XPmas") is an English form of χ-mas, itself an abbreviation for Christ-mas. The "Oxford English Dictionary" ("OED") and the "OED Supplement" have cited usages of "X-" or "Xp-" for "Christ-" as early as 1485. The terms "Xpian" and "Xren" have been used for "Christian", "Xst" for "Christ's" "Xρofer" for (Saint) Christopher and Xmas, Xstmas, and Xtmas for Christmas. The "OED" further cites usage of "Xtianity" for "Christianity" from 1634. According to "Merriam-Webster's Dictionary of English Usage", most of the evidence for these words comes from "educated Englishmen who knew their Greek". The December 1957 "News and Views" published by the Church League of America, a conservative organization founded in 1937, attacked the use of "Xmas" in an article titled "X=The Unknown Quantity". Gerald L. K. Smith picked up the statements later, in December 1966, saying that Xmas was a "blasphemous omission of the name of Christ" and that "'X' is referred to as being symbolical of the unknown quantity." More recently, American evangelist Franklin Graham and former CNN contributor Roland S. Martin publicly raised concerns. Graham stated in an interview that the use of "Xmas" is taking "Christ out of Christmas" and called it a "war against the name of Jesus Christ." Roland Martin relates the use of "Xmas" to his growing concerns of increasing commercialization and secularization of what he says is one of Christianity's highest holy days.
Capital Capital and its variations may refer to:
Central Europe Central Europe is a geographical region of Europe between Eastern, Southern, Western and Northern Europe. Central Europe is known for its cultural diversity; however, countries in this region also share some historical and cultural similarities. Whilst the region is variously defined, it often includes Austria, Croatia, the Czech Republic, Germany, Hungary, Liechtenstein, Lithuania, Poland, Slovakia, Slovenia, Switzerland, Transylvania in Romania and Vojvodina in Serbia. From the early 16th century until the early 18th century, parts of Croatia, Hungary and Transylvania were ruled by the Turkish Empire. During the 17th century, the empire also occupied southern parts of present-day Slovakia. During the Early Modern period, the territories of Poland and Lithuania were part of the Polish–Lithuanian Commonwealth. Meanwhile, the Archduchy of Austria, the Kingdom of Bohemia (Czech Republic), the Duchy of Carniola (part of present-day Slovenia), the various German Principalities and the Old Swiss Confederacy were within the Holy Roman Empire. By the end of the 18th century, the Habsburg monarchy, a prominent power within the Holy Roman Empire, came to reign over the territories of Austria, Bosnia and Herzegovina, Croatia, the Czech Republic, Hungary, Slovakia and Slovenia, alongside parts of Serbia, Germany, Italy, Poland and Switzerland. Between the early 18th and early 20th centuries, Central Europe had a substantial Jewish population.
Since the Cold War the countries that make up Central Europe have historically been, and in some cases continue to be, divided into either Eastern or Western Europe. After World War II, Europe was divided by the Iron Curtain into two parts, the capitalist Western Bloc and the socialist Eastern Bloc, although Austria, Switzerland and Yugoslavia (encompassing the territories of present-day Croatia, Slovenia and various other Balkan nations) declared neutrality. The Berlin Wall was one of the most visible symbols of this division. Respectively, countries in Central Europe have historical, cultural and geopolitical ties with these wider regions of Europe. Central Europe began a "strategic awakening" in the late 20th and early 21st century, with initiatives such as the Central European Defence Cooperation, the Central European Initiative, Centrope, and the Visegrád Four Group. This awakening was accelerated by writers and other intellectuals, who recognized the societal paralysis of decaying dictatorships and felt compelled to speak up against Soviet oppression.
Historical perspective. Middle Ages and early modern period. In the early Middle Ages, Central Europe had a diverse landscape, with various ethnic groups inhabiting the region. Germanic tribes, among them the Franks, Alemans and Bavarians, were predominantly situated in the west, while Slavic tribes were predominantly in the east. However, the region encompassed a wide spectrum of additional tribes and communities. From the late 6th century to the early 9th century, the area roughly corresponding to the Carpathian Basin was part of the Avar Khaganate, the realm of the Pannonian Avars. While the Avars dominated the east of what is now Austria, its north and south were under Germanic and Slavic influence, respectively. Meanwhile, the territories now comprising Germany and Switzerland were under the influence of the Merovingian dynasty, and later the Carolingian dynasty. Various Slavic tribes that inhabited eastern Central Europe established settlements during this period, primarily in present-day Croatia, Czech Republic, Poland, Slovakia and Slovenia. The territory of Lithuania was inhabited by Baltic tribes. Amongst them were the Samogitians, Lithuanians and Curonians.
The Holy Roman Empire was founded at the turn of the 9th century, following the coronation of Charlemagne by Pope Leo III. At its inception, it incorporated present-day Germany and nearby regions, including parts of what is now Austria, the Czech Republic, Slovenia and Switzerland. Three decades later, Great Moravia, centred in present-day Czech Republic and Slovakia, became one of the first West Slavic states to be founded in Central Europe. In the late 9th Century, the Hungarian tribes, originating in parts of Asia along the east Eurasian Steppe, settled in the Carpathian Basin and established the Principality of Hungary. The earliest recorded concept of Europe as a cultural sphere (instead of simply a geographic term) was formed by Alcuin of York in the late 8th century during the Carolingian Renaissance, limited to the territories that practised Western Christianity at the time. "European" as a cultural term did not include much of the territories where the Orthodox Church represented the dominant religion until the 19th century.
Following the Christianization of various Central European countries, elements of cultural unity emerged within the region, specifically Catholicism and Latin. Eastern Europe remained Eastern Orthodox, and was dominated by Byzantine cultural influence. After the East–West Schism in 1054, significant parts of Eastern Europe developed cultural unity and resistance to Catholic Western and Central Europe within the framework of the Eastern Orthodox Church, Church Slavonic language and the Cyrillic alphabet. According to historian Jenő Szűcs, at the end of the first millennium Central Europe became influenced by Western European developments. Szűcs argued that between the 11th and 15th centuries, not only did Christianization influence the cultures within Central Europe, but well-defined social features were also implemented in the region based on Western characteristics. The keyword of Western social development after the turn of the millennium was the spread of Magdeburg rights in some cities and towns of Western Europe. These began to spread in the middle of the 13th century in Central European countries, bringing about self-governments of towns and counties.
In 1335, the Kings of Poland, Bohemia and Hungary and Croatia met in the castle of Visegrád and agreed to cooperate closely in the field of politics and commerce, inspiring the post-Cold War Visegrád Group. In 1386, Jogaila, the Grand Duke of Lithuania, converted to Christianity (specifically Catholicism) and subsequently became King of Poland through marriage to Queen Jadwiga of Poland. This initiated the Christianization of Lithuania. It also resulted in the Union of Krewo, signifying a personal union between the Grand Duchy of Lithuania and the Kingdom of Poland. The union commenced an enduring political alliance between the two entities and laid the foundations for the later establishment of the Polish-Lithuanian Commonwealth in 1569. Between the 15th and early 16th centuries, the Kingdom of Croatia, which was at the time in personal union with the Kingdom of Hungary, served as a significant maritime gateway of Central Europe, with its ports facilitating key trade routes between Central Europe and the Mediterranean. The Republic of Ragusa emerged as a prominent hub for cultural exchange during this time. Following the Ottoman and Habsburg wars of the 16th and 17th centuries, the Kingdom of Croatia, under Habsburg rule, began to regain its position as a significant trade route, restoring ports and revitalising commercial activity.
Before World War I. Before 1870, the industrialization that had started to develop in Northwestern and Central Europe and the United States did not extend in any significant way to the rest of the world. Even in Eastern Europe, industrialization lagged far behind. Russia, for example, remained largely rural and agricultural, and its autocratic rulers kept the peasants in serfdom. The concept of Central Europe was already known at the beginning of the 19th century, but it developed further and became an object of intensive interest towards the 20th century. However, the first concept mixed science, politics, and economy – it was strictly connected with the aspirations of German states to dominate a part of European continent called "Mitteleuropa". At the Frankfurt Parliament, which was established in the wake of the March Revolution of 1848, there were multiple competing ideas for the integration of German-speaking areas, including the "mitteleuropäische Lösung" (Central European Solution) propagated by Austria, which sought to merge the smaller German-speaking states with the multi-ethnic Habsburg Empire, but was opposed by Prussia and others. An imperialistic idea of "Mitteleuropa" also became popular in the German Empire established in 1871, which experienced intensive economic growth. The term was used when the Union of German Railway Administrations established the "Mitteleuropäische Eisenbahn-Zeit" (Central European Railway Time) time zone, which was applied by the railways from 1 June 1891 and was later widely adopted in civilian life, thus the time zone name shortened to the present-day Central European Time.
The German term denoting Central Europe was so fashionable that other languages started referring to it when indicating territories from Rhine to Vistula, or even Dnieper, and from the Baltic Sea to the Balkans. An example of this vision of Central Europe may be seen in Joseph Partsch's book of 1903. On 21 January 1904, "Mitteleuropäischer Wirtschaftsverein" (Central European Economic Association) was established in Berlin with economic integration of Germany and Austria (with eventual extension to Switzerland, Belgium and the Netherlands) as its main aim. Another time, the term Central Europe became connected to the German plans of political, economic, and cultural domination. The "bible" of the concept was Friedrich Naumann's book "Mitteleuropa" in which he called for an economic federation to be established after World War I. Naumann's proposed a federation with Germany and the Habsburg empire as its centre, eventually uniting all external European nations through economic prosperity. The concept failed after the German defeat in World War I. The revival of the idea may be observed during the Hitler era.
Interwar period. The interwar period (1918–1938) brought a new geopolitical system, as well as economic and political problems, and the concept of Central Europe took on a different character. The centre of interest was moved to its eastern part – particularly to the countries that had (re)appeared on the map of Europe. Central Europe ceased to be the area of German aspiration to lead or dominate and became a territory of various integration movements aiming at resolving political, economic, and national problems of "new" states, being a way to face German and Soviet pressures. However, the conflict of interests was too big and neither Little Entente nor Intermarium ("Międzymorze") ideas succeeded. Hungarian historian Magda Ádám wrote in her study "Versailles System and Central Europe" (2006): "Today we know that the bane of Central Europe was the Little Entente, military alliance of Czechoslovakia, Romania and Kingdom of Serbs, Croats and Slovenes (later Yugoslavia), created in 1921 not for Central Europe's cooperation nor to fight German expansion, but in a wrong perceived notion that a completely powerless Hungary must be kept down". The events preceding World War II in Europe—including the so-called Western betrayal/ Munich Agreement were very much enabled by the rising nationalism and ethnocentrism that typified that period.
The interwar period brought new elements to the concept of Central Europe. Before World War I, it embraced mainly German-speaking states, with non-German speaking territories being an area of intended German penetration and domination – German leadership was to be the 'natural' result of economic dominance. Post-war, the Eastern part of Central Europe was placed at the centre of the concept. At that time the scientists took an interest in the idea: the International Historical Congress in Brussels in 1923 was committed to Central Europe, and the 1933 Congress continued the discussions. According to Emmanuel de Martonne, in 1927, Central Europe encompassed Austria, Czechoslovakia, Germany, Hungary, Poland, Romania and Switzerland, northern Italy and northern Yugoslavia. The author uses both Human and Physical Geographical features to define Central Europe, but he doesn't take into account the legal development or the social, cultural, economic, and infrastructural developments in these countries. The avant-garde movements of Central Europe contributed to the evolution of modernism, reaching its peak throughout the continent during the 1920s. The "Sourcebook of Central European avantgards" (Los Angeles County Museum of Art) contains primary documents of the avant-gardes in the territories of Austria, Germany, Poland (including western parts of present-day Belarus and Ukraine, and southern parts of Lithuania), Czechoslovakia (including the Czech Republic and Slovakia), Hungary, Romania and Yugoslavia (including present-day Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, Serbia and Slovenia) from 1910 to 1930.
Mitteleuropa. With the dissolution of the Holy Roman Empire around 1800, there was a consolidation of power among the Habsburgs and Hohenzollerns as the two major states in the area. They had much in common and occasionally cooperated in various channels, but more often competed. One approach in the various attempts at cooperation, was the conception of a set of supposed common features and interests, and this idea led to the first discussions of a "Mitteleuropa" in the mid-nineteenth century, as espoused by Friedrich List and Karl Ludwig Bruck. These were mostly based on economic issues. "Mitteleuropa" may refer to a historical concept or a contemporary German definition of Central Europe. As a historical concept, the German term "Mitteleuropa" (or alternatively its literal translation into English, "Middle Europe") is an ambiguous German concept. According to Fritz Fischer "Mitteleuropa" was a scheme in the era of the Reich of 1871–1918 by which the old imperial elites had allegedly sought to build a system of German economic, military and political domination from the northern seas to the Near East and from the Low Countries through the steppes of Russia to the Caucasus. Later on, professor Fritz Epstein argued the threat of a Slavic "Drang nach Westen" (Western expansion) had been a major factor in the emergence of a "Mitteleuropa" ideology before the Reich of 1871 ever came into being.
In Germany the connotation was also sometimes linked to the pre-war German provinces east of the Oder-Neisse line. The term "Mitteleuropa" conjures up negative historical associations among some people, although the Germans have not played an exclusively negative role in the region. Most Central European Jews embraced the enlightened German humanistic culture of the 19th century. Jews of turn of the 20th century Central Europe became representatives of what many consider to be Central European culture at its best, though the Nazi conceptualisation of "Mitteleuropa" sought to destroy this culture. The term "Mitteleuropa" is widely used in German education and media without negative meaning, especially since the end of communism. Many people from the new states of Germany do not identify themselves as being part of Western Europe and therefore prefer the term "Mitteleuropa". Central Europe during World War II.
Central Europe behind the Iron Curtain. Following World War II, parts of Central Europe became part of the Eastern Bloc. The boundary between the two blocks was called the Iron Curtain. Austria, Switzerland and Yugoslavia remained neutral. The post-World War II period brought blocking of research on Central Europe in the Eastern Bloc countries, as its every result proved the dissimilarity of Central Europe, which was inconsistent with the Stalinist doctrine. On the other hand, the topic became popular in Western Europe and the United States, much of the research being carried out by immigrants from Central Europe. Following the Fall of Communism, publicists and historians in Central Europe, especially the anti-communist opposition, returned to their research. According to Karl A. Sinnhuber ("Central Europe: Mitteleuropa: Europe Centrale: An Analysis of a Geographical Term") most Central European states were unable to preserve their political independence and became Soviet satellites. Besides Austria, Switzerland and Yugoslavia, only the marginal European states of Cyprus, Finland, Malta and Sweden preserved their political sovereignty to a certain degree, being left out of any military alliances in Europe.
The opening of the Iron Curtain between Austria and Hungary at the Pan-European Picnic on 19 August 1989 then set in motion a peaceful chain reaction, at the end of which there was no longer an East Germany and the Eastern Bloc had disintegrated. It was the largest escape movement from East Germany since the Berlin Wall was built in 1961. After the picnic, which was based on an idea by Otto von Habsburg to test the reaction of the USSR and Mikhail Gorbachev to an opening of the border, tens of thousands of media-informed East Germans set off for Hungary. The leadership of the GDR in East Berlin did not dare to completely block the borders of their own country and the USSR did not respond at all. This broke the bracket of the Eastern Bloc and Central Europe subsequently became free from communism. Roles. According to American professor Ronald Tiersky, the 1991 summit held in Visegrád attended by the Czechoslovak, Hungarian and Polish presidents was hailed at the time as a major breakthrough in Central European cooperation, but the Visegrád Group became a vehicle for coordinating Central Europe's road to the European Union, while development of closer ties within the region languished.
American professor Peter J. Katzenstein described Central Europe as a way station in a Europeanization process that marks the transformation process of the Visegrád Group countries in different, though comparable ways. According to him, in Germany's contemporary public discourse "Central European identity" refers to the civilizational divide between Catholicism and Eastern Orthodoxy. He argued that there is no precise way to define Central Europe and that the region may even include Bulgaria, Estonia, Latvia and Serbia. Definitions. The issue of how to name and define the Central European area is subject to debates. Very often, the definition depends on the nationality and historical perspective of its author. The concept of "Central Europe" appeared in the 19th century. It was understood as a contact zone between the Southern and Northern areas, and later the Eastern and Western areas of Europe. Thinkers portrayed "Central Europe" either as a separate region, or a buffer zone between these regions. In the early nineteenth century, the terms "Middle" or "Central" Europe (known as "Mitteleuropa" in German and "Europe centrale" in French) were introduced in geographical scholarship in both German and French languages. At first, these terms were linked to the regions spanning from the Pyrenees to the Danube, which, according to German authors, could be united under German authority. However, after the Franco-Prussian war of 1870, the French began to exclude France from this area, and later the Germans also adopted this perspective by the end of World War I.
The concept of "Central" or "Middle Europe", understood as a region with German influence, lost a significant part of its popularity after WWI and was completely dismissed after WWII. Two defeats of Germany in the world wars, combined with the division of Germany, an almost complete disappearance of German-speaking communities in these countries, and the Communist-led isolation of Czechoslovakia, Hungary, Lithuania, Poland and Yugoslavia from the Western world, turned the concept of "Central/Middle Europe" into an anachronism. On the other side, the non-German areas of Central Europe were almost universally regarded as "Eastern European" primarily associated with the Soviet sphere of influence in the late 1940s–1980s. For the most part, this geographical framework lost its attraction after the end of the Cold War. A number of Post-Communist countries rather re-branded themselves in the 1990s as "Central European.", while avoiding the stained wording of "Middle Europe," which they associated with German influence in the region. This reinvented concept of "Central Europe" excluded Germany, Austria and Switzerland, reducing its coverage chiefly to Poland, the Czech Republic, Slovakia, Hungary, Lithuania and Yugoslavia.
Academic. The main proposed regional definitions, gathered by Polish historian Jerzy Kłoczowski and others, include: Former University of Vienna professor Lonnie R. Johnson points out criteria to distinguish Central Europe from Western, Northern, Eastern and Southern Europe: He also thinks that Central Europe is a dynamic historical concept, not a static spatial one. For example, a fair share of Belarus and Right-bank Ukraine are in Eastern Europe today, but years ago they were in the Polish–Lithuanian Commonwealth. Johnson's study on Central Europe received acclaim and positive reviews in the scientific community. However, according to Romanian researcher Maria Bucur, this very ambitious project suffers from the weaknesses imposed by its scope (almost 1600 years of history). Encyclopedias, gazetteers, dictionaries. The World Factbook defines Central Europe as: Austria, the Czech Republic, Germany, Hungary, Liechtenstein, Poland, Slovakia, Slovenia and Switzerland. "The Columbia Encyclopedia" includes: Austria, the Czech Republic, Germany, Hungary, Latvia, Lithuania, Poland, Slovakia and Switzerland. While it does not have a single article defining Central Europe, Encyclopædia Britannica includes the following countries in Central Europe in one or more of its articles: Austria, Bosnia and Herzegovina, Croatia, the Czech Republic, Germany, Hungary, Lithuania, Poland, Romania, Slovakia, Slovenia and Switzerland.
The French "Encyclopédie Larousse" defines Central Europe as a region comprising Austria, the Czech Republic, Germany, Liechtenstein, Slovakia, Slovenia and Switzerland. The German Encyclopaedia "Meyers Grosses Taschenlexikon" ("Meyers Big Pocket Encyclopedia"), 1999, defines Central Europe as the central part of Europe with no precise borders to the East and West. The term is mostly used to denominate the territory between the Schelde to Vistula and from the Danube to the Moravian Gate. The German (Standing Committee on Geographical Names), which develops and recommends rules for the uniform use of geographical names, proposes two sets of boundaries. The first follows international borders of current countries. The second subdivides and includes some countries based on cultural criteria. In comparison to some other definitions, it is broader, including Luxembourg, Estonia, Latvia, and in the second sense, the Kaliningrad Oblast and parts of Belarus, Ukraine, Romania, Serbia, Italy, and France. According to "Meyers Enzyklopädisches Lexikon", Central Europe is a part of Europe composed of Austria, Belgium, the Czech Republic, Slovakia, Germany, Hungary, Luxembourg, Netherlands, Poland, Romania and Switzerland, and northern marginal regions of Italy and Yugoslavia (northern states – Croatia and Slovenia), as well as northeastern France.
Geographical. There is no general agreement either on what geographic area constitutes Central Europe, nor on how to further subdivide it geographically. At times, the term "Central Europe" denotes a geographic definition as the Danube region in the heart of the continent, including the language and culture areas which are today included in the states of Austria, Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Hungary, Moldova, Poland, Romania, Serbia, Slovakia, Slovenia, Ukraine and usually also Germany. Governmental and standards organisations. The terminology EU11 countries refer the Central, Eastern and Baltic European member states which accessed in 2004 and after: in 2004 Czech Republic, Estonia, Latvia, Lithuania, Hungary, Poland, Slovenia, and Slovakia; in 2007 Bulgaria, Romania; and in 2013 Croatia. The EU-funded Interreg region "Central Europe" includes the following countries and regions: The Central European Free Trade Agreement includes the following countries: States. The choice of states that make up "Central Europe" is an ongoing source of controversy. Although views on which countries belong to Central Europe are vastly varied, according to many sources (see section Definitions) the region includes some or all of the states listed in the sections below:
Depending on the context, Central European countries are sometimes not seen as a specific group, but sorted as either Eastern or Western European countries. In this case Austria, Germany, Liechtenstein and Switzerland are often placed in Western Europe, while Croatia, the Czech Republic, Hungary, Lithuania, Poland, Slovakia and Slovenia are placed in Eastern Europe. Croatia is alternatively placed in Southeastern Europe. Additionally, Hungary and Slovenia are sometimes included in the region. Lithuania is alternatively placed in Northeastern Europe. Other countries and regions. Some sources also add regions of neighbouring countries for historical reasons, or based on geographical and/or cultural reasons: Geography. Geography defines Central Europe's natural borders with the neighbouring regions to the north across the Baltic Sea, namely Northern Europe (or Scandinavia), and to the south across the Alps, the Apennine peninsula (or Italy), and the Balkan peninsula across the Soča–Krka–Sava–Danube line. The borders to Western Europe and Eastern Europe are geographically less defined, and for this reason the cultural and historical boundaries migrate more easily west–east than south–north.
Southwards, the Pannonian Plain is bounded by the rivers Sava and Danube – and their respective floodplains. The Pannonian Plain stretches over the following countries: Austria, Croatia, Hungary, Romania, Serbia, Slovakia and Slovenia, and touches borders of Bosnia and Herzegovina and Ukraine ("peri- Pannonian states"). South of the Eastern Alps (spanning Austria, Germany, Italy, Liechtenstein, Slovenia and Switzerland), the Dinaric Alps extend for 650 kilometres along the coast of the Adriatic Sea (northwest-southeast), from the Julian Alps in the northwest down to the Šar-Korab massif, north–south. According to the Freie Universität Berlin, this mountain chain is classified as South Central European. The city of Trieste in this area, for example, expressly sees itself as a "città mitteleuropea". This is particularly because it lies at the interface between the Latin, Slavic, Germanic, Greek and Jewish culture on the one hand and the geographical area of the Mediterranean and the Alps on the other. A geographical and cultural assignment is made.
The Central European flora region stretches from Central France (the Massif Central) to the Northern Balkans, Central Romania (Carpathians) and Southern Scandinavia. Demography. Central Europe is one of the continent's most populous regions. It includes countries of varied sizes, ranging from tiny Liechtenstein to Germany, the second largest European country by population. Demographic figures for countries entirely located within notion of Central Europe ("the core countries") number around 173 million people, out of which around 82 million are residents of Germany. Other populations include: Poland with around 38.5 million residents, Czech Republic at 10.5 million, Hungary at 10 million, Austria with 9.2 million, Switzerland with 8.5 million, Slovakia at 5.4 million, Croatia with 4.3 million, Lithuania with 2.9 million, Slovenia with 2.1 million and Liechtenstein at a bit less than 40,000. If the countries which are sometimes also included in Central Europe were counted in, partially or in whole – Romania (20 million), Latvia (2 million), Estonia (1.3 million), Serbia (7.1 million) – this would contribute around an additional 30.4 million, although this figure would vary depending on whether a regional or integral approach is used. If smaller, western and eastern historical parts of Central Europe would be included in the demographic corpus, a further 20 million people of different nationalities would also be added in the overall count, surpassing a total of 200 million people.
Economy. Currencies. Currently, the members of the Eurozone include Austria, Croatia, Germany, Lithuania, Slovakia, and Slovenia. The Czech Republic, Hungary and Poland use their own currencies (koruna, forint, Polish złoty, respectively), but are obliged to adopt the Euro. Switzerland uses its own currency (Swiss franc), as does Serbia (dinar) and Romania (Romanian leu). Human Development Index. In 2018, Switzerland topped the HDI list among Central European countries, also ranking No. 2 in the world. Serbia rounded out the list at No. 11 (67 world). Globalisation. The index of globalization in Central European countries (2016 data): Switzerland topped this list as well (#1 world). Prosperity Index. Legatum Prosperity Index demonstrates an average and high level of prosperity in Central Europe (2018 data). Switzerland topped the index (#4 world). Corruption. Most countries in Central Europe tend to score above the average in the Corruption Perceptions Index (2018 data), led by Switzerland, Germany, and Austria.
Rail. Central Europe contains the continent's earliest railway systems, whose greatest expansion was recorded in Austrian, Czech, German, Hungarian and Swiss territories between 1860-1870s. By the mid-19th century Berlin, Vienna, Zurich, Pest and Prague were focal points for network lines connecting industrial areas of Saxony, Silesia, Bohemia, Moravia and Lower Austria with the Baltic (Kiel, Szczecin) and Adriatic (Rijeka, Trieste). By 1913, the combined length of the railway tracks of Austria and Hungary reached . By 1936, 70% of the Swiss Federal Railway network had undergone electrification. Rail infrastructure in Central Europe remains the densest in the world. Railway density as of 2022, with total length of lines operated (km) per 1,000 km2, from highest to lowest is Switzerland (129.2), the Czech Republic (120.7), Germany (108.8), Hungary (85.0), Slovakia (74.0), Austria (66.5), Poland (61.9), Slovenia (59.6), Serbia (49.2), Croatia (46.3) and Lithuania (29.4). River transport and canals. Before the first railroads appeared in the 1840s, river transport constituted the main means of communication and trade. Earliest canals included Plauen Canal (1745), Finow Canal, and also Bega Canal (1710) which connected Timișoara to Novi Sad and Belgrade via the Danube. The most significant achievement in this regard was the facilitation of navigability on the Danube from the Black sea to Ulm in the 19th century.
The economies of Austria, Croatia, the Czech Republic, Germany, Hungary, Lithuania, Poland, Slovakia, Slovenia and Switzerland tend to demonstrate high complexity. Industrialisation reached Central Europe relatively early beginning with Germany and the Czech lands near the end of the 18th century. The industrialization of the cities of Romania and Serbia started in the interwar period, and did not make significant progress until the post ww2 era. Agriculture. Central European countries are some of the most significant food producers in the world. Germany is the world's largest hops producer with 34.27% share in 2010, 3rd largest producer of rye and barley, 5th rapeseed producer, 6th largest milk producer, and 5th largest potato producer. Poland is the world's largest triticale producer, 2nd largest producer of raspberries, currants, 3rd largest of rye, the 5th apple and buckwheat producer, and 7th largest producer of potatoes. The Czech Republic is the world's 4th largest hops producer and 8th producer of triticale. Slovenia is one of the world's leading producers of honey and the world's 6th largest hops producer. Hungary is world's 5th hops and 7th largest triticale producer. Serbia is the world's 2nd largest producer of plums and 2nd largest producer of raspberries.