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Friday, July 28, 2023

Education

From Wikipedia, the free encyclopedia

photo of a lecture at the Faculty of Biomedical Engineering, Czech Technical University
photo of school children sitting in the shade of an orchard in Bamozai, near Gardez, Paktia Province, Afghanistan
photo of the FIRST Robotics Competition in Washington, D.C
photo of early childhood education in Ziway, Ethiopia
From top to bottom: Lecture at the Faculty of Biomedical Engineering, Czech Technical University, in Prague, Czech Republic; School children sitting in the shade of an orchard in Bamozai, near Gardez, Paktia Province, Afghanistan; Student participants in the FIRST Robotics Competition, Washington, D.C.; Early childhood education through USAID in Ziway, Ethiopia

Education is the transmission of knowledge, skills, and character traits. There are many debates about its precise definition, for example, about which aims it tries to achieve. A further issue is whether part of the meaning of education is that the change in the student is an improvement. Some researchers stress the role of critical thinking to distinguish education from indoctrination. These disagreements affect how to identify, measure, and improve forms of education. The term can also refer to the mental states and qualities of educated people. Additionally, it can mean the academic field studying education.

There are many types of education. Formal education happens in a complex institutional framework, like public schools. Non-formal education is also structured but happens outside the formal schooling system. Informal education is unstructured learning through daily experiences. Formal and non-formal education are divided into levels. They include early childhood education, primary education, secondary education, and tertiary education. Other classifications focus on the teaching method, like teacher-centered and student-centered education. Forms of education can also be distinguished by subject, like science education, language education, and physical education.

Education socializes children into society by teaching cultural values and norms. It equips them with the skills needed to become productive members of society. This way, it stimulates economic growth and raises awareness of local and global problems. Organized institutions affect many aspects of education. For example, governments set education policies. They determine when school classes happen, what is taught, and who can or must attend. International organizations, like UNESCO, have been influential in promoting primary education for all children.

Many factors influence whether education is successful. Psychological factors include motivation, intelligence, and personality. Social factors, like socioeconomic status, ethnicity, and gender, are often linked to discrimination. Further factors include educational technology, teacher quality, and parent involvement.

The main field investigating education is called education studies. It examines what education is and what aims it has. It also studies how it happens, what effects it has, and how to improve it. It has many subfields, like philosophy of education, psychology of education, sociology of education, economics of education, and comparative education. It also discusses the history of education. In prehistory, education happened informally through oral communication and imitation. With the rise of ancient civilizations, writing was invented, and the amount of knowledge grew. This caused a shift from informal to formal education. Initially, formal education was mainly available to elites and religious groups. The invention of the printing press in the 15th century made books more widely available. This increased general literacy. Beginning in the 18th and 19th centuries, public education became more important. It led to the worldwide process of making primary education available to all, free of charge, and compulsory up to a certain age.

Definitions

The definition of education has been explored by theorists from various fields. Many agree that education is a purposeful activity aimed at achieving certain goals, which include the transmission of knowledge, skills, and character traits. However, there is extensive debate regarding its exact nature beyond these general features. Some theorists view education primarily as a process that occurs during educational events such as schooling, teaching, and learning. Others perceive it not as a process but as the product resulting from this process, emphasizing the mental states and dispositions of educated persons. Additionally, the term may also refer to an academic field that studies the methods, processes, and social institutions involved in teaching and learning. The term "education" is derived from the Latin words educare, meaning "bring up, rear, educate", primarily related to the mind, and educere, meaning "bring out, lead forth", and refers to the bodily level.

Some theorists provide precise definitions by identifying the specific features that are exclusive to all forms of education. R. S. Peters, for instance, outlines three essential features for education:

  • It is concerned with the transmission of knowledge and understanding.
  • This transmission is worthwhile.
  • It is done in a morally appropriate manner in tune with the student's interests.

Such precise definitions often succeed at characterizing the most typical forms of education. But they are criticized because there are counterexamples. These difficulties have led some theorists to develop less precise concepts. Some of them are based on family resemblance. This means that all the forms of education are similar to each other. But they need not share a set of essential features that all of them have in common. Some theorists claim that the term "education" is context-dependent. This implies that its meaning varies depending on the situation in which it is used. Having a clear idea of what the term means is important to correctly identify forms of education. It also matters when trying to measure or improve them.

There is disagreement in the academic literature on whether education is an evaluative concept. This means that being good in some sense is part of the definition of education. So-called thick definitions affirm this. They may claim, for example, that an improvement of the learner is a requirement of education. Different thick definitions may still disagree among themselves on what kind of improvement is needed. Thin definitions, on the other hand, try to give a value-neutral account of education. A closely related distinction is that between descriptive and prescriptive conceptions. Descriptive conceptions aim to describe how the term is actually used by regular speakers. Prescriptive conceptions try to express what good education is or how it should be done.

Many thick and prescriptive conceptions rely on the aims of education to explain their view. This means that they see education as an activity that tries to achieve certain aims. These aims can be classified into different categories. There is one category for epistemic goods, like knowledge and understanding. Another category covers skills, like rationality and critical thinking. Additionally, there are character traits, like kindness and honesty.

Some theorists focus on a single overarching purpose of education and see the more specific aims as means to this end. For example, they may claim that socialization is the aim of education. This means that education is seen as the process of transmitting accumulated knowledge from one generation to the next. This process helps the student to function in society as a regular citizen. More person-centered definitions focus on the well-being of the student instead. For them, education is a process that helps them lead a good life or the life they wish to lead. Various scholars stress critical thinking to distinguish education from indoctrination. For them, mere indoctrination is only interested in instilling beliefs in the student, independent of whether they are rational. Education, on the other hand, should also foster the rational ability to critically reflect on those beliefs and question them. But some theorists contend that some forms of indoctrination may be necessary in the early stages of education. It may be needed until the child's mind is sufficiently developed.

Education can be characterized from the teacher's or the student's perspective. Teacher-centered definitions focus on the perspective and role of the teacher. They may claim, for example, that education is the transmission of knowledge and skills in a morally appropriate way. Student-centered definitions, on the other hand, see education from the student's experience in the learning process. For example, they may define it as a process that transforms and enriches their subsequent experience. Definitions taking both perspectives into account are also possible. This can take the form of describing the process as the shared experience of a common world. This shared experience involves discovery as well as posing and solving problems.

Types

There are many classifications of education. It depends on the institutional framework whether education is formal, non-formal, or informal. Levels of education are distinguished based on factors like the student's age and the complexity of the content. Some classifications focus on the learner or the topic. Others rely on the teaching method, the medium used, or the funding.

Formal, non-formal, and informal

Photo of a tutoring lesson
Photo of father and daughter cooking
Tutoring is an example of non-formal education while learning how to cook from ones parents belongs to informal education.

Education is often divided into types. The most common division is between formal, non-formal, and informal education. However, some theorists only distinguish between formal and informal education. Formal education happens in a complex institutional framework. Such frameworks have a chronological and hierarchical order. For instance, the modern schooling system has classes based on the student's age and progress, all the way from primary school to university. Formal education is usually controlled and guided by the government. It is normally compulsory up to a certain age.

Non-formal and informal education take place outside the formal schooling system. Non-formal education is a middle ground. Like formal education, it is organized, systematic, and carried out with a clear purpose in mind. Examples are tutoring, fitness classes, and the scouting movement. Informal education, on the other hand, happens in an unsystematic way through daily experiences and exposure to the environment. Unlike formal and non-formal education, there is usually no designated authority figure responsible for teaching. Informal education is present in many settings. It happens throughout one's life, mostly in a spontaneous way. This is how children learn their mother tongue from their parents or how people learn to prepare a dish by cooking together.

Some theorists distinguish the three types based on the location of learning. Formal education takes place in school. Informal education occurs in places of everyday routines. Non-formal education happens in places that are occasionally visited. There are also differences in the source of motivation. Formal education is mainly driven by extrinsic motivation for external rewards. Non-formal and informal education are closely linked to intrinsic motivation because the learning itself is enjoyed. The distinction between the three types is normally clear for the typical cases. But some forms of education do not easily fall into one category.

Formal education plays a central role in modern civilization. But in primitive cultures, most of the education happened on the informal level. This usually means that there is no distinction between activities focused on education and other activities. Instead, the whole environment acts as a form of school and most adults act as teachers. However, informal education is often not efficient enough to pass on large quantities of knowledge. To do so, a formal setting and well-trained teachers are usually required. This was one of the reasons why in the course of history, formal education became more and more important. In this process, the experience of education became more abstract and removed from daily life. More emphasis was put on grasping general patterns instead of observing and imitating behavior.

Levels

Types of education are often divided into levels or stages. The most influential framework is the International Standard Classification of Education. It is maintained by the United Nations Educational, Scientific and Cultural Organization (UNESCO). It covers both formal and non-formal education. It distinguishes levels based on the student's age, the duration of learning, and the complexity of the discussed content. Further criteria include entry requirements, teacher qualifications, and the intended outcome of successful completion. The levels are grouped together into early childhood education (level 0), primary education (level 1), secondary education (levels 2-3), post-secondary non-tertiary education (level 4), and tertiary education (levels 5-8).

photo of a kindergarten lesson in Japan
Young children in a kindergarten in Japan

Early childhood education is also known as preschool education or nursery education. It is the stage of education that begins with birth and lasts until the start of primary school. It follows the holistic aim of fostering early child development at the physical, mental, and social levels. It plays a key role in socialization and personality development. It includes various basic skills in the areas of communication, learning, and problem-solving. This way, it prepares children for their entry into primary education.

Primary (or elementary) education usually starts at the age of five to seven and lasts for four to seven years. It does not have any further entry requirements. Its main goal is to teach the basic skills in the fields of reading, writing, and mathematics. But it also covers the core knowledge in other fields, like history, geography, the sciences, music, and art. A further aim is to foster personal development. Today, primary education is compulsory in almost all countries. Over 90% of all primary-school-age children worldwide attend primary school.

Secondary education is the stage of education following primary education. It usually covers the ages of 12 to 18 years. It is commonly divided into lower secondary education (middle school or junior high school) and upper secondary education (high school, senior high school, or college depending on the country). Lower secondary education normally has the completion of primary school as its entry requirement. It aims to extend and deepen the learning outcomes. It is more strongly focused on subject-specific curricula and teachers are specialized in only one or a few specific subjects. One of its aims is to familiarize students with the basic theoretical concepts in these fields. This helps create a solid basis for lifelong learning. In some cases, it also includes vocational training. In many countries, it is the last stage of compulsory education.

A high-school senior (twelfth grade) classroom in Calhan, Colorado, United States

Upper secondary education aims to provide students with the skills and knowledge needed for employment or tertiary education. Its requirement is usually the completion of lower secondary education. Its subjects are more varied and complex. The students can often choose between a few subjects. Its successful completion is commonly tied to a formal qualification in the form of a high school diploma. There are some types of education after secondary education that do not belong to tertiary education. They are often similar in complexity to secondary education. But they tend to focus more on vocational training to prepare students for the job market.

photo of students in a laboratory at the Saint Petersburg State Polytechnical University
Students in a laboratory, Saint Petersburg State Polytechnical University

Tertiary education is also referred to as higher education. It expands upon the foundations of secondary education but has a more narrow and in-depth focus on a specific field or subject. Its completion leads to an academic degree. It can be divided into four levels: short-cycle tertiary, Bachelor's, Master's, and doctoral level education. They often form a hierarchical structure with later levels depending on the completion of previous levels.

Short-cycle tertiary education focuses on practical matters. It includes advanced vocational and professional training to prepare students for the job market in specialized professions. Bachelor's level education is also referred to as undergraduate education. It tends to be longer than short-cycle tertiary education. It is usually offered by universities and results in an intermediary academic certification in the form of a Bachelor's degree. Master's level education is more specialized than undergraduate education. Many programs require independent research in the form of a Master's thesis as a requirement for successful completion. Doctoral level education leads to an advanced research qualification, normally in the form of a doctor's degree. It usually requires the submission of a substantial academic work, such as a dissertation.

Others

Many other types of education are discussed in the academic literature, like the distinction between traditional and alternative education. Traditional education concerns long-established and mainstream schooling practices. It uses teacher-centered education and takes place in a well-regulated school environment. Regulations cover many aspects of education, such as the curriculum and the timeframe when classes start and end.

Image of a homeschooling lesson
Homeschooling is one form of alternative education.

Alternative education is an umbrella term for forms of schooling that differ from the mainstream traditional approach. For example, they may use a different learning environment, teach different subjects, or promote a different teacher-student relationship. Alternative schooling is characterized by voluntary participation, relatively small class and school sizes, and personalized instruction. This often results in a more welcoming and emotionally safe atmosphere. It encompasses many types like charter schools and special programs for problematic or gifted children. It also includes homeschooling and unschooling. For instance, Montessori schools, Waldorf schools, and Round Square schools are alternative schools. Further examples are Escuela Nueva schools, free schools, and democratic schools. Alternative education also includes indigenous education. It focuses on the transmission of knowledge and skills from an indigenous heritage. Its method gives more emphasis to narration and storytelling.

Other distinctions are based on who receives education. Categories by the age of the learner are childhood education, adolescent education, adult education, and elderly education. Special education is education that is specifically adapted to meet the unique needs of students with disabilities. It covers various forms of impairments on the intellectual, social, communicative, and physical levels. It aims to overcome the challenges posed by these impairments. This way, it provides the affected students with access to an appropriate education. When understood in the broadest sense, it also includes education for very gifted children who need adjusted curricula to reach their fullest potential.

Some classifications focus on the teaching method. In teacher-centered education, for example, the teacher takes center stage in providing students with information. It contrasts with student-centered education, in which students take on a more active and responsible role in shaping classroom activities. For conscious education, learning and teaching happen with a clear purpose in mind. Unconscious education, on the other hand, occurs on its own without being consciously planned or guided. This may happen in part through the personality of teachers and adults. Their personality can have indirect effects on the development of the student's personality.

Autodidacticism or self-education is self-directed learning. It happens without the guidance of teachers and institutions. It mainly occurs in adult education. It is characterized by the freedom to choose what and when to study. For this reason, it can be a more fulfilling learning experience. However, the lack of structure and guidance can result in aimless learning. Due to the absence of external feedback, autodidacts may develop false ideas and inaccurately assess their learning progress. It is closely related to lifelong education, which is an ongoing learning process throughout a person's entire life.

Forms of education can also be categorized by the subject and the medium used. Types based on the subject include science education, language education, art education, religious education, and physical education. Special mediums, such as radio or websites, are usually used in distance education. Examples include e-learning (use of computers), m-learning (use of mobile devices), and online education. They often take the form of open education, in which the courses and materials are made available with a minimal amount of barriers. They contrast with regular classroom or onsite education.

A further distinction is based on the type of funding. Public education is also referred to as state education. It is education funded and controlled by the government. It is available to the general public. It normally does not require tuition fees and is thus a form of free education. It contrasts with private education, which is funded and managed by private institutions. Private schools often have a more selective admission process. Many offer paid education by charging tuition fees. A more detailed classification focuses on the social institution responsible for education. It includes categories for institutions like family, school, civil society, state, and church.

Compulsory education is education that people are legally required to receive. It concerns mainly children who need to visit school up to a certain age. It contrasts with voluntary education, which people pursue by personal choice without a legal requirement.

Evidence-based education uses well-designed scientific studies to determine which methods of education work best. Its goal is to maximize the effectiveness of educational practices and policies. This is achieved by ensuring that they are informed by the best available empirical evidence. It includes evidence-based teaching, evidence-based learning, and school effectiveness research.

Role in society

Education plays various roles in society, including in social, economic, and personal fields. On a social level, education makes it possible to establish and sustain a stable society. It helps people acquire the basic skills needed to interact with their environment and fulfill their needs and desires. In modern society, this involves a wide range of skills like being able to speak, read, and write as well as to solve problems and to perform basic arithmetic tasks. It also includes the ability to handle information and communications technology. Children are socialized into society by acquiring these skills. Another key part of socialization is to learn how to live in social groups and interact with others by coming to understand social and cultural norms and expectations. This requires an understanding of what kinds of behavior are considered appropriate in different contexts. This way, new members are introduced to the culture, norms, and values that are dominant in their society. Socialization happens throughout life but is of special relevance to early childhood education. It enables a form of social cohesion, stability, and peace needed for people to productively engage in their daily business. Education plays a key role in democracies by increasing civic participation in the form of voting and organizing and through its tendency to promote equal opportunity for all.

A further issue is to enable people to become productive members of society by learning how to contribute to it. Through education, individuals acquire the technical and analytical skills needed to pursue their profession, produce goods, and provide services to others. In early societies, there was little specialization and each child would generally learn most of the tasks relevant to help their group. Modern societies are increasingly complex and many professions are only mastered by relatively few people who receive specialized training in addition to general education. Some of the skills and tendencies learned to function in society may conflict with each other and their value depends on the context of their usage. For example, fostering a questioning mind is necessary to develop the ability of critical thinking but in some cases, obedience to an authority is required to ensure social stability.

By helping people become productive members of society, education can stimulate economic growth and reduce poverty. It helps workers become more skilled and thereby increases the quality of the produced goods and services, which in turn leads to prosperity and increased competitiveness. In this regard, public education is often understood as a long-term investment to benefit society as a whole. The rate of return is especially high for investments in primary education. Besides increasing economic prosperity, it can also lead to technological and scientific advances as well as decrease unemployment while promoting social equity.

Education can prepare a country to adapt to changes and successfully face new challenges. For example, it can help raise awareness and contribute to the solution of contemporary global problems. Examples are climate change and sustainability as well as the widening inequalities between the rich and the poor. By making students aware of how their lives and actions affect others, it may inspire some to work toward realizing a more sustainable and fair world. This way, education serves not just the purpose of reproducing society as it is but can also be an instrument of development by realizing social transformation to improve society. This applies also to changing circumstances in the economic sector. For example, due to technological advances and increased automation, many jobs may be lost in the coming decades. This may render currently taught skills and knowledge redundant while shifting the importance to other areas. Education can be used to prepare people for such changes by adjusting the curriculum. This way, subjects involving digital literacy and skills in handling new technologies can be promoted. Another example is online education in the form of massive open online courses.

On a more individual level, education promotes personal development. This can include factors such as learning new skills, developing talents, fostering creativity, and increasing self-knowledge as well as improving problem-solving and decision-making abilities. It further has positive effects on health and well-being. While education is of high relevance in childhood, it does not end with adulthood and continues throughout life. This phenomenon is known as lifelong learning. It is of specific significance in contemporary society due to the rapid changes on many levels and the need for people to adjust to them.

The social importance of education is recognized in the annual International Day of Education on January 24. The year 1970 was declared International Education Year.

Role of institutions

photo of a sign of the Beijing Normal University
Beijing Normal University, which is governed directly by the Chinese Ministry of Education, is an example of collaboration between different entities in the education sector.

Organized institutions play a key role for various aspects of education. Institutions like schools, universities, teacher training institutions, and ministries of education make up the education sector. They interact both with each other and with other stakeholders, such as parents, local communities, and religious groups. Further stakeholders are NGOs, professionals in healthcare, law enforcement, media platforms, and political leaders. Many people are directly involved in the education sector. They include students, teachers, and school principals as well as school nurses and curriculum developers.

Many aspects of formal education are regulated by the policies of governmental institutions. They determine at what age children need to attend school and at what times classes are held as well as issues pertaining to the school environment, like infrastructure. Regulations also cover the exact requirements for teachers and how they are trained. An important aspect of education policy concerns the curriculum used for teaching at schools, colleges, and universities. A curriculum is a planned sequence of instructions or a program of learning that intends to guide the experience of learners to achieve the aims of education. The topics are usually selected based on their importance and depend on the type of school. For example, the goals of public school curricula are usually to offer a comprehensive and well-rounded education while vocational trainings focus more on specific practical skills within a field. The curricula also cover various aspects besides the topic to be discussed, such as the teaching method, the objectives to be reached, and the standards for assessing progress. By determining the curricula, governmental institutions have a strong impact on what knowledge and skills are transmitted to the students.

International organizations also play a key role in education. For example, UNESCO is an intergovernmental organization that promotes education in many ways. One of its activities is to advocate education policies. One example is the treaty UNCRC. It states that education is a human right of all children and young people. Another is the Education for All initiative. It aimed to offer basic education to all children, adolescents, and adults by the year 2015. It was later replaced by the initiative Sustainable Development Goals as goal 4. Related policies include the Convention against Discrimination in Education and the Futures of Education initiative.

Some influential organizations are not intergovernmental but non-governmental. For example, the International Association of Universities promotes the exchange of colleges and universities around the world. The International Baccalaureate offers international diploma programs. Many institutions, like the Erasmus Programme, facilitate student exchanges between countries.

Factors of educational success

Many factors influence educational achievement. They include psychological factors, which concern the student as an individual, and sociological factors, which pertain to the student's social environment. Further factors include access to educational technology, teacher quality, and parent involvement. Many of these factors overlap and influence each other.

Psychological

On a psychological level, relevant factors include motivation, intelligence, and personality. Motivation is the internal force propelling people to engage in learning. Motivated students are more likely to interact with the content to be learned by participating in classroom activities like discussions, which often results in a deeper understanding of the subject. It can also help students overcome difficulties and setbacks. An important distinction is between intrinsic and extrinsic motivation. Intrinsically motivated students are driven by an interest in the subject and the learning experience itself. Extrinsically motivated students seek external rewards. They may strive for good grades and recognition by their peers. It is often claimed that intrinsic motivation is more beneficial by leading to increased creativity and engagement as well as long-term commitment. Educational psychologists try to discover how to increase motivation. This can be achieved by encouraging some competition among students. Another factor is to balance positive and negative feedback in the form of praise and criticism.

Intelligence is another important factor in how people respond to education. It is a mental quality linked to the ability to learn from experience, to understand, and to employ knowledge and skills to solve problems. Those who have higher scores in intelligence metrics tend to perform better at school and go on to higher levels of education. Intelligence is often primarily associated with the so-called IQ, a standardized numerical metric for assessing intelligence. However, it has been argued that there different types of intelligences pertaining to distinct areas. According to Howard Gardner, some affect the areas of mathematics, logic, and spatial cognition. Others concern language and music. There are also distinct types for interacting with other people and with oneself. These forms are largely independent of each other. This means that someone may excel at one type while scoring low on another.

A closely related factor concerns learning styles. A learning style is a preferred form of acquiring knowledge and skills. For example, students with an auditory learning style find it easy to follow spoken lectures and discussions while visual learners benefit if information is presented visually in diagrams and videos. For efficient learning, it is often beneficial to include a wide variety of learning modalities. The learner's personality may also affect educational achievement. For example, the features of conscientiousness and openness to experience from the Big Five personality traits are linked to academic success. Further mental factors include self-efficacy, self-esteem, and metacognitive abilities.

Sociological

Unlike psychological factors, sociological factors focus not on the mental attributes of learners but on their social status and environment. They include socioeconomic status, ethnicity, and cultural background as well as gender. They are of interest to researchers since they are associated with inequality and discrimination. For this reason, they play a key role in policy-making in attempts to mitigate their effects.

Socioeconomic status depends on income but includes other factors as well, such as financial security, social status, and social class as well as quality of life attributes. Low socioeconomic status affects educational success in various ways. It is linked to slower cognitive developments in language and memory and higher dropout rates. Poor families may not have enough money to invest in educational resources like stimulating toys, books, and computers. Additionally, they may be unable to afford tuition at prestigious schools and are more likely to attend schools in poorer areas. Such schools tend to offer lower standards of teaching, for example, because of teacher shortages or because they lack educational materials and facilities, like libraries. Poor parents may also be unable to afford private lessons if their children lack behind. Students from a low socioeconomic status often have less access to information on higher education and may face additional difficulties in securing and repaying student loans. Low socioeconomic status also has many indirect negative effects because it is linked to lower physical and mental health. Due to these factors, social inequalities on the level of the parents are often reproduced in the children.

Ethnic background is linked to cultural differences and language barriers, which make it more difficult for students to adapt to the school environment and follow classes. Additional factors are explicit and implicit biases and discrimination toward ethnic minorities. This may affect the students' self-esteem and motivation as well as their access to educational opportunities. For example, teachers may hold stereotypical views even if they are not overtly racist, which can lead them to grade comparable performances differently based on the child's ethnicity.

Historically, gender has been a central factor in education since the roles of males and females were defined differently in many societies. Education tended to strongly favor males, who were expected to provide for the family. Females, on the other hand, were expected to manage the household and rear children, which severely hampered the educational opportunities available to them. And while these inequalities have improved in most modern societies, there are still gender differences in education. Among other things, this concerns biases and stereotypes linked to the role of gender in education. An example is that subjects like science, technology, engineering, and mathematics are often presented as male fields. This discourages female students to follow them.

One aspect of many social factors is given by the expectations associated with stereotypes. On the one hand, they work on an external level based on how people react to a person belonging to a certain group. On the other hand, they also affect the internal level because the person internalizes them and acts accordingly. In this sense, the expectations may turn into self-fulfilling prophecies by causing the educational outcomes they anticipate. This can happen both for positive and for negative stereotypes.

Technology and others

Technology plays another significant role in educational success. Educational technology is commonly associated with the use of modern digital devices, like computers. But understood in the broadest sense, it involves a wide range of resources and tools for learning, including basic aids that do not involve the use of machines, like regular books and worksheets.

photo of a group of children being introduced to a laptop
The OLPC laptop being introduced to children in Haiti

Educational technology can benefit learning in various ways. In the form of media, it often takes the role of the primary supplier of information in the classroom. This means that the teacher can focus their time and energy on other tasks, like planning the lesson and guiding students as well as assessing educational performance. It can also make information easier to understand, for example, by presenting it using graphics and videos rather than through mere text. In this regard, interactive elements may be used to make the learning experience more engaging, for example, in the form of educational games. Technology can be employed to make educational materials accessible to many people, like when using online resources. It additionally facilitates collaboration between students and communication with teachers. Lack of educational technology is an issue specifically in various developing countries and many efforts are made to address it, like the One Laptop per Child initiative.

A closely related issue concerns the effects of school infrastructure. It includes various physical aspects of the school, like its location and size as well as the available school facilities and equipment. For example, a healthy and safe environment, well-maintained classrooms, and suitable classroom furniture as well as the availability of a library and a canteen tend to contribute to educational success. The quality of the teacher also has an important impact on educational success. For example, skilled teachers are able to motivate and inspire students and are able to adjust their instructions to the students' abilities and needs. Important in this regard are the teacher's own education and training as well as their past teaching experience. A meta-analysis by Engin Karadağ et al. concludes that, compared to other influences, factors related to the school and the teacher have the biggest impact on student achievement.

An additional factor to boost educational achievement is parent involvement. It can make children more motivated and invested if they are aware that their parents care about their educational efforts. This tends to lead to increased self-esteem, better attendance rates, and more constructive behavior at school. Parent involvement also includes communication with teachers and other school staff, for example, to make other parties aware of current issues and how they may be resolved. Further relevant factors sometimes discussed in the academic literature include historical, political, demographic, religious, and legal aspects.

Education studies

photo of the cover of the title page of John Locke's 1693 book "Some Thoughts Concerning Education"
John Locke's book Some Thoughts Concerning Education from 1693 is one of the foundational works of education studies.

The main discipline investigating education is called education studies, also referred to as education sciences. It tries to determine how people transmit and acquire knowledge by studying the methods and forms of education. It is interested in its aims, effects, and value as well as the cultural, societal, governmental, and historical contexts that shape education. Education theorists integrate insights from many other fields of inquiry, including philosophy, psychology, sociology, economics, history, politics, and international relations. Because of these influences, some theorists claim that education studies is not an independent academic discipline like physics or history since its method and subject are not as clearly defined. Education studies differs from regular training programs, such as teacher training, since its focus on academic analysis and critical reflection goes beyond the skills needed to be a good teacher. It is not restricted to the topic of formal education but examines all forms and aspects of education.

Various research methods are used to study educational phenomena. They can roughly be divided into quantitative, qualitative, and mixed-methods approaches. Quantitative research emulates the methods found in the natural sciences by using precise numerical measurements to gather data from many observations and employs statistical tools to analyze it. It aims to arrive at an objective and impersonal understanding. Qualitative research usually has a much smaller sample size and tries to get an in-depth insight into more subjective and personal factors, like how different actors experience the process of education. Mixed-methods research aims to combine data gathered from both approaches to arrive at a balanced and comprehensive understanding. Data can be gathered in various ways, like using direct observation or test scores as well as interviews and questionnaires. Research can be employed to study basic factors affecting all forms of education, examine specific applications, look for solutions to concrete problems, and evaluate the effectiveness of projects.

Subfields

Education studies encompasses various subfields like philosophy of education, pedagogy, psychology of education, sociology of education, economics of education, comparative education, and history of education. The philosophy of education is the branch of applied philosophy that examines many of the basic assumptions underlying the theory and practice of education. It studies education both as a process and as a discipline while trying to provide exact definitions of its nature and how it differs from other phenomena. It further studies the purpose of education and its types as well as how to conceptualize teachers, students, and their relation. It includes educational ethics, which examines various moral issues in relation to education, for example, what ethical principles underlie it and how teachers should apply them to specific cases. The philosophy of education has a long history and was already discussed in ancient Greek philosophy.

The term "pedagogy" is sometimes used as a synonym for education studies but when understood in a more restricted sense, it refers to the subfield interested in teaching methods. It studies how the aims of education, like the transmission of knowledge or fostering skills and character traits, can be realized. It is interested in the methods and practices used for teaching in regular schools and some researchers restrict it to this domain. But in a wider sense, it covers all types of education, including forms of teaching outside schools. In this general sense, it explores how teachers can bring about experiences in learners to advance their understanding of the studied topic and how the learning itself takes place.

The psychology of education studies how education happens on the mental level, specifically how new knowledge and skills are acquired as well as how personal growth takes place. It studies the factors responsible for successful education and how these factors may differ from person to person. Important factors include intelligence, motivation, and personality. A central topic in this field is the interplay between nature and nurture and how it affects educational success. Influential psychological theories of education are behaviorism, cognitivism, and constructivism. Closely related fields are the neurology of education and educational neuroscience, which are interested in the neuropsychological processes and changes brought about through learning.

The sociology of education is concerned with how social factors influence education and how it leads to socialization. Social factors differ from mental factors studied by psychology and include aspects like socioeconomic status, ethnicity, and gender. The sociology of education studies how these factors, together with the dominant ideology in society, affect what kind of education is available to a person and how successful they are. Closely related questions include how education affects different groups in society and how educational experiences can form someone's personal identity. The sociology of education is interested in aspects that result in inequalities and is relevant to education policy, for example, when trying to identify what causes inequality and how to reduce it. Two influential schools of thought are consensus theory and conflict theory. Consensus theorists hold that education benefits society as a whole by preparing people for their roles. Conflict theories have a more negative outlook on the resulting inequalities and see education as a force used by the ruling class to promote their own agenda.

The economics of education is the field of inquiry studying how education is produced, distributed, and consumed. It tries to determine how resources should be used to improve education. An example is the question to what extent the quality of teachers is increased by raising their salary. Other questions are how smaller class sizes affect educational success and how to invest in new educational technologies. In this regard, it helps policy-makers decide how to distribute the limited resources most efficiently to benefit society as a whole. It also tries to understand what long-term role education plays for the economy of a country by providing a highly skilled labor force and increasing its competitiveness. A closely related issue concerns the economic advantages and disadvantages of different systems of education.

world map comparing different countries by their education index
Comparative education makes use of tools like education indices to compare systems of education in different countries.

Comparative education is the discipline that examines and contrasts systems of education. Comparisons can happen from a general perspective or focus on specific factors, like social, political, or economic aspects. It is often applied to different countries to assess the similarities and differences of their educational institutions and practices as well as to evaluate the consequences of the distinct approaches. It can be used to learn from other countries which education policies work and how one's own system of education may be improved. This practice is known as policy borrowing. It comes with many difficulties since the success of policies can depend to a large degree on the social and cultural context of students and teachers. A closely related and controversial topic concerns the question of whether the educational systems of developed countries are superior and should be exported to less developed countries. Other key topics are the internationalization of education and the role of education in transmitting from an authoritarian regime to a democracy.

The history of education examines the evolution of educational practices, systems, and institutions. It discusses various key processes, their possible causes and effects, and their relations to each other.

Aims and ideologies

A central topic in education studies concerns questions like why people should be educated and what goals should guide this process. Many aims of education have been suggested. On a basic level, education is about the acquisition of knowledge and skills but may also include personal development and fostering of character traits. Common suggestions encompass features like curiosity, creativity, rationality, and critical thinking as well as the tendency to think, feel, and act morally. Some scholars focus on liberal values linked to freedom, autonomy, and open-mindedness. But others prioritize qualities like obedience to authority, ideological purity, piety, and religious faith. An important discussion in this regard is about the role of critical thinking. It asks to what extent indoctrination forms part of education. On a social level, it is often stressed that education should socialize people. This way, it turns them into productive members of society while promoting good citizenship and preserving cultural values. A controversial issue in this regard concerns who primarily benefits from education: the educated person, society as a whole, or dominant groups within society.

Educational ideologies are systems of basic philosophical assumptions and principles. They cover various additional issues besides the aims of education, like what topics are learned and how the learning activity is structured. Other topics include the role of the teacher and how the results are to be assessed. They also include claims on how to structure the institutional framework and policies. There are many ideologies and they often overlap in various ways. For example, teacher-centered ideologies place the main emphasis on the teacher's role in transmitting knowledge to students. Student-centered ideologies give a more active role to the students in the process. Product-based ideologies discuss education from the perspective of the result to be achieved. They contrast with process-based ideologies, which focus on the processes of teaching and learning themselves. Another classification contrasts progressivism with more traditional and conservative ideologies. Further categories are humanism, romanticism, essentialism, encyclopaedism, and pragmatism. There are also distinct types for authoritarian and democratic ideologies.

Learning theories and teaching

Learning theories try to explain how learning happens. Influential theories are behaviorism, cognitivism, and constructivism. Behaviorism understands learning as a change in behavior in response to environmental stimuli. This happens by presenting the learner with a stimulus, associating this stimulus with the desired response, and solidifying this stimulus-response pair. Cognitivism sees learning as a change in cognitive structures and focuses on the mental processes involved in storing, retrieving, and processing information. According to constructivism, learning is based on the personal experience of each individual. It puts more emphasis on social interactions and how they are interpreted by the learner. These theories have important implications for how to teach. For example, behaviorists tend to focus on drills while cognitivists may advocate the use of mnemonics and constructivists tend to employ collaborative learning strategies.

An influential developmental theory of learning is due to Jean Piaget. He outlines four stages of learning through which children pass on their way to adulthood. They are the sensorimotor, the pre-operational, the concrete operational, and the formal operational stage. They correspond to different levels of abstraction. Early stages focus more on simple sensory and motor activities. Later stages include more complex internal representations and information processing in the form of logical reasoning. Various theories suggest that learning is more efficient when it is based on personal experience. An additional factor is to aim at a deeper understanding by connecting new to pre-existing knowledge rather than merely memorizing a list of unrelated facts.

The teaching method concerns the way the content is presented by the teacher, for example, whether group work is used instead of a focus on individual learning. There are many teaching methods available. Which one is most efficient in a case depends on various factors, like the subject matter as well as the learner's age and competence level. This is reflected in the fact that modern school systems organize students by age, competence, specialization, and native language into different classes to ensure a productive learning process. Different subjects frequently use very different approaches. For example, language education often focuses on verbal learning. Mathematical education, on the other hand, is about abstract and symbolic thinking together with deductive reasoning. One central requirement for teaching methodologies is to ensure that the learner remains motivated, for example, because of interest and curiosity or through external rewards.

Further aspects of teaching methods include the instructional media used, such as books, worksheets, and audio-visual recordings, and having some form of test or assessment to evaluate the learning progress. An important pedagogical aspect in many forms of modern education is that each lesson is part of a larger educational enterprise governed by a syllabus. It often covers several months or years. According to Herbartianism, teaching is divided into phases. The initial phase consists of preparing the student's mind for new information. Next, new ideas are first presented to the learner and then associated with ideas with which the learner is already familiar. In later phases, the understanding shifts to a more general level behind the specific instances and the ideas are then put into concrete practice.

History

The history of education studies the processes, methods, and institutions involved in teaching and learning. It tries to explain how they have interacted with each other and shaped educational practice until the present day. Education began in prehistory, as adults trained the young in the knowledge and skills deemed necessary in their society. For the most part, there were no specialized teachers and most adults taught the youth, usually informally during everyday activities. Education was achieved through oral communication and imitation. It could take the form of storytelling and singing to pass knowledge, values, and skills from one generation to the next.

The earliest ancient civilizations developed in the period from 3000 to 1500 BCE in Egypt, Mesopotamia, and North China. Ancient education was characterized by the invention of writing and the development of formal education. The invention of writing had a significant influence on the history of education as a whole. Through writing, it was possible to store and preserve information and make it accessible to more people. This enabled various subsequent developments, for example, the creation of educational tools, like textbooks, and institutions, like schools.

Mosaic from Pompeii depicting Plato's Academy
Plato's Academy is often seen as the first school of higher learning. (Mosaic from Pompeii).

Another key aspect of ancient education was the establishment of formal education. This became necessary since the amount of knowledge grew as civilizations evolved and informal education proved insufficient to transmit all knowledge from one generation to the next. Teachers would act as specialists to impart knowledge and education became more abstract and further removed from daily life. Formal education was still quite rare in ancient societies and was restricted to the intellectual elites. It happened in the form of training scribes and priests and covered various subjects besides reading and writing, including the humanities, science, medicine, mathematics, law, and astrology. Plato's Academy in Ancient Greece is often mentioned as one of the noteworthy achievements of ancient education. It is frequently described as the first institute of higher education. Another achievement is the creation of the Great Library of Alexandria in Ancient Egypt. Many see it as the most prestigious library of the ancient world.

In the medieval period, religious authorities had a lot of influence over formal education. This applied specifically to the role of the Catholic Church in Europe. But it is also seen in the Muslim world. Education there focused on the study of the Quran and its interpretations but also included knowledge of the sciences and the arts. Additionally, this period saw the establishment of universities as concentrated centers of higher education and research. The first universities were the University of Bologna, the University of Paris, and Oxford University. Another key development was the creation of guilds. Guilds were associations of skilled craftsmen and merchants who controlled the practice of their trades. They were responsible for vocational education and new members had to pass through different stages on their way to masterhood.

A woodcut from 1568 showing an old printing press
The invention of the printing press made written media widely available and led to a significant increase in general literacy.

The invention and popularization of the printing press in the middle of the 15th century by Johann Gutenberg had a profound impact on general education. It significantly reduced the cost of producing books, which were hand-written before, and thereby augmented the dissemination of written documents, including new forms like newspapers and pamphlets. The increased availability of written media had a significant influence on the general literacy of the population.

These changes prepared the rise of public education in the 18th and 19th centuries. This period saw the establishment of publicly funded schools with the aim of providing education for all. This contrasts with earlier periods, when formal education was primarily provided by private institutions, religious institutions, and individual tutors. Aztec civilization was an exception in this regard since formal education was mandatory for the youth regardless of social class as early as the 14th century. Closely related changes were to make education compulsory and free of charge for all children up to a certain age. Initiatives to promote public education and universal access to education made significant progress in the 20th and the 21st centuries and were promoted by intergovernmental organizations like the UN. Examples include the Universal Declaration of Human Rights, the Convention on the Rights of the Child, the Education for All initiative, the Millennium Development Goals, and the Sustainable Development Goals. These efforts resulted in a steady rise of all forms of education but affected primary education in particular. For example, in 1970, 28% of all primary-school-age children worldwide did not attend school while by 2015, this number dropped to 9%.

A side effect of the establishment of public education was the introduction of standardized curricula for public schools as well as standardized tests to assess the students' progress. It also affected teachers by setting in place institutions and norms to guide and oversee teacher training, for example, by establishing certification standards for teaching at public schools.

A further influence on contemporary education was the emergence of new educational technologies. For example, the widespread availability of computers and the internet dramatically increased access to educational resources and made new types of education possible, such as online education. This was of particular relevance during the COVID-19 pandemic. Schools all around the world had to close for extended periods. Many offered remote learning through video conferencing or pre-recorded video lessons to continue instruction. A further contemporary factor is the increased globalization and internationalization of education.

Action research

From Wikipedia, the free encyclopedia

Action research is a philosophy and methodology of research generally applied in the social sciences. It seeks transformative change through the simultaneous process of taking action and doing research, which are linked together by critical reflection. Kurt Lewin, then a professor a MIT, first coined the term "action research" in 1944. In his 1946 paper "Action Research and Minority Problems" he described action research as "a comparative research on the conditions and effects of various forms of social action and research leading to social action" that uses "a spiral of steps, each of which is composed of a circle of planning, action and fact-finding about the result of the action".

Process

Action research is an interactive inquiry process that balances problem-solving actions implemented in a collaborative context with data-driven collaborative analysis or research to understand underlying causes enabling future predictions about personal and organizational change.

After seven decades of action research development, many methods have evolved that adjust the balance to focus more on the actions taken or more on the research that results from the reflective understanding of the actions. This tension exists between:

  1. those who are more driven either by the researcher's agenda or by participants;
  2. those who are motivated primarily by instrumental goal attainment or by the aim of personal, organizational or societal transformation; and
  3. 1st-, to 2nd-, to 3rd-person research, that is, my research on my own action, aimed primarily at personal change; our research on our group (family/team), aimed primarily at improving the group; and 'scholarly' research aimed primarily at theoretical generalization or large-scale change.

Action research challenges traditional social science by moving beyond reflective knowledge created by outside experts sampling variables, to an active moment-to-moment theorizing, data collecting and inquiry occurring in the midst of emergent structure. "Knowledge is always gained through action and for action. From this starting point, to question the validity of social knowledge is to question, not how to develop a reflective science about action, but how to develop genuinely well-informed action – how to conduct an action science". In this sense, engaging in action research is a form of problem-based investigation by practitioners into their practice, thus it is an empirical process. The goal is both to create and share knowledge in the social sciences.

Major theoretical approaches

Chris Argyris' action science

Chris Argyris' action science begins with the study of how human beings design their actions in difficult situations. Humans design their actions to achieve intended consequences and are governed by a set of environment variables. How those governing variables are treated in designing actions are the key differences between single-loop and double-loop learning. When actions are designed to achieve the intended consequences and to suppress conflict about the governing variables, a single-loop learning cycle usually ensues.

On the other hand, when actions are taken not only to achieve the intended consequences, but also to openly inquire about conflict and to possibly transform the governing variables, both single- and double-loop learning cycles usually ensue. (Argyris applies single- and double-loop learning concepts not only to personal behaviors but also to organizational behaviors in his models.) This is different from experimental research in which environmental variables are controlled and researchers try to find out cause and effect in an isolated environment.

John Heron and Peter Reason's cooperative inquiry

Cooperative, aka collaborative, inquiry was first proposed by John Heron in 1971 and later expanded with Peter Reason and Demi Brown. The major idea is to "research 'with' rather than 'on' people." It emphasizes the full involvement in research decisions of all active participants as co-researchers.

Cooperative inquiry creates a research cycle among 4 different types of knowledge: propositional (as in contemporary science), practical (the knowledge that comes with actually doing what you propose), experiential (the real-time feedback we get about our interaction with the larger world) and presentational (the artistic rehearsal process through which we craft new practices). At every cycle, the research process includes these four stages, with deepening experience and knowledge of the initial proposition, or of new propositions.

Paulo Freire's participatory action research

Participatory action research builds on the critical pedagogy put forward by Paulo Freire as a response to the traditional formal models of education where the "teacher" stands at the front and "imparts" information to the "students" who are passive recipients. This was further developed in "adult education" models throughout Latin America.

Orlando Fals-Borda (1925–2008), Colombian sociologist and political activist, was one of the principal promoters of participatory action research (IAP in Spanish) in Latin America. He published a "double history of the coast", book that compares the official "history" and the non-official "story" of the north coast of Colombia.

William Barry's living educational theory approach to action research

William Barry defined an approach to action research which focuses on creating ontological weight. He adapted the idea of ontological weight to action research from existential Christian philosopher Gabriel Marcel. Barry was influenced by Jean McNiff's and Jack Whitehead's phraseology of living theory action research but was diametrically opposed to the validation process advocated by Whitehead which demanded video "evidence" of "energy flowing values" and his atheistic ontological position which influenced his conception of values in action research.

Barry explained that living educational theory (LET) is "a critical and transformational approach to action research. It confronts the researcher to challenge the status quo of their educational practice and to answer the question, 'How can I improve what I'm doing?' Researchers who use this approach must be willing to recognize and assume responsibility for being 'living contradictions' in their professional practice – thinking one way and acting in another. The mission of the LET action researcher is to overcome workplace norms and self-behavior which contradict the researcher's values and beliefs. The vision of the LET researcher is to make an original contribution to knowledge through generating an educational theory proven to improve the learning of people within a social learning space. The standard of judgment for theory validity is evidence of workplace reform, transformational growth of the researcher, and improved learning by the people researcher claimed to have influenced...".

Action research in organization development

Wendell L. French and Cecil Bell define organization development (OD) at one point as "organization improvement through action research". If one idea can be said to summarize OD's underlying philosophy, it would be action research as it was conceptualized by Kurt Lewin and later elaborated and expanded on by other behavioral scientists. Concerned with social change and, more particularly, with effective, permanent social change, Lewin believed that the motivation to change was strongly related to action: If people are active in decisions affecting them, they are more likely to adopt new ways. "Rational social management", he said, "proceeds in a spiral of steps, each of which is composed of a circle of planning, action and fact-finding about the result of action".[18]

  • Unfreezing: first step.
  • Changing: The situation is diagnosed and new models of behavior are explored and tested.
  • Refreezing: Application of new behavior is evaluated, and if reinforcing, adopted.
Figure 1: Systems model of action-research process

Lewin's description of the process of change involves three steps: Figure 1 summarizes the steps and processes involved in planned change through action research. Action research is depicted as a cyclical process of change.

  1. The cycle begins with a series of planning actions initiated by the client and the change agent working together. The principal elements of this stage include a preliminary diagnosis, data gathering, feedback of results, and joint action planning. In the language of systems theory, this is the input phase, in which the client system becomes aware of problems as yet unidentified, realizes it may need outside help to effect changes, and shares with the consultant the process of problem diagnosis.
  2. The second stage of action research is the action, or transformation, phase. This stage includes actions relating to learning processes (perhaps in the form of role analysis) and to planning and executing behavioral changes in the client organization. As shown in Figure 1, feedback at this stage would move via Feedback Loop A and would have the effect of altering previous planning to bring the learning activities of the client system into better alignment with change objectives. Included in this stage is action-planning activity carried out jointly by the consultant and members of the client system. Following the workshop or learning sessions, these action steps are carried out on the job as part of the transformation stage.
  3. The third stage of action research is the output or results phase. This stage includes actual changes in behavior (if any) resulting from corrective action steps taken following the second stage. Data are again gathered from the client system so that progress can be determined and necessary adjustments in learning activities can be made. Minor adjustments of this nature can be made in learning activities via Feedback Loop B (see Figure 1).

Major adjustments and reevaluations would return the OD project to the first or planning stage for basic changes in the program. The action-research model shown in Figure 1 closely follows Lewin's repetitive cycle of planning, action, and measuring results. It also illustrates other aspects of Lewin's general model of change. As indicated in the diagram, the planning stage is a period of unfreezing, or problem awareness. The action stage is a period of changing, that is, trying out new forms of behavior in an effort to understand and cope with the system's problems. (There is inevitable overlap between the stages, since the boundaries are not clear-cut and cannot be in a continuous process).

The results stage is a period of refreezing, in which new behaviors are tried out on the job and, if successful and reinforcing, become a part of the system's repertoire of problem-solving behavior. Action research is problem centered, client centered, and action oriented. It involves the client system in a diagnostic, active-learning, problem-finding and problem-solving process.

Worldwide expansion

Action research has become a significant methodology for intervention, development and change within groups and communities. It is promoted and implemented by many international development agencies and university programs, as well as local community organizations around the world, such as AERA and Claremont Lincoln in America, CARN in the United Kingdom, CCAR in Sweden, CLAYSS in Argentina, CARPED and PRIA in India, and ARNA in the Americas.

The Center for Collaborative Action Research makes available a set of twelve tutorials as a self-paced online course in learning how to do action research. It includes a free workbook that can be used online or printed.

Journal

The field is supported by a quarterly peer-reviewed academic journal, Action Research, founded in 2003 and edited by Hilary Bradbury.

Electric power system

From Wikipedia, the free encyclopedia
A steam turbine used to provide electric power

An electric power system is a network of electrical components deployed to supply, transfer, and use electric power. An example of a power system is the electrical grid that provides power to homes and industries within an extended area. The electrical grid can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centers to the load centers, and the distribution system that feeds the power to nearby homes and industries.

Smaller power systems are also found in industry, hospitals, commercial buildings, and homes. A single line diagram helps to represent this whole system. The majority of these systems rely upon three-phase AC power—the standard for large-scale power transmission and distribution across the modern world. Specialized power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners, submarines, and automobiles.

History

A sketch of the Pearl Street Station

In 1881, two electricians built the world's first power system at Godalming in England. It was powered by two water wheels and produced an alternating current that in turn supplied seven Siemens arc lamps at 250 volts and 34 incandescent lamps at 40 volts. However, supply to the lamps was intermittent and in 1882 Thomas Edison and his company, Edison Electric Light Company, developed the first steam-powered electric power station on Pearl Street in New York City. The Pearl Street Station initially powered around 3,000 lamps for 59 customers. The power station generated direct current and operated at a single voltage. Direct current power could not be transformed easily or efficiently to the higher voltages necessary to minimize power loss during long-distance transmission, so the maximum economic distance between the generators and load was limited to around half a mile (800 m).

That same year in London, Lucien Gaulard and John Dixon Gibbs demonstrated the "secondary generator"—the first transformer suitable for use in a real power system. The practical value of Gaulard and Gibbs' transformer was demonstrated in 1884 at Turin where the transformer was used to light up 40 kilometers (25 miles) of railway from a single alternating current generator. Despite the success of the system, the pair made some fundamental mistakes. Perhaps the most serious was connecting the primaries of the transformers in series so that active lamps would affect the brightness of other lamps further down the line.

In 1885, Ottó Titusz Bláthy working with Károly Zipernowsky and Miksa Déri perfected the secondary generator of Gaulard and Gibbs, providing it with a closed iron core and its present name: the "transformer". The three engineers went on to present a power system at the National General Exhibition of Budapest that implemented the parallel AC distribution system proposed by a British scientist in which several power transformers have their primary windings fed in parallel from a high-voltage distribution line. The system lit more than 1000 carbon filament lamps and operated successfully from May until November of that year.

Also in 1885 George Westinghouse, an American entrepreneur, obtained the patent rights to the Gaulard-Gibbs transformer and imported a number of them along with a Siemens generator, and set his engineers to experimenting with them in hopes of improving them for use in a commercial power system. In 1886, one of Westinghouse's engineers, William Stanley, independently recognized the problem with connecting transformers in series as opposed to parallel and also realized that making the iron core of a transformer a fully enclosed loop would improve the voltage regulation of the secondary winding. Using this knowledge he built a multi-voltage transformer-based alternating-current power system serving multiple homes and businesses at Great Barrington, Massachusetts in 1886. The system was unreliable and short-lived, though, due primarily to generation issues. However, based on that system, Westinghouse would begin installing AC transformer systems in competition with the Edison Company later that year. In 1888, Westinghouse licensed Nikola Tesla's patents for a polyphase AC induction motor and transformer designs. Tesla consulted for a year at the Westinghouse Electric & Manufacturing Company's but it took a further four years for Westinghouse engineers to develop a workable polyphase motor and transmission system.

By 1889, the electric power industry was flourishing, and power companies had built thousands of power systems (both direct and alternating current) in the United States and Europe. These networks were effectively dedicated to providing electric lighting. During this time the rivalry between Thomas Edison and George Westinghouse's companies had grown into a propaganda campaign over which form of transmission (direct or alternating current) was superior, a series of events known as the "war of the currents". In 1891, Westinghouse installed the first major power system that was designed to drive a 100 horsepower (75 kW) synchronous electric motor, not just provide electric lighting, at Telluride, Colorado. On the other side of the Atlantic, Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown, built the first long-distance (175 kilometers (109 miles)) high-voltage (15 kV, then a record) three-phase transmission line from Lauffen am Neckar to Frankfurt am Main for the Electrical Engineering Exhibition in Frankfurt, where power was used to light lamps and run a water pump. In the United States the AC/DC competition came to an end when Edison General Electric was taken over by their chief AC rival, the Thomson-Houston Electric Company, forming General Electric. In 1895, after a protracted decision-making process, alternating current was chosen as the transmission standard with Westinghouse building the Adams No. 1 generating station at Niagara Falls and General Electric building the three-phase alternating current power system to supply Buffalo at 11 kV.

Developments in power systems continued beyond the nineteenth century. In 1936 the first experimental high voltage direct current (HVDC) line using mercury arc valves was built between Schenectady and Mechanicville, New York. HVDC had previously been achieved by series-connected direct current generators and motors (the Thury system) although this suffered from serious reliability issues. The first solid-state metal diode suitable for general power uses was developed by Ernst Presser at TeKaDe in 1928. It consisted of a layer of selenium applied on an aluminum plate. In 1957, a General Electric research group developed the first thyristor suitable for use in power applications, starting a revolution in power electronics. In that same year, Siemens demonstrated a solid-state rectifier, but it was not until the early 1970s that solid-state devices became the standard in HVDC, when GE emerged as one of the top suppliers of thyristor-based HVDC. In 1979, a European consortium including Siemens, Brown Boveri & Cie and AEG realized the record HVDC link from Cabora Bassa to Johannesburg, extending more than 1,420 kilometers (880 miles) that carried 1.9 GW at 533 kV.

In recent times, many important developments have come from extending innovations in the information and communications technology (ICT) field to the power engineering field. For example, the development of computers meant load flow studies could be run more efficiently, allowing for much better planning of power systems. Advances in information technology and telecommunication also allowed for effective remote control of a power system's switchgear and generators.

Basics of electric power

Animation of three-phase alternating current

Electric power is the product of two quantities: current and voltage. These two quantities can vary with respect to time (AC power) or can be kept at constant levels (DC power).

Most refrigerators, air conditioners, pumps and industrial machinery use AC power, whereas most computers and digital equipment use DC power (digital devices plugged into the mains typically have an internal or external power adapter to convert from AC to DC power). AC power has the advantage of being easy to transform between voltages and is able to be generated and utilised by brushless machinery. DC power remains the only practical choice in digital systems and can be more economical to transmit over long distances at very high voltages (see HVDC).

The ability to easily transform the voltage of AC power is important for two reasons: firstly, power can be transmitted over long distances with less loss at higher voltages. So in power systems where generation is distant from the load, it is desirable to step-up (increase) the voltage of power at the generation point and then step-down (decrease) the voltage near the load. Secondly, it is often more economical to install turbines that produce higher voltages than would be used by most appliances, so the ability to easily transform voltages means this mismatch between voltages can be easily managed.

Solid-state devices, which are products of the semiconductor revolution, make it possible to transform DC power to different voltages, build brushless DC machines and convert between AC and DC power. Nevertheless, devices utilising solid-state technology are often more expensive than their traditional counterparts, so AC power remains in widespread use.

Components of power systems

Supplies

The majority of the world's power still comes from coal-fired power stations like this

All power systems have one or more sources of power. For some power systems, the source of power is external to the system but for others, it is part of the system itself—it is these internal power sources that are discussed in the remainder of this section. Direct current power can be supplied by batteries, fuel cells or photovoltaic cells. Alternating current power is typically supplied by a rotor that spins in a magnetic field in a device known as a turbo generator. There have been a wide range of techniques used to spin a turbine's rotor, from steam heated using fossil fuel (including coal, gas and oil) or nuclear energy to falling water (hydroelectric power) and wind (wind power).

The speed at which the rotor spins in combination with the number of generator poles determines the frequency of the alternating current produced by the generator. All generators on a single synchronous system, for example, the national grid, rotate at sub-multiples of the same speed and so generate electric current at the same frequency. If the load on the system increases, the generators will require more torque to spin at that speed and, in a steam power station, more steam must be supplied to the turbines driving them. Thus the steam used and the fuel expended directly relate to the quantity of electrical energy supplied. An exception exists for generators incorporating power electronics such as gearless wind turbines or linked to a grid through an asynchronous tie such as a HVDC link — these can operate at frequencies independent of the power system frequency.

Depending on how the poles are fed, alternating current generators can produce a variable number of phases of power. A higher number of phases leads to more efficient power system operation but also increases the infrastructure requirements of the system. Electricity grid systems connect multiple generators operating at the same frequency: the most common being three-phase at 50 or 60 Hz.

There are a range of design considerations for power supplies. These range from the obvious: How much power should the generator be able to supply? What is an acceptable length of time for starting the generator (some generators can take hours to start)? Is the availability of the power source acceptable (some renewables are only available when the sun is shining or the wind is blowing)? To the more technical: How should the generator start (some turbines act like a motor to bring themselves up to speed in which case they need an appropriate starting circuit)? What is the mechanical speed of operation for the turbine and consequently what are the number of poles required? What type of generator is suitable (synchronous or asynchronous) and what type of rotor (squirrel-cage rotor, wound rotor, salient pole rotor or cylindrical rotor)?

Loads

A toaster is a great example of a single-phase load that might appear in a residence. Toasters typically draw 2 to 10 amps at 110 to 260 volts consuming around 600 to 1200 watts of power.

Power systems deliver energy to loads that perform a function. These loads range from household appliances to industrial machinery. Most loads expect a certain voltage and, for alternating current devices, a certain frequency and number of phases. The appliances found in residential settings, for example, will typically be single-phase operating at 50 or 60 Hz with a voltage between 110 and 260 volts (depending on national standards). An exception exists for larger centralized air conditioning systems as these are now often three-phase because this allows them to operate more efficiently. All electrical appliances also have a wattage rating, which specifies the amount of power the device consumes. At any one time, the net amount of power consumed by the loads on a power system must equal the net amount of power produced by the supplies less the power lost in transmission.

Making sure that the voltage, frequency and amount of power supplied to the loads is in line with expectations is one of the great challenges of power system engineering. However it is not the only challenge, in addition to the power used by a load to do useful work (termed real power) many alternating current devices also use an additional amount of power because they cause the alternating voltage and alternating current to become slightly out-of-sync (termed reactive power). The reactive power like the real power must balance (that is the reactive power produced on a system must equal the reactive power consumed) and can be supplied from the generators, however it is often more economical to supply such power from capacitors (see "Capacitors and reactors" below for more details).

A final consideration with loads has to do with power quality. In addition to sustained overvoltages and undervoltages (voltage regulation issues) as well as sustained deviations from the system frequency (frequency regulation issues), power system loads can be adversely affected by a range of temporal issues. These include voltage sags, dips and swells, transient overvoltages, flicker, high-frequency noise, phase imbalance and poor power factor. Power quality issues occur when the power supply to a load deviates from the ideal. Power quality issues can be especially important when it comes to specialist industrial machinery or hospital equipment.

Conductors

Partially insulated medium-voltage conductors in California

Conductors carry power from the generators to the load. In a grid, conductors may be classified as belonging to the transmission system, which carries large amounts of power at high voltages (typically more than 69 kV) from the generating centres to the load centres, or the distribution system, which feeds smaller amounts of power at lower voltages (typically less than 69 kV) from the load centres to nearby homes and industry.

Choice of conductors is based on considerations such as cost, transmission losses and other desirable characteristics of the metal like tensile strength. Copper, with lower resistivity than aluminum, was once the conductor of choice for most power systems. However, aluminum has a lower cost for the same current carrying capacity and is now often the conductor of choice. Overhead line conductors may be reinforced with steel or aluminium alloys.

Conductors in exterior power systems may be placed overhead or underground. Overhead conductors are usually air insulated and supported on porcelain, glass or polymer insulators. Cables used for underground transmission or building wiring are insulated with cross-linked polyethylene or other flexible insulation. Conductors are often stranded for to make them more flexible and therefore easier to install.

Conductors are typically rated for the maximum current that they can carry at a given temperature rise over ambient conditions. As current flow increases through a conductor it heats up. For insulated conductors, the rating is determined by the insulation. For bare conductors, the rating is determined by the point at which the sag of the conductors would become unacceptable.

Capacitors and reactors

A synchronous condenser installation at Templestowe substation, Melbourne, Victoria

The majority of the load in a typical AC power system is inductive; the current lags behind the voltage. Since the voltage and current are out-of-phase, this leads to the emergence of an "imaginary" form of power known as reactive power. Reactive power does no measurable work but is transmitted back and forth between the reactive power source and load every cycle. This reactive power can be provided by the generators themselves but it is often cheaper to provide it through capacitors, hence capacitors are often placed near inductive loads (i.e. if not on-site at the nearest substation) to reduce current demand on the power system (i.e. increase the power factor).

Reactors consume reactive power and are used to regulate voltage on long transmission lines. In light load conditions, where the loading on transmission lines is well below the surge impedance loading, the efficiency of the power system may actually be improved by switching in reactors. Reactors installed in series in a power system also limit rushes of current flow, small reactors are therefore almost always installed in series with capacitors to limit the current rush associated with switching in a capacitor. Series reactors can also be used to limit fault currents.

Capacitors and reactors are switched by circuit breakers, which results in sizeable step changes of reactive power. A solution to this comes in the form of synchronous condensers, static VAR compensators and static synchronous compensators. Briefly, synchronous condensers are synchronous motors that spin freely to generate or absorb reactive power. Static VAR compensators work by switching in capacitors using thyristors as opposed to circuit breakers allowing capacitors to be switched-in and switched-out within a single cycle. This provides a far more refined response than circuit-breaker-switched capacitors. Static synchronous compensators take this a step further by achieving reactive power adjustments using only power electronics.

Power electronics

This external household AC to DC power adapter uses power electronics

Power electronics are semiconductor based devices that are able to switch quantities of power ranging from a few hundred watts to several hundred megawatts. Despite their relatively simple function, their speed of operation (typically in the order of nanoseconds) means they are capable of a wide range of tasks that would be difficult or impossible with conventional technology. The classic function of power electronics is rectification, or the conversion of AC-to-DC power, power electronics are therefore found in almost every digital device that is supplied from an AC source either as an adapter that plugs into the wall (see photo) or as component internal to the device. High-powered power electronics can also be used to convert AC power to DC power for long distance transmission in a system known as HVDC. HVDC is used because it proves to be more economical than similar high voltage AC systems for very long distances (hundreds to thousands of kilometres). HVDC is also desirable for interconnects because it allows frequency independence thus improving system stability. Power electronics are also essential for any power source that is required to produce an AC output but that by its nature produces a DC output. They are therefore used by photovoltaic installations.

Power electronics also feature in a wide range of more exotic uses. They are at the heart of all modern electric and hybrid vehicles—where they are used for both motor control and as part of the brushless DC motor. Power electronics are also found in practically all modern petrol-powered vehicles, this is because the power provided by the car's batteries alone is insufficient to provide ignition, air-conditioning, internal lighting, radio and dashboard displays for the life of the car. So the batteries must be recharged while driving—a feat that is typically accomplished using power electronics.

Some electric railway systems also use DC power and thus make use of power electronics to feed grid power to the locomotives and often for speed control of the locomotive's motor. In the middle twentieth century, rectifier locomotives were popular, these used power electronics to convert AC power from the railway network for use by a DC motor. Today most electric locomotives are supplied with AC power and run using AC motors, but still use power electronics to provide suitable motor control. The use of power electronics to assist with the motor control and with starter circuits, in addition to rectification, is responsible for power electronics appearing in a wide range of industrial machinery. Power electronics even appear in modern residential air conditioners allow are at the heart of the variable speed wind turbine.

Protective devices

A multifunction digital protective relay typically installed at a substation to protect a distribution feeder

Power systems contain protective devices to prevent injury or damage during failures. The quintessential protective device is the fuse. When the current through a fuse exceeds a certain threshold, the fuse element melts, producing an arc across the resulting gap that is then extinguished, interrupting the circuit. Given that fuses can be built as the weak point of a system, fuses are ideal for protecting circuitry from damage. Fuses however have two problems: First, after they have functioned, fuses must be replaced as they cannot be reset. This can prove inconvenient if the fuse is at a remote site or a spare fuse is not on hand. And second, fuses are typically inadequate as the sole safety device in most power systems as they allow current flows well in excess of that that would prove lethal to a human or animal.

The first problem is resolved by the use of circuit breakers—devices that can be reset after they have broken current flow. In modern systems that use less than about 10 kW, miniature circuit breakers are typically used. These devices combine the mechanism that initiates the trip (by sensing excess current) as well as the mechanism that breaks the current flow in a single unit. Some miniature circuit breakers operate solely on the basis of electromagnetism. In these miniature circuit breakers, the current is run through a solenoid, and, in the event of excess current flow, the magnetic pull of the solenoid is sufficient to force open the circuit breaker's contacts (often indirectly through a tripping mechanism).

In higher powered applications, the protective relays that detect a fault and initiate a trip are separate from the circuit breaker. Early relays worked based upon electromagnetic principles similar to those mentioned in the previous paragraph, modern relays are application-specific computers that determine whether to trip based upon readings from the power system. Different relays will initiate trips depending upon different protection schemes. For example, an overcurrent relay might initiate a trip if the current on any phase exceeds a certain threshold whereas a set of differential relays might initiate a trip if the sum of currents between them indicates there may be current leaking to earth. The circuit breakers in higher powered applications are different too. Air is typically no longer sufficient to quench the arc that forms when the contacts are forced open so a variety of techniques are used. One of the most popular techniques is to keep the chamber enclosing the contacts flooded with sulfur hexafluoride (SF6)—a non-toxic gas with sound arc-quenching properties. Other techniques are discussed in the reference.

The second problem, the inadequacy of fuses to act as the sole safety device in most power systems, is probably best resolved by the use of residual-current devices (RCDs). In any properly functioning electrical appliance, the current flowing into the appliance on the active line should equal the current flowing out of the appliance on the neutral line. A residual current device works by monitoring the active and neutral lines and tripping the active line if it notices a difference. Residual current devices require a separate neutral line for each phase and to be able to trip within a time frame before harm occurs. This is typically not a problem in most residential applications where standard wiring provides an active and neutral line for each appliance (that's why your power plugs always have at least two tongs) and the voltages are relatively low however these issues limit the effectiveness of RCDs in other applications such as industry. Even with the installation of an RCD, exposure to electricity can still prove fatal.

SCADA systems

In large electric power systems, supervisory control and data acquisition (SCADA) is used for tasks such as switching on generators, controlling generator output and switching in or out system elements for maintenance. The first supervisory control systems implemented consisted of a panel of lamps and switches at a central console near the controlled plant. The lamps provided feedback on the state of the plant (the data acquisition function) and the switches allowed adjustments to the plant to be made (the supervisory control function). Today, SCADA systems are much more sophisticated and, due to advances in communication systems, the consoles controlling the plant no longer need to be near the plant itself. Instead, it is now common for plants to be controlled with equipment similar (if not identical) to a desktop computer. The ability to control such plants through computers has increased the need for security—there have already been reports of cyber-attacks on such systems causing significant disruptions to power systems.

Power systems in practice

Despite their common components, power systems vary widely both with respect to their design and how they operate. This section introduces some common power system types and briefly explains their operation.

Residential power systems

Residential dwellings almost always take supply from the low voltage distribution lines or cables that run past the dwelling. These operate at voltages of between 110 and 260 volts (phase-to-earth) depending upon national standards. A few decades ago small dwellings would be fed a single phase using a dedicated two-core service cable (one core for the active phase and one core for the neutral return). The active line would then be run through a main isolating switch in the fuse box and then split into one or more circuits to feed lighting and appliances inside the house. By convention, the lighting and appliance circuits are kept separate so the failure of an appliance does not leave the dwelling's occupants in the dark. All circuits would be fused with an appropriate fuse based upon the wire size used for that circuit. Circuits would have both an active and neutral wire with both the lighting and power sockets being connected in parallel. Sockets would also be provided with a protective earth. This would be made available to appliances to connect to any metallic casing. If this casing were to become live, the theory is the connection to earth would cause an RCD or fuse to trip—thus preventing the future electrocution of an occupant handling the appliance. Earthing systems vary between regions, but in countries such as the United Kingdom and Australia both the protective earth and neutral line would be earthed together near the fuse box before the main isolating switch and the neutral earthed once again back at the distribution transformer.

There have been a number of minor changes over the years to practice of residential wiring. Some of the most significant ways modern residential power systems in developed countries tend to vary from older ones include:

  • For convenience, miniature circuit breakers are now almost always used in the fuse box instead of fuses as these can easily be reset by occupants and, if of the thermomagnetic type, can respond more quickly to some types of fault.
  • For safety reasons, RCDs are now often installed on appliance circuits and, increasingly, even on lighting circuits.
  • Whereas residential air conditioners of the past might have been fed from a dedicated circuit attached to a single phase, larger centralised air conditioners that require three-phase power are now becoming common in some countries.
  • Protective earths are now run with lighting circuits to allow for metallic lamp holders to be earthed.
  • Increasingly residential power systems are incorporating microgenerators, most notably, photovoltaic cells.

Commercial power systems

Commercial power systems such as shopping centers or high-rise buildings are larger in scale than residential systems. Electrical designs for larger commercial systems are usually studied for load flow, short-circuit fault levels and voltage drop. The objectives of the studies are to assure proper equipment and conductor sizing, and to coordinate protective devices so that minimal disruption is caused when a fault is cleared. Large commercial installations will have an orderly system of sub-panels, separate from the main distribution board to allow for better system protection and more efficient electrical installation.

Typically one of the largest appliances connected to a commercial power system in hot climates is the HVAC unit, and ensuring this unit is adequately supplied is an important consideration in commercial power systems. Regulations for commercial establishments place other requirements on commercial systems that are not placed on residential systems. For example, in Australia, commercial systems must comply with AS 2293, the standard for emergency lighting, which requires emergency lighting be maintained for at least 90 minutes in the event of loss of mains supply. In the United States, the National Electrical Code requires commercial systems to be built with at least one 20 A sign outlet in order to light outdoor signage. Building code regulations may place special requirements on the electrical system for emergency lighting, evacuation, emergency power, smoke control and fire protection.

Power system management

Power system management varies depending upon the power system. Residential power systems and even automotive electrical systems are often run-to-fail. In aviation, the power system uses redundancy to ensure availability. On the Boeing 747-400 any of the four engines can provide power and circuit breakers are checked as part of power-up (a tripped circuit breaker indicating a fault). Larger power systems require active management. In industrial plants or mining sites a single team might be responsible for fault management, augmentation and maintenance. Where as for the electric grid, management is divided amongst several specialised teams.

Fault management

Fault management involves monitoring the behaviour of the power system so as to identify and correct issues that affect the system's reliability. Fault management can be specific and reactive: for example, dispatching a team to restring conductor that has been brought down during a storm. Or, alternatively, can focus on systemic improvements: such as the installation of reclosers on sections of the system that are subject to frequent temporary disruptions (as might be caused by vegetation, lightning or wildlife).

Maintenance and augmentation

In addition to fault management, power systems may require maintenance or augmentation. As often it is neither economical nor practical for large parts of the system to be offline during this work, power systems are built with many switches. These switches allow the part of the system being worked on to be isolated while the rest of the system remains live. At high voltages, there are two switches of note: isolators and circuit breakers. Circuit breakers are load-breaking switches where as operating isolators under load would lead to unacceptable and dangerous arcing. In a typical planned outage, several circuit breakers are tripped to allow the isolators to be switched before the circuit breakers are again closed to reroute power around the isolated area. This allows work to be completed on the isolated area.

Frequency and voltage management

Beyond fault management and maintenance one of the main difficulties in power systems is that the active power consumed plus losses must equal the active power produced. If load is reduced while generation inputs remain constant the synchronous generators will spin faster and the system frequency will rise. The opposite occurs if load is increased. As such the system frequency must be actively managed primarily through switching on and off dispatchable loads and generation. Making sure the frequency is constant is usually the task of a system operator. Even with frequency maintained, the system operator can be kept occupied ensuring:

  1. equipment or customers on the system are being supplied with the required voltage
  2. reactive power transmission is minimised (leading to more efficient operation)
  3. teams are dispatched and the system is switched to mitigate any faults
  4. remote switching is undertaken to allow for system works

Inequality (mathematics)

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