Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.[1] The definition was updated in the 1986 WHO "Ottawa Charter for Health Promotion" to say health is a "resource for everyday life, not the objective of living", and "health is a positive concept emphasizing social and personal resources, as well as physical capacities."[2].
// Aspects of Health "Mens sana in corpore sano" (Juvenal) Physical Health Main article: Physical fitness Physical fitness is good bodily health, and is the result of regular exercise, proper diet and nutrition, and proper rest for physical recovery. Height Main article: Human height A strong indicator of the health of populations is height, which is generally increased by improving nutrition and health care, and is also influenced by the standard of living and quality of life. Genetics is also a major factor in people's height. The study of human growth, its regulators, and its implications is known as Auxology. Mental health Main article: Mental health Mental health refers to a human individual's emotional and psychological well-being. Merriam-Webster defines mental health as "A state of emotional and psychological well-being in which an individual is able to use his or her cognitive and emotional capabilities, function in society, and meet the ordinary demands of everyday life." According to the World Health Organization, there is no one "official" definition of mental health. Cultural differences, subjective assessments, and competing professional theories all affect how "mental health" is defined. In general, most experts agree that "mental health" and "mental illness" are not opposites. In other words, the absence of a recognized mental disorder is not necessarily an indicator of mental health. One way to think about mental health is by looking at how effectively and successfully a person functions. Feeling capable and competent; being able to handle normal levels of stress, maintain satisfying relationships, and lead an independent life; and being able to "bounce back," or recover from difficult situations, are all signs of mental health. Encompassing your emotional, social, and—most importantly—your mental well-being; All these aspects—emotional, physical, and social—must function together to achieve overall health. Determinants of health Main article: Social determinants of health The LaLonde report suggested that there are four general determinants of health including human biology, environment, lifestyle, and healthcare services.[3] Thus, health is maintained and improved not only through the advancement and application of health science, but also through the efforts and intelligent lifestyle choices of the individual and society.
A major environmental factor is water quality, especially for the health of infants and children in developing countries.[4] Health maintenance Main article: Self-care Achieving health and remaining healthy is an active process. Effective strategies for staying healthy and improving one's health include the following elements: Nutrition Main article: Nutrition [Photo] [Photo] The updated USDA food pyramid, published in 2005, is a general nutrition guide for recommended food consumption. Nutrition is the science that studies how what people eat affects their health and performance, such as foods or food components that cause diseases or deteriorate health (such as eating too many calories, which is a major contributing factor to obesity, diabetes, and heart disease). The field of nutrition also studies foods and dietary supplements that improve performance, promote health, and cure or prevent disease, such as eating fibrous foods to reduce the risk of colon cancer, or supplementing with vitamin C to strengthen teeth and gums and to improve the immune system. Personal health depends partially on the social structure of one’s life. The maintenance of strong social relationships is linked to good health conditions, longevity, productivity, and a positive attitude. This is due to the fact that positive social interaction as viewed by the participant increases many chemical levels in the brain which are linked to personality and intelligence traits. Essentially this means that positive reinforcement from a third party make one more socially adept, in control, and relaxed physically and mentally, all of which are proven to effect the nervous system(UHF). Sports nutrition Main article: Sports nutrition Sports nutrition focuses on how food and dietary supplements affect athletic performance (during events), improvement (from training), and recovery (after events and training). One goal of sports nutrition is to maintain glycogen levels and prevent glycogen depletion. Another is to optimize energy levels and muscle tone. An athlete's strategy for winning an event may include a schedule for the entire season of what to eat, when to eat it, and in what precise quantities (before, during, after, and between workouts and events). Participants in endurance sports such as the full-distance triathlon actually eat during their races. Sports nutrition works hand-in-hand with sports medicine. Exercise Main article: Physical exercise [Photo] [Photo] A U.S. Marine emerges from the water upon completing the swimming leg of a triathlon. Exercise is the performance of movements in order to develop or maintain physical fitness and overall health. It is often directed toward also honing athletic ability or skill. Frequent and regular physical exercise is an important component in the prevention of some of the diseases of affluence such as cancer, heart disease, cardiovascular disease, Type 2 diabetes, obesity and back pain. Exercises are generally grouped into three types depending on the overall effect they have on the human body: Flexibility exercises such as stretching improve the range of motion of muscles and joints.Aerobic exercises such as walking and running focus on increasing cardiovascular endurance and muscle density.Anaerobic exercises such as weight training or sprinting increase muscle mass and strength. Physical exercise is considered important for maintaining physical fitness including healthy weight; building and maintaining healthy bones, muscles, and joints; promoting physiological well-being; reducing surgical risks; and strengthening the immune system. Proper nutrition is just as, if not more, important to health as exercise. When exercising it becomes even more important to have good diet to ensure the body has the correct ratio of macronutrients whilst providing ample micronutrients; this is to aid the body with the recovery process following strenuous exercise. When the body falls short of proper nutrition, it gets into starvation mode developed through evolution and depends onto fat content for survival. Research suggest that the production of thyroid hormones can be negatively affected by repeated bouts of dieting and calorie restriction[5]. Proper rest and recovery is also as important to health as exercise, otherwise the body exists in a permanently injured state and will not improve or adapt adequately to the exercise. The above two factors can be compromised by psychological compulsions (eating disorders such as exercise bulimia, anorexia, and other bulimias), misinformation, a lack of organization, or a lack of motivation. These all lead to a decreased state of health. Delayed Onset Muscle Soreness can occur after any exercise, particularly if the body is in an unconditioned state relative to that exercise and the exercise involves repetitive eccentric contractions. Hygiene Main article: Hygiene Hygiene is the practice of keeping the body clean to prevent infection and illness, and the avoidance of contact with infectious agents. Hygiene practices include bathing, brushing and flossing teeth, washing hands especially before eating, washing food before it is eaten, cleaning food preparation utensils and surfaces before and after preparing meals, and many others. This may help prevent infection and illness. By cleaning the body, dead skin cells are washed away with the germs, reducing their chance of entering the body. Stress management Main article: Stress management Prolonged psychological stress may negatively impact health, such as by weakening the immune system. See negative effects of the fight-or-flight response. Stress management is the application of methods to either reduce stress or increase tolerance to stress. Certain nootropics do both. Exercising to improve physical fitness, especially cardiovascular fitness, boosts the immune system and increases stress tolerance. Relaxation techniques are physical methods used to relieve stress. Examples include sexual intercourse, progressive relaxation, and fractional relaxation. Psychological methods include cognitive therapy, meditation, and positive thinking which work by reducing response to stress. Improving relevant skills and abilities builds confidence, which also reduces the stress reaction to situations where those skills are applicable. Reducing uncertainty, by increasing knowledge and experience related to stress-causing situations, has the same effect. Learning to cope with problems better, such as improving problem solving and time management skills, may also reduce stressful reaction to problems. Repeatedly facing an object of one's fears may also desensitize the fight-or-flight response with respect to that stimulus -- e.g., facing bullies may reduce fear of bullies. Health care Main article: Health care. See also Public health, below Health care is the prevention, treatment, and management of illness and the preservation of mental and physical well being through the services offered by the medical, nursing, and allied health professions. According to the World Health Organization, health care embraces all the goods and services designed to promote health, including “preventive, curative and palliative interventions, whether directed to individuals or to populations”.[6] The organized provision of such services may constitute a health care system. This can include a specific governmental organization such as the National Health Service in the UK, or a cooperation across the National Health Service and Social Services as in Shared Care. Natural health Main article: Natural health In alternative medicine, natural health is an eclectic self-care system of natural therapies concerned with building and restoring health and wellness via prevention and healthy lifestyles. Natural health includes breathing Buteyko Method, chiropractic, naturopathy, herbalism, homeopathy, massage therapy, relaxation techniques (e.g. Yoga, Tai Chi), accupuncture, sauna, aromatherapy, ayurveda medicine, and Kneipp therapy. Workplace wellness programs Main article: Workplace wellness Workplace wellness programs are recognized by an increasingly large number of companies for their value in improving the health and well-being of their employees, and for increasing morale, loyalty, and productivity. Workplace wellness programs can include things like onsite fitness centers, health presentations, wellness newsletters, access to health coaching, tobacco cessation programs and training related to nutrition, weight and stress management. Other programs may include health risk assessments, health screenings and body mass index monitoring. Mostly overseen or not mentioned is a group of determinants of health which could be called coincidence, hazard, luck or bad luck. These factors are quite important determinants of health but difficult to calculate. Public health Main article: Public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organised efforts and informed choices of society, organisations, public and private, communities and individuals." It is concerned with threats to the overall health of a community based on population health analysis. The population in question can be as small as a handful of people or as large as all the inhabitants of several continents (for instance, in the case of a pandemic). Public health has many sub-fields, but is typically divided into the categories of epidemiology, biostatistics and health services. Environmental, social and behavioral health, and occupational health, are also important fields in public health. The focus of public health intervention is to prevent rather than treat a disease through surveillance of cases and the promotion of healthy behaviors. In addition to these activities, in many cases treating a disease can be vital to preventing it in others, such as during an outbreak of an infectious disease. Vaccination programs and distribution of condoms are examples of public health measures. Role of science in health Main article: Health science Health science is the branch of science focused on health, and it includes many subdisciplines. There are two approaches to health science: the study and research of the human body and health-related issues to understand how humans (and animals) function, and the application of that knowledge to improve health and to prevent and cure diseases. Where health knowledge comes from Health research builds primarily on the basic sciences of biology, chemistry, and physics as well as a variety of multidisciplinary fields (for example medical sociology). Some of the other primarily research-oriented fields that make exceptionally significant contributions to health science are biochemistry, epidemiology, and genetics. Putting health knowledge to use Applied health sciences also endeavor to better understand health, but in addition they try to directly improve it. Some of these are: biomedical engineering, biotechnology, nursing, nutrition, pharmacology, pharmacy, public health (see below), psychology, physical therapy, and medicine. The provision of services to maintain or improve people's health is referred to as health care (see above). [edit] See also Environmental health General fitness training Physical fitnessList of basic exercise topics Health care Health care deliveryHealth educationHealth profession Hygiene Mental hygieneOral hygieneSleep hygiene Longevity List of life extension related topics Medicine Alternative medicineTraditional Chinese medicineAdolescent medicine Mental healthNutrition VitaminsMineralsHealthy dietList of basic nutrition topics Public health Population health Reproductive health Sexuality educationSexually transmitted diseaseBirth controlMaternal health World Health Organization References ^ WHO. "Constitution of the World Health Organization" World Health Organization; 2006^ WHO. [1], The Ottawa Charter for Health Promotion, Ottawa, 1986.^ Lalonde, Marc. "A New Perspective on the Health of Canadians." Ottawa: Minister of Supply and Services; 1974.^ The UN World Water Development Report | Facts and Figures | Meeting basic needs^ Common fitness mistakes people make Stay Fit retrieved on 11-13-2006^ World Heath Organization Report. (2000). Chapter 1: Why do health systems matter?. WHO. Retrieved on 2008-02-19. WHO (1979) Health for all.WHO (1980) WHO Chr., 34(2)80WHO (1986) Concepts of Health Behavior Research, Reg. Health Paper No.13, SEARO, New DelhiWHO (1978) Health for all.UNDP, Human Development Report 1999, Oxford University PressUNICEF,2001 State of world's children, 2001WHO (1979) Health for all.Evang, K. (1967); In health of mankind; Ciba foundation; 100th symposium, Churchill, LondonLast, J.M (1983) A Dictionary of Epidemiology, Oxford University PressRaska, K (1966), WHO Chr., 20, 315 External links [Photo] Look up Health in
Wiktionary, the free dictionary. World Health OrganizationHealth On the Net FoundationMy World Health
Entertainment is an activity designed to give pleasure or relaxation to an audience. This audience may participate in the entertainment passively as in watching opera or a movie, or actively as in games.
The playing of sports and reading of literature are usually included in entertainment, but these are often called recreation, because they involve some active participation beyond mere leisure
The industry that provides entertainment is called the entertainment industry.
Examples of entertainment
Animation
Animation provides moving images that are generated by an artist, in contrast to the live action normally used in motion pictures. It is typically accompanied by a sound track consisting of recordings of live actors. Animation is often used in computer-based forms of entertainment.
Cartoons are a comedic form of animation. Anime or TV manga refers to animation originating from Japan in the Occidental use of the word. In Japan the word refers to all animation. It may contain adult themes and futuristic locations.
Cinema
Cinema provides moving pictures as an art form. Cinema may also be called films or movies. A film produces an illusion of motion by presenting a series of individual image frames in rapid succession. Films are produced by a crew that handle the cameras, sets and lighting. The cast consists of actors who appear in front of the camera and follow a script. After the film has been shot, it is edited then distributed to theaters or television studios for viewing.
Theatre
Theatre encompasses live performance such as plays, musicals, farces, monologues and pantomimes.
Circus
Circus acts include acrobats, clowns, trained animals, trapeze acts, hula hoopers, tightrope walkers, jugglers, unicyclists and other stunt-oriented artists.
circuses are a great place for families :)
Comedy
Comedy provides laughter and amusement. The audience is taken by surprise, by the parody or satire of an unexpected effect or an opposite expectations of their cultural beliefs. Slapstick film, one-liner joke, observational humor are forms of comedy which have developed since the early days of jesters and traveling minstrels.
Comics
Comics comprise of text and drawings which convey an entertaining narrative.Several famous comics revolve around super heroes such as Superman, Batman. Marvel Comics and DC Comics are two publishers of comic books. Manga is the Japanese word for comic and print cartoons.
Caricature is a graphical entertainment. The purpose may vary from merely putting smile on the viewers face, to raising social awareness, to highlighting the moral vices of a person being caricaturised.
Dance
Dance refers to movement of the body, usually rhythmic and to music, used as a form of expression, social interaction or presented in a spiritual or performance setting. Dance includes ballet, cancan, charleston, Highland fling, folk dance, sun dance, modern dance, polka and many more.
Reading
Reading comprises the interpretation of written symbols. An author, poet or playwright sets out a composition for publication to provide education or diversion for the reader. The format includes paperback or hard cover books, magazines, periodicals, puzzle books, crossword magazines and coloring books. Fantasy, horror, science fiction and mystery are forms of reading entertainment.
Games
Games provides relaxation and diversion usually following a rule set. Games may be played by one person for their own entertainment, or by a group games. Games may be played for achievement or monetary benefit such as gambling or bingo. Racing, chess or checkers may develop physical or mental prowess. Games may be geared for children, or may be played outdoors such as lawn bowling. Equipment may be necessary to play the game such as a deck of cards for card games, or a board and markers for board games such as Monopoly, or backgammon. A few may be ball games, Blind man's bluff, board games, card games, children's games, Croquet, Frisbee, Hide and seek, Number games, Paintball, and Video games to name a few.
Music
Music is an art form combining rhythm, melody, harmony and/or vocals for entertainment, ceremonial or religious purposes.
Other forms of entertainment
See also
- Main list: List of basic entertainment topics
External links
Footnotes
- ^ entertainment - Definitions from Dictionary.com. Lexico Publishing Group, LLC. (2007). Retrieved on 2007-11-30.
- ^ cartoon - Definitions from Dictionary.com. Lexico Publishing Group, LLC. (2007). Retrieved on 2007-11-30.
- ^ anime - Definitions from Dictionary.com. Lexico Publishing Group, LLC. (2007). Retrieved on 2007-11-30.
- ^ Harper, Douglas gfg (2001). fdgfg cinema- Definitions from Dictionary.com. rOnline Etymology Dictionary fd fdf. Lexico Publishing Group, LLC.. Retrieved on 2007-11-30.
- ^ Hoh, Lavahn G. (2004). The Circus in America: 1793–1940. The Institute for Advanced Technology in the Humanities. University of Virginia. Retrieved on 2007-11-30.
- ^ comedy. From: The Columbia Encyclopedia, Sixth Edition. HighBeam Research, Inc. (2007). Retrieved on 2007-11-30.
- ^ comic strip comic strip. Britannica Online Encyclopedia. Encyclopædia Britannica, Inc. (2007). Retrieved on 2007-11-30.
- ^ britannica.
- ^ Encyclopedia: Dance — Infoplease.com. Pearson Education, publishing as Infoplease (2000–2007). Retrieved on 2007-11-30.
- ^ reading - Encyclopedia.com. HighBeam Research, Inc (2007). Retrieved on 2007-11-30.
- ^ Games - MSN Encarta. Microsoft (2007). Retrieved on 2007-11-30.
- ^ music - definition of music by the Free Online Dictionary, Thesaurus and Encyclopedia. Farlex, Inc. (2007). Retrieved on 2007-11-3
Aviation encompasses all the activities relating to airborne devices created by human ingenuity, generally known as aircraft. These activities include the organizations and regulatory bodies as well as the personnel related with the operation of aircraft and the industries involved in airplane manufacture, development, and design. [1]
History
Many cultures have built devices that travel through the air, from the earliest projectiles such as stones and spears, to more sophisticated buoyant or aerodynamic devices such as the mechanical pigeon of Archytas in ancient Greece[2][3], the boomerang in Australia, the hot air Kongming lantern, and kites. There are early legends of human flight such as the story of Icarus, and later, more credible claims of short-distance human flights including a kite flight by Yuan Huangtou in China, and the parachute flight and controlled glider flight of Abbas Ibn Firnas (Armen Firman).
The modern age of aviation began with the first untethered human lighter-than-air flight on November 21, 1783, in a hot air balloon designed by the Montgolfier brothers.
The practicality of balloons was limited because they could only travel downwind. It was immediately recognized that a steerable, or dirigible, balloon was required. Jean-Pierre Blanchard flew the first human-powered dirigible in 1784 and crossed the English Channel in one in 1785. Subsequent early dirigible developments included machine-powered propulsion (Henri Giffard, 1852), rigid frames (David Schwarz, 1896), and improved speed and maneuverability (Alberto Santos-Dumont, 1901).
While there are many competing claims for the earliest powered, heavier-than-air flight, the most widely-accepted date is December 17, 1903 by the Wright brothers, though their aircraft was impractical to fly for more than a short distance because of control problems. The widespread adoption of ailerons made aircraft much easier to manage, and only a decade later, at the start of World War I, heavier-than-air powered aircraft had become practical for reconnaissance, artillery spotting, and even attacks against ground positions.
Aircraft began to transport people and cargo as designs grew larger and more reliable. In contrast to small non-rigid blimps, giant rigid airships became the first aircraft to transport passengers and cargo over great distances. The best known aircraft of this type were manufactured by the German Zeppelin company.
The most successful Zeppelin was the Graf Zeppelin. It flew over one million miles, including an around-the-world flight in August of 1929. However, the dominance of the Zeppelins over the airplanes of the that period, which had a range of only a few hundred miles, was diminishing as airplane design advanced. The "Golden Age" of the airships ended on June 6, 1937 when the Hindenburg caught fire killing 36 people. Although there have been periodic initiatives to revive their use, airships have seen only niche application since that time.
Great progress was made in the field of aviation during the 1920s and 1930s, such as Charles Lindbergh's transatlantic flight in 1927. One of the most successful designs of this period was the Douglas DC-3 which became the first airliner that was profitable carrying passengers exclusively, starting the modern era of passenger airline service. By the beginning of World War II, many towns and cities had built airports, and there were numerous qualified pilots available. The war brought many innovations to aviation, including the first jet aircraft and the first liquid-fueled rockets.
After WWII, especially in North America, there was a boom in general aviation, both private and commercial, as thousands of pilots were released from military service and many inexpensive war-surplus transport and training aircraft became available. Manufacturers such as Cessna, Piper, and Beechcraft expanded production to provide light aircraft for the new middle class market.
By the 1950s, the development of civil jets grew, beginning with the de Havilland Comet, though the first widely-used passenger jet was the Boeing 707, because it was much more economical than other planes at the time. At the same time, turboprop propulsion began to appear for smaller commuter planes, making it possible to serve small-volume routes in a much wider range of weather conditions.
Yuri Gagarin was the first human to travel to space on April 12, 1961, while Neil Armstrong was the first to set foot on the moon on July 21, 1969.
Since the 1960s, composite airframes and quieter, more efficient engines have become available, but the most important innovations have taken place in instrumentation and control. The arrival of solid-state electronics, the Global Positioning System, satellite communications, and increasingly small and powerful computers and LED displays, have dramatically changed the cockpits of airliners and, increasingly, of smaller aircraft as well. Pilots can navigate much more accurately and view terrain, obstructions, and other nearby aircraft on a map or through synthetic vision, even at night or in low visibility.
On June 21, 2004, SpaceShipOne became the first privately funded aircraft to make a spaceflight, opening the possibility of an aviation market outside the earth's atmosphere. Meanwhile, flying prototypes of aircraft powered by alternative fuels, such as ethanol, electricity, and even solar energy, are becoming more common and may soon enter the mainstream, at least for light aircraft.
Civil aviation
Civil aviation includes all non-military flying, both general aviation and scheduled air transport.
Air transport
There are five major manufacturers of civil transport aircraft:
- Airbus, based in Europe
- Boeing, based in the United States
- Bombardier, based in Canada
- Embraer, based in Brazil
- Tupolev, based in Russia (scheduled to be merged into the United Aircraft Building Corporation)
Boeing, Airbus, and Tupolev concentrate on wide-body and narrow-body jet airliners, while Bombardier and Embraer concentrate on regional airliners. Large networks of specialized parts suppliers from around the world support these manufacturers, who sometimes provide only the initial design and final assembly in their own plants. The Chinese ACAC consortium will also soon enter the civil transport market with its ACAC ARJ21 regional jet.[4]
Until the 1970s, most major airlines were flag carriers, sponsored by their governments and heavily protected from competition. Since then, open skies agreements have resulted in increased competition and choice for consumers, coupled with falling prices for airlines. The combination of high fuel prices, low fares, high salaries, and crises such as the September 11, 2001 attacks and the SARS epidemic have driven many older airlines to government-bailouts, bankruptcy or mergers. At the same time, low-cost carriers such as Ryanair and Southwest have flourished.
General aviation
General aviation includes all non-scheduled civil flying, both private and commercial. General aviation may include business flights, air charter, private aviation, flight training, ballooning, parachuting, gliding, hang gliding, aerial photography, foot-launched powered hang gliders, air ambulance, crop dusting, charter flights, traffic reporting, police air patrols and forest fire fighting.
Each country regulates aviation differently, but general aviation usually falls under different regulations depending on whether it is private or commercial and on the type of equipment involved.
Many small aircraft manufacturers, including Cessna, Piper, Diamond, Mooney, Cirrus Design, Raytheon, and others serve the general aviation market, with a focus on private aviation and flight training.
The most important recent developments for small aircraft (which form the bulk of the GA fleet) have been the introduction of advanced avionics (including GPS) that were formerly found only in large airliners, and the introduction of composite materials to make small aircraft lighter and faster. Ultralight and homebuilt aircraft have also become increasingly popular for recreational use, since in most countries that allow private aviation, they are much less expensive and less heavily regulated than certified aircraft.
Military aviation
Simple balloons were used as surveillance aircraft as early as the 18th century. Over the years, military aircraft have been built to meet ever increasing capability requirements. Manufacturers of military aircraft compete for contracts to supply their government's arsenal. Aircraft are selected based on factors like cost, performance, and the speed of production.
Types of military aircraft
- Fighter aircraft's primary function is to destroy other aircraft. (e.g. Sopwith Camel, A6M Zero, F-16, MiG-29, Su-27, F-22).
- Ground attack aircraft are used against tactical earth-bound targets. (e.g. Junkers Stuka diver bomber, Ilyushin Il-2 ,J-22 Orao, Sukhoi Su-25, and the A-10).
- Bombers are generally used against more strategic targets. (e.g. Zeppelin, B-29 Superfortress, Tu-22, Dassault Mirage IV, and the B-2 Spirit)
- Cargo transport aircraft are used to transport hardware and personnel, such as the C-17 Globemaster III or C-130 Hercules.
- Surveillance aircraft are used for reconnaissance (e.g. Rumpler Taube, de Havilland Mosquito, U-2, and MiG-25R).
- Helicopters are used for assault support, cargo transport and close air support.
Air Traffic Control (ATC)
Air traffic control (ATC) involves communication with aircraft to help maintain separation — that is, they ensure that aircraft are sufficiently far enough apart horizontally or vertically for no risk of collision. Controllers may co-ordinate position reports provided by pilots, or in high traffic areas (such as the United States) they may use RADAR to see aircraft positions.
There are generally four different types of ATC:
- centre controllers, who control aircraft enroute between airports
- control towers (including tower, ground control, clearance delivery, and other services), which control aircraft within a small distance (typically 10-15 km horizontal, and 1,000 m vertical) of an airport.
- oceanic controllers, who control aircraft over international waters between continents, generally without radar service.
- terminal controllers, who control aircraft in a wider area (typically 50-80 km) around busy airports.
ATC is especially important for aircraft flying under Instrument flight rules (IFR), where they may be in weather conditions that do not allow the pilots to see other aircraft. However, in very high-traffic areas, especially near major airports, aircraft flying under Visual flight rules (VFR) are also required to follow instructions from ATC.
In addition to separation from other aircraft, ATC may provide weather advisories, terrain separation, navigation assistance, and other services to pilots, depending on their workload.
ATC does not control all flights. The majority of VFR flights in North America are not required to talk to ATC (unless they are passing through a busy terminal area or using a major airport), and in many areas, such as northern Canada, ATC services are not available even for IFR flights at lower altitudes.
Environmental impact
Like all activities involving combustion, operating powered aircraft (from airliners to hot air balloons) releases greenhouse gases such as carbon dioxide (CO2), soot, and other pollutants into the atmosphere. In addition, there are environmental impacts specific to aviation:
- Aircraft operating at high altitudes near the tropopause (mainly large jet airliners) emit aerosols and leave contrails, both of which can increase cirrus cloud formation — cloud cover may have increased by up to 0.2% since the birth of aviation.[5]
- Aircraft operating at high altitudes near the tropopause can also release chemicals that interact with greenhouse gases at those altitudes, particularly nitrogen compounds, which interact with ozone, increasing ozone concentrations.[6][7]
- Most light piston aircraft burn avgas, which contains tetra-ethyl lead (TEL), a highly-toxic substance that can cause soil contamination at airports. Some lower-compression piston engines can operate on unleaded mogas, and turbine engines and diesel engines — neither of which requires lead — are appearing on some newer light aircraft.
Notes
- ^ Babcock Gover, Philip (1990). Webster's Third New International Dictionary. Merriam-Webster. ISBN 978-0877792017.
- ^ Archytas of Tarentum, Technology Museum of Thessaloniki, Macedonia, Greece
- ^ Automata history [1]
- ^ China's Aircraft Industry Gets Off the Ground - TIME
- ^ Aviation and the Global Atmosphere (IPCC)
- ^ Lin, X.; Trainer, M. and Liu, S.C., (1988). "On the nonlinearity of the tropospheric ozone production.". Journal of Geophysical Research 93: 15879–15888.
- ^ Grewe, V.; D. Brunner, M. Dameris, J. L. Grenfell, R. Hein, D. Shindell, J. Staehelin (July 2001). "Origin and variability of upper tropospheric nitrogen oxides and ozone at northern mid-latitudes". Atmospheric Environment 35 (20): 3421-3433. doi:.
See also
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