1.
Personal protective equipment
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Personal protective equipment refers to protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearers body from injury or infection. The hazards addressed by protective equipment include physical, electrical, heat, chemicals, biohazards, Protective equipment may be worn for job-related occupational safety and health purposes, as well as for sports and other recreational activities. Protective clothing is applied to categories of clothing, and protective gear applies to items such as pads, guards, shields, or masks. PPE is needed there are hazards present. PPE has the limitation that it does not eliminate the hazard at source. Any item of PPE imposes a barrier between the wearer/user and the working environment and this can create additional strains on the wearer, impair their ability to carry out their work and create significant levels of discomfort. Any of these can discourage wearers from using PPE correctly, therefore placing them at risk of injury, ill-health or, under extreme circumstances, death. Good ergonomic design can help to minimise these barriers and can help to ensure safe. Practices of occupational safety and health can use hazard controls and interventions to mitigate workplace hazards, the hierarchy of hazard controls provides a policy framework which ranks the types of hazard controls in terms of absolute risk reduction. At the top of the hierarchy are elimination and substitution, which remove the hazard entirely or replace the hazard with a safer alternative. If elimination or substitution measures cannot apply, engineering controls and administrative controls, Personal protective equipment ranks last on the hierarchy of controls, as the workers are regularly exposed to the hazard, with a barrier of protection. The hierarchy of controls is important in acknowledging that, while personal protective equipment has tremendous utility, Personal protective equipment can be categorized by the area of the body protected, by the types of hazard, and by the type of garment or accessory. The protective attributes of each piece of equipment must be compared with the expected to be found in the workplace. More breathable types of protective equipment may not lead to more contamination. Respirators serve to protect the user from breathing in contaminants in the air, there are two main types of respirators. One type functions by filtering out chemicals and gases, or airborne particles, the filtration may be either passive or active. Gas masks and particulate respirators are examples of type of respirator. A second type protects users by providing clean, respirable air from another source and this type includes airline respirators and self-contained breathing apparatus
2.
Light
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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to light, which is visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m. This wavelength means a range of roughly 430–750 terahertz. The main source of light on Earth is the Sun, sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the used by living things. Historically, another important source of light for humans has been fire, with the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence, for example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey. Visible light, as all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term sometimes refers to electromagnetic radiation of any wavelength. In this sense, gamma rays, X-rays, microwaves and radio waves are also light, like all types of light, visible light is emitted and absorbed in tiny packets called photons and exhibits properties of both waves and particles. This property is referred to as the wave–particle duality, the study of light, known as optics, is an important research area in modern physics. Generally, EM radiation, or EMR, is classified by wavelength into radio, microwave, infrared, the behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths, when EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries. There exist animals that are sensitive to various types of infrared, infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it, above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the eye cannot detect the very short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, various sources define visible light as narrowly as 420 to 680 to as broadly as 380 to 800 nm
3.
Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
4.
Heat
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In physics, heat is the amount of energy flowing from one body to another spontaneously due to their temperature difference, or by any means other than through work or the transfer of matter. Thus, energy exchanged as heat during a process changes the energy of each body by equal. The sign of the quantity of heat can indicate the direction of the transfer, for example from system A to system B, negation indicates energy flowing in the opposite direction. While heat flows spontaneously from hot to cold, it is possible to construct a heat pump or refrigeration system that does work to increase the difference in temperature between two systems, conversely, a heat engine reduces an existing temperature difference to do work on another system. Heat is a consequence of the motion of particles. When heat is transferred between two objects or systems, the energy of the object or systems particles increases, as this occurs, the arrangement between particles becomes more and more disordered. In other words, heat is related to the concept of entropy, historically, many energy units for measurement of heat have been used. The standards-based unit in the International System of Units is the joule, Heat is measured by its effect on the states of interacting bodies, for example, by the amount of ice melted or a change in temperature. The quantification of heat via the change of a body is called calorimetry. In calorimetry, sensible heat is defined with respect to a specific chosen state variable of the system, sensible heat causes a change of the temperature of the system while leaving the chosen state variable unchanged. Heat transfer that occurs at a constant system temperature but changes the state variable is called latent heat with respect to the variable, for infinitesimal changes, the total incremental heat transfer is then the sum of the latent and sensible heat. Physicist James Clerk Maxwell, in his 1871 classic Theory of Heat, was one of many who began to build on the established idea that heat has something to do with matter in motion. This was the idea put forth by Benjamin Thompson in 1798. One of Maxwells recommended books was Heat as a Mode of Motion, Maxwell outlined four stipulations for the definition of heat, It is something which may be transferred from one body to another, according to the second law of thermodynamics. It is a quantity, and so can be treated mathematically. It cannot be treated as a substance, because it may be transformed into something that is not a material substance. Heat is one of the forms of energy and this was the way of the historical pioneers of thermodynamics. Maxwell writes that convection as such is not a purely thermal phenomenon, in thermodynamics, convection in general is regarded as transport of internal energy
5.
Ball
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A ball is a round object with various uses. It is used in games, where the play of the game follows the state of the ball as it is hit. Balls can also be used for activities, such as catch, marbles. Balls made from hard-wearing materials are used in engineering applications to very low friction bearings. Black-powder weapons use stone and metal balls as projectiles, although many types of balls are today made from rubber, this form was unknown outside the Americas until after the voyages of Columbus. The Spanish were the first Europeans to see bouncing rubber balls which were employed most notably in the Mesoamerican ballgame, balls used in various sports in other parts of the world prior to Columbus were made from other materials such as animal bladders or skins, stuffed with various materials. As balls are one of the most familiar spherical objects to humans, no Old English representative of any of these is known. If ball- was native in Germanic, it may have been a cognate with the Latin foll-is in sense of a blown up or inflated. In the later Middle English spelling balle the word coincided graphically with the French balle ball, French balle is assumed to be of Germanic origin, itself, however. In Ancient Greek the word πάλλα for ball is attested besides the word σφαίρα, a ball, as the essential feature in many forms of gameplay requiring physical exertion, must date from the very earliest times. A rolling object appeals not only to a baby but to a kitten. Some form of game with a ball is found portrayed on Egyptian monuments, in Homer, Nausicaa was playing at ball with her maidens when Odysseus first saw her in the land of the Phaeacians. And Halios and Laodamas performed before Alcinous and Odysseus with ball play, of regular rules for the playing of ball games, little trace remains, if there were any such. Pollux mentions a game called episkyros, which has often been looked on as the origin of football and it seems to have been played by two sides, arranged in lines, how far there was any form of goal seems uncertain. Among the Romans, ball games were looked upon as an adjunct to the bath, and were graduated to the age and health of the bathers and this was struck from player to player, who wore a kind of gauntlet on the arm. These games are known to us through the Romans, though the names are Greek, the various modern games played with a ball or balls and subject to rules are treated under their various names, such as polo, cricket, football, etc. Several sports use a ball in the shape of a prolate spheroid, Ball Buckminster Fullerene Football Kickball Marbles Penny floater Prisoner Ball Shuttlecock Super Ball
6.
Goggles
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Goggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in laboratories and in woodworking. They are often used in sports as well, and in swimming. Goggles are often worn when using tools such as drills or chainsaws to prevent flying particles from damaging the eyes. Many types of goggles are available as prescription goggles for those with vision problems, the Inuit and Yupik people carved Inuit snow goggles from caribou antler, wood, and shell to help prevent snow blindness. The goggles were curved to fit the users face and had a groove cut in the back to allow for the nose. A long thin slit was cut through the goggles to allow in an amount of light. The goggles were held to the head by a made of caribou sinew. In the early 20th century, goggles were worn by drivers of uncovered cars to prevent irritation of the eyes by dust or wind, the first pilot to wear goggles was probably Charles Manly in his failed attempt to fly Samuel Langleys aerodrome in 1903. The requirements for goggles varies depending on the use, some examples, Cold weather, Most modern cold-weather goggles have two layers of lens to prevent the interior from becoming foggy. With only a lens, the interior water vapor condenses onto the lens because the lens is colder than the vapor. The reasoning behind dual layer lens is that the lens will be warm while the outer lens will be cold. As long as the temperature of the lens is close to that of the interior water vapor. Swimming, Must be watertight to prevent water, such as water when swimming in the ocean, or chlorinated water when swimming in a pool. Allows swimmers to see clearly underwater and they will not be usable more than a few feet underwater, because the water pressure will press them tightly against the face. Examples of these include the Swedish goggles, power tools, Must be made of an unbreakable material that prevents chunks of metal, wood, plastic, concrete, and so on from hitting or piercing the eye. Usually has some sort of ventilation to prevent sweat from building up inside the goggles, blowtorch goggles, These protect the eyes from glare and flying sparks and hot metal splashes while using or near a blowtorch. They are not the filters for arc welding
7.
Swimming
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Human swimming is the self-propulsion of a person through water or another liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs, the body, humans can hold their breath underwater and undertake rudimentary locomotive swimming within weeks of birth, as an evolutionary response. Swimming is consistently among top public recreational activities, and in some countries, as a formalized sport, swimming features in a range of local, national, and international competitions, including every modern summer Olympics, which takes place every four years. Swimming relies on the buoyancy of the human body. On average, the body has a density of 0.98 compared to water. However, buoyancy varies on the basis of body composition and the salinity of the water. Higher levels of fat and saltier water both lower the relative density of the body and increase its buoyancy. Since the human body is slightly less dense than water, water supports the weight of the body during swimming. As a result, swimming is “low-impact” compared to land such as running. The density and viscosity of water also create resistance for objects moving through the water, Swimming strokes use this resistance to create propulsion, but this same resistance also generates drag on the body. Hydrodynamics is important to stroke technique for swimming faster, and swimmers who want to swim faster or tire less try to reduce the drag of the motion through the water. Just before plunging into the pool, swimmers may perform such as squatting. Squatting helps in enhancing a swimmer’s start by warming up the thigh muscles, human babies demonstrate an innate swimming or diving reflex from newborn until the age of approximately 6 months. Other mammals also demonstrate this phenomenon, Swimming can be undertaken using a wide range of styles, known as strokes, and these strokes are used for different purposes, or to distinguish between classes in competitive swimming. It is not necessary to use a stroke for propulsion through the water. There are four main strokes used in competition and recreation swimming, the front crawl, also known as freestyle, the breaststroke, the backstroke, competitive swimming in Europe started around 1800, mostly using the breaststroke. In 1873, John Arthur Trudgen introduced the trudgen to Western swimming competitions, Swimming has been recorded since prehistoric times, and the earliest records of swimming date back to Stone Age paintings from around 7,000 years ago. Written references date from 2000 BC, some of the earliest references include the Epic of Gilgamesh, the Iliad, the Odyssey, the Bible, Beowulf, and other sagas
8.
Salt
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Salt is present in vast quantities in seawater, where it is the main mineral constituent. The open ocean has about 35 grams of solids per litre, Salt is essential for life in general, and saltiness is one of the basic human tastes. The tissues of animals contain larger quantities of salt than do plant tissues, Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation. Salt was also prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites, Egyptians, and the Indians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, the scarcity and universal need for salt has led nations to go to war over it and use it to raise tax revenues. Salt is used in ceremonies and has other cultural significance. Salt is processed from salt mines, or by the evaporation of seawater or mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine, and is used in industrial processes including the manufacture of polyvinyl chloride, plastics, paper pulp. Of the annual production of around two hundred million tonnes of salt, only about 6% is used for human consumption. Other uses include water conditioning processes, de-icing highways, and agricultural use, edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, sodium is an essential nutrient for human health via its role as an electrolyte and osmotic solute. Excessive salt consumption can increase the risk of diseases, such as hypertension, in children. Such health effects of salt have long been studied, accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods. The World Health Organization recommends that adults should consume less than 2,000 mg of sodium, humans have always tended to build communities either around sources of salt, or where they can trade for it. All through history the availability of salt has been pivotal to civilization, the word salary comes from the Latin word for salt because the Roman Legions were sometimes paid in salt. The Natron Valley was a key region that supported the Egyptian Empire to its north, because it supplied it with a kind of salt that came to be called by its name, natron. Even before this, what is now thought to have been the first city in Europe is Solnitsata, in Bulgaria, even the name Solnisata means salt works. A very ancient salt-works operation has been discovered at the Poiana Slatinei archaeological site next to a spring in Lunca, Neamț County
9.
Chlorine
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Chlorine is a chemical element with symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the table and its properties are mostly intermediate between them. Chlorine is a gas at room temperature. It is an extremely reactive element and a strong oxidising agent, among the elements, it has the highest electron affinity, the most common compound of chlorine, sodium chloride, has been known since ancient times. Around 1630, chlorine gas was first synthesised in a chemical reaction, Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be an element, and this was confirmed by Sir Humphry Davy in 1810. Because of its reactivity, all chlorine in the Earths crust is in the form of ionic chloride compounds. It is the second-most abundant halogen and twenty-first most abundant chemical element in Earths crust and these crustal deposits are nevertheless dwarfed by the huge reserves of chloride in seawater. Elemental chlorine is produced from brine by electrolysis. The high oxidising potential of chlorine led to the development of commercial bleaches and disinfectants. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used directly in swimming pools to keep them clean. Elemental chlorine at high concentrations is extremely dangerous and poisonous for all living organisms, in the form of chloride ions, chlorine is necessary to all known species of life. Other types of compounds are rare in living organisms. In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion, small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils as part of the immune response against bacteria. Its importance in food was very well known in antiquity and was sometimes used as payment for services for Roman generals. Around 1630, chlorine was recognized as a gas by the Flemish chemist, the element was first studied in detail in 1774 by Swedish chemist Carl Wilhelm Scheele, and he is credited with the discovery. He called it dephlogisticated muriatic acid air since it is a gas and he failed to establish chlorine as an element, mistakenly thinking that it was the oxide obtained from the hydrochloric acid. He named the new element within this oxide as muriaticum, in 1809, Joseph Louis Gay-Lussac and Louis-Jacques Thénard tried to decompose dephlogisticated muriatic acid air by reacting it with charcoal to release the free element muriaticum
10.
Sunglasses
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Sunglasses or sun glasses are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can sometimes function as a visual aid, as variously termed spectacles or glasses exist. In the early 20th century, they were known as sun cheaters. The American Optometric Association recommends sunglasses whenever a person is in the sun. to protect the eyes from ultraviolet radiation and blue light, Sunglasses have long been associated with celebrities and film actors primarily from a desire to mask their identity. Since the 1940s, sunglasses have been popular as a fashion accessory, in prehistoric and historic time, Inuit peoples wore flattened walrus ivory glasses, looking through narrow slits to block harmful reflected rays of the sun. It is said that the Roman emperor Nero liked to watch gladiator fights with emeralds and these, however, appear to have worked rather like mirrors. Sunglasses made from flat panes of smoky quartz, which offered no corrective powers, ancient documents describe the use of such crystal sunglasses by judges in ancient Chinese courts to conceal their facial expressions while questioning witnesses. James Ayscough began experimenting with tinted lenses in spectacles in the mid-18th century and these were not sunglasses as that term is now used, Ayscough believed that blue- or green-tinted glass could correct for specific vision impairments. Protection from the Suns rays was not a concern for him, in the early 1920s, the use of sunglasses started to become more widespread, especially among movie stars. The stereotype persisted long after improvements in quality and the introduction of ultraviolet filters had eliminated this problem. Inexpensive mass-produced sunglasses made from celluloid were first produced by Sam Foster in 1929, Foster found a ready market on the beaches of Atlantic City, New Jersey, where he began selling sunglasses under the name Foster Grant from a Woolworth on the Boardwalk. By 1938, Life magazine wrote of how sunglasses were a new fad for wear on city streets, a favorite affectation of thousands of women all over the U. S. It stated that 20 million sunglasses were sold in the United States in 1937, Polarized sunglasses first became available in 1936, when Edwin H. Land began experimenting with making lenses with his patented Polaroid filter, at present, Xiamen, China, is the worlds largest producer of sunglasses, with its port exporting 120 million pairs each year. Sunglasses can improve comfort and visual clarity by protecting the eye from glare. Various types of disposable sunglasses are dispensed to patients after receiving mydriatic eye drops during eye examinations, the lenses of polarized sunglasses reduce glare reflected at some angles off shiny non-metallic surfaces, such as water. They allow wearers to see into water when only surface glare would otherwise be seen, Sunglasses offer protection against excessive exposure to light, including its visible and invisible components. Sunglasses that meet this requirement are often labeled as UV400 and this is slightly more protection than the widely used standard of the European Union, which requires that 95% of the radiation up to only 380 nm must be reflected or filtered out
11.
Ultraviolet
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Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is also produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan, freckling and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays. Under some conditions, children and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects, mammals, and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV also allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
