Outdoor recreation or outdoor activity refers to recreation engaged in out of doors, most in natural settings. The activities themselves — such as fishing, hunting and horseback riding — characteristically determine where they are practiced, they are pursued variously for enjoyment, challenge, spiritual renewal, an opportunity to partake in Nature. Though the activities are inherently lean to sports they nonetheless do not all demand that a participant be an athlete, competition is less stressed than in individual or team sports organized into opposing squads in pursuit of a trophy or championship; when the activity involves exceptional excitement, physical challenge, or risk, it is sometimes referred to as "adventure recreation" or "adventure training", rather than an extreme sport. Other traditional examples of outdoor recreational activities include hiking, mountaineering, canoeing, kayaking, rock climbing, sailing, sky diving and surfing; as new pursuits hybrids of prior ones, they gain their own identities, such as coasteering and fastpacking.
Outdoor recreation consists of a range of various outdoor activities. Although many are considered sports, participants need not associate with teams, competitions or clubs. Activities include backpacking, canyoning, climbing, hill walking, hunting and rafting. Arguably, broader groupings include water sports, snow sports, horseback riding; the outdoors as a physical or social setting may meet the needs of physical health, self-sufficiency, risk-taking, the building of social ties, the needs of achievement. The outdoors can be an environment in which people "show what they can do". Pleasurable appreciation encourages experiences of being "let in on nature's show". Enhancement of inner perceptual and/or spiritual life may be experienced through outdoor activities and outdoor-related activities such as nature study, aesthetic contemplation, painting, archeological or historical research, indigenous culture among others; these activities may be physically rewarding. Outdoor activities may be pursued for the purposes of finding peace in nature, enjoying life, relaxing.
They are alternatives to expensive forms of tourism. Outdoor activities are frequently used as a medium in education and team building. Trekking is about enjoying a great walking holiday. Treks can be day hikes, extended hikes. An example of a day trek is hiking during the day and returning at night to a lodge for a hot meal and a comfortable bed. Trekking can be more enjoyable when undertaken while being physically fit. Physical preparation for trekking includes cycling, swimming and long walks. To ensure the safest experience possible it is a good idea to have some form of experience with basic survival skills, first aid, orienteering when going for extended hikes or staying out overnight. It's expected that backpackers leave no trace while enjoying the outdoors; the activity of mountain biking involves steering a mountain cycle over rocky tracks and around boulder-strewn paths. To tackle the trails, the requirements are stamina and a strong mountain cycle. Mountain bikes or ATBs feature a rugged fork.
Their frames are built of aluminum so they are lightweight and stiff, making them efficient to ride. Many styles of mountain biking are practiced, including all mountain, trials, dirt jumping, trail riding, cross country; the latter two are the most common. Balance, core strength, endurance are all physical traits that are required to go mountain biking. Riders need bike handling skills and the ability to make basic repairs to their bikes. Advanced mountain bikers attempt technical descents as well as some of the more intense styles of mountain biking, such as down hilling and free riding. Canyoning is an activity which involves climbing, descending and trekking through canyons; the sport involves both caving and climbing techniques. When people mention canyoning they are referring to descents that involve rope work, down-climbing, or jumps that are technical in nature. Canyoning is done in remote and rugged settings and requires navigational, route-finding and other wilderness skills. University outdoor recreation programs are becoming more popular in the United States.
Universities offer indoor rock climbing walls, equipment rental, ropes courses and trip programming. A few universities give degrees in adventure recreation, which aims to teach graduates how to run businesses in the field of adventure recreation. Along with hands-on training on activities included in adventure recreation, basic courses needed for any business, such as accounting, are required to obtain a degree; the UK house of commons' Education and Skills Committee supports outdoor education. The committee encourages fieldwork projects since it helps in the development of ‘soft’ skills and social skills in hard to reach children; these activities can take place on school trips, on visits in the local community or on the school grounds. An outdoor enthusiast is a gender-neutral term for a person; the terms outdoorsman and woodsman have been used to describe someone with an affinity for the outdoors. Some famous outdoor enthusiasts include U. S. president Teddy Roosevelt, Robert Baden-Powell, Ernest Hemingway, Ray Mears, Bear Grylls, Doug Peacock, Richard Wiese, Kenneth "Speedy" Raulerso
Incandescent light bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light. The filament is protected from oxidation with a glass or fused quartz bulb, filled with inert gas or a vacuum. In a halogen lamp, filament evaporation is slowed by a chemical process that redeposits metal vapor onto the filament, thereby extending its life; the light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, work well on either alternating current or direct current; as a result, the incandescent bulb is used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, flashlights, for decorative and advertising lighting.
Incandescent bulbs are much less efficient than other types of electric lighting. The remaining energy is converted into heat; the luminous efficacy of a typical incandescent bulb for 120 V operation is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps. Some applications of the incandescent bulb deliberately use the heat generated by the filament; such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, the Easy-Bake Oven toy. Incandescent bulbs have short lifetimes compared with other types of lighting. Incandescent bulbs have been replaced in many applications by other types of electric light, such as fluorescent lamps, compact fluorescent lamps, cold cathode fluorescent lamps, high-intensity discharge lamps, light-emitting diode lamps; some jurisdictions, such as the European Union, China and United States, are in the process of phasing out the use of incandescent light bulbs while others, including Colombia, Cuba and Brazil, have prohibited them already.
In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance that made power distribution from a centralized source economically viable. Historian Thomas Hughes has attributed Edison's success to his development of an entire, integrated system of electric lighting; the lamp was a small component in his system of electric lighting, no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, the parallel-distribution system. Other inventors with generators and incandescent lamps, with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting.
In 1761 Ebenezer Kinnersley demonstrated heating a wire to incandescence. In 1802, Humphry Davy used what he described as "a battery of immense size", consisting of 2,000 cells housed in the basement of the Royal Institution of Great Britain, to create an incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an high melting point, it was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Over the first three-quarters of the 19th century, many experimenters worked with various combinations of platinum or iridium wires, carbon rods, evacuated or semi-evacuated enclosures. Many of these devices were demonstrated and some were patented. In 1835, James Bowman Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland, he stated that he could "read a book at a distance of one and a half feet". Lindsay, a lecturer at the Watt Institution in Dundee, Scotland, at the time, had developed a light, not combustible, created no smoke or smell and was less expensive to produce than Davy's platinum-dependent bulb.
However, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented, although he is credited in Challoner et al. with being the inventor of the "Incandescent Light Bulb". In 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament. In 1840, British scientist Warren de la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it; the design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although a workable design, the cost of the platinum made it impractical for commercial use. In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using platinum wires contained within a vacuum
A light-emitting diode is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons; this effect is called electroluminescence. The color of the light is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics; the first visible-light LEDs were of low intensity and limited to red. Modern LEDs are available across the visible and infrared wavelengths, with high light output. Early LEDs were used as indicator lamps, replacing small incandescent bulbs, in seven-segment displays. Recent developments have produced white-light LEDs suitable for room lighting.
LEDs have led to new displays and sensors, while their high switching rates are useful in advanced communications technology. LEDs have many advantages over incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, faster switching. Light-emitting diodes are used in applications as diverse as aviation lighting, automotive headlamps, general lighting, traffic signals, camera flashes, lighted wallpaper and medical devices. Unlike a laser, the color of light emitted from an LED is neither coherent nor monochromatic, but the spectrum is narrow with respect to human vision, functionally monochromatic. Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat's-whisker detector. Russian inventor Oleg Losev reported creation of the first LED in 1927, his research was distributed in Soviet and British scientific journals, but no practical use was made of the discovery for several decades.
In 1936, Georges Destriau observed that electroluminescence could be produced when zinc sulphide powder is suspended in an insulator and an alternating electrical field is applied to it. In his publications, Destriau referred to luminescence as Losev-Light. Destriau worked in the laboratories of Madame Marie Curie an early pioneer in the field of luminescence with research on radium. Hungarian Zoltán Bay together with György Szigeti pre-empted led lighting in Hungary in 1939 by patented a lighting device based on SiC, with an option on boron carbide, that emmitted white, yellowish white, or greenish white depending on impurities present. Kurt Lehovec, Carl Accardo, Edward Jamgochian explained these first light-emitting diodes in 1951 using an apparatus employing SiC crystals with a current source of battery or pulse generator and with a comparison to a variant, crystal in 1953. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide and other semiconductor alloys in 1955.
Braunstein observed infrared emission generated by simple diode structures using gallium antimonide, GaAs, indium phosphide, silicon-germanium alloys at room temperature and at 77 kelvins. In 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance; as noted by Kroemer Braunstein "…had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away; this signal was played back by a loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup." This setup presaged the use of LEDs for optical communication applications. In September 1961, while working at Texas Instruments in Dallas, James R. Biard and Gary Pittman discovered near-infrared light emission from a tunnel diode they had constructed on a GaAs substrate. By October 1961, they had demonstrated efficient light emission and signal coupling between a GaAs p-n junction light emitter and an electrically isolated semiconductor photodetector.
On August 8, 1962, Biard and Pittman filed a patent titled "Semiconductor Radiant Diode" based on their findings, which described a zinc-diffused p–n junction LED with a spaced cathode contact to allow for efficient emission of infrared light under forward bias. After establishing the priority of their work based on engineering notebooks predating submissions from G. E. Labs, RCA Research Labs, IBM Research Labs, Bell Labs, Lincoln Lab at MIT, the U. S. patent office issued the two inventors the patent for the GaAs infrared light-emitting diode, the first practical LED. After filing the patent, Texas Instruments began a project to manufacture infrared diodes. In October 1962, TI announced the first commercial LED product, which employed a pure GaAs crystal to emit an 890 nm light output. In October 1963, TI announced the first commercial hemispherical LED, the SNX-110; the first visible-spectrum LED was developed in 1962 by Nick Holonyak, Jr. while working at General Electric. Holonyak first reported his LED in the journal Applied Physics Letters on December 1, 1962.
M. George Craford, a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten in 1972. In 1976, T. P. Pearsall created the first high-brightness, high-efficiency LEDs for optical fiber telecommunicat
Mining is the extraction of valuable minerals or other geological materials from the earth from an ore body, vein, reef or placer deposit. These deposits form a mineralized package, of economic interest to the miner. Ores recovered by mining include metals, oil shale, limestone, dimension stone, rock salt, potash and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or water. Mining of stones and metal has been a human activity since pre-historic times. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, final reclamation of the land after the mine is closed. De Re Metallica, Georgius Agricola, 1550, Book I, Para. 1Mining operations create a negative environmental impact, both during the mining activity and after the mine has closed.
Hence, most of the world's nations have passed regulations to decrease the impact. Work safety has long been a concern as well, modern practices have improved safety in mines. Levels of metals recycling are low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products. Due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves. Since the beginning of civilization, people have used stone and metals found close to the Earth's surface; these were used to make early weapons. Flint mines have been found in chalk areas where seams of the stone were followed underground by shafts and galleries; the mines at Grimes Graves and Krzemionki are famous, like most other flint mines, are Neolithic in origin. Other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District; the oldest-known mine on archaeological record is the Ngwenya Mine in Swaziland, which radiocarbon dating shows to be about 43,000 years old.
At this site Paleolithic humans mined hematite to make the red pigment ochre. Mines of a similar age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons and tools. Ancient Egyptians mined malachite at Maadi. At first, Egyptians used the bright green malachite stones for ornamentations and pottery. Between 2613 and 2494 BC, large building projects required expeditions abroad to the area of Wadi Maghareh in order to secure minerals and other resources not available in Egypt itself. Quarries for turquoise and copper were found at Wadi Hammamat, Tura and various other Nubian sites on the Sinai Peninsula and at Timna. Mining in Egypt occurred in the earliest dynasties; the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt. These mines are described by the Greek author Diodorus Siculus, who mentions fire-setting as one method used to break down the hard rock holding the gold. One of the complexes is shown in one of the earliest known maps.
The miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust. Mining in Europe has a long history. Examples include the silver mines of Laurium. Although they had over 20,000 slaves working them, their technology was identical to their Bronze Age predecessors. At other mines, such as on the island of Thassos, marble was quarried by the Parians after they arrived in the 7th century BC; the marble was shipped away and was found by archaeologists to have been used in buildings including the tomb of Amphipolis. Philip II of Macedon, the father of Alexander the Great, captured the gold mines of Mount Pangeo in 357 BC to fund his military campaigns, he captured gold mines in Thrace for minting coinage producing 26 tons per year. However, it was the Romans who developed large scale mining methods the use of large volumes of water brought to the minehead by numerous aqueducts; the water was used for a variety of purposes, including removing overburden and rock debris, called hydraulic mining, as well as washing comminuted, or crushed and driving simple machinery.
The Romans used hydraulic mining methods on a large scale to prospect for the veins of ore a now-obsolete form of mining known as hushing. They built numerous aqueducts to supply water to the minehead. There, the water stored in large tanks; when a full tank was opened, the flood of water sluiced away the overburden to expose the bedrock underneath and any gold veins. The rock was worked upon by fire-setting to heat the rock, which would be quenched with a stream of water; the resulting thermal shock cracked the rock, enabling it to be removed by further streams of water from the overhead tanks. The Roman miners used similar methods to work cassiterite deposits in Cornwall and lead ore in the Pennines; the methods had been developed by the Romans in Spain in 25 AD to exploit large alluvial gold deposits, the largest site being at Las Medulas, where seven long aqueducts tapped local rivers and sluiced the deposits. Spain was one of the most important mining regions, but all regions of the Roman Empire were exploited.
In Great Britain the natives had mined minerals for millennia, but after the Roman conquest, the scale of the operations increased as the Romans needed Britannia's resources gold, silver
Climbing is the activity of using one's hands, feet, or any other part of the body to ascend a steep object. It is done for locomotion and competition, in trades that rely on it, in emergency rescue and military operations, it is done indoors and out, on man-made structures. Guides, such as professional mountain guides, have been an essential element of pursuing the sport in the natural environment, remain so today. Climbing activities include: Bouldering: Ascending boulders or small outcrops with climbing shoes and a chalk bag or bucket. Instead of using a safety rope from above, injury is avoided using a crash pad and a human spotter Buildering: Ascending the exterior skeletons of buildings without protective equipment. Canyoneering: Climbing along canyons for sport or recreation. Chalk climbing: Ascending chalk cliffs uses some of the same techniques as ice climbing. Competition climbing: A formal, competitive sport of recent origins practiced on artificial walls that resemble natural formations.
The International Federation of Sport Climbing is the official organization governing competition rock climbing worldwide and is recognized by the IOC and GAISF and is a member of the International World Games Association. The UIAA is the official organization governing competition ice climbing worldwide. Competition climbing has three major disciplines: Lead and Speed. Free Climbing: a form of rock climbing in which the climber uses climbing equipment such as ropes and other means of climbing protection, but only to protect against injury during falls and not to assist progress. Ice climbing: Ascending ice or hard snow formations using special equipment ice axes and crampons. Techniques of protecting the climber are similar to those of rock climbing, with protective devices adapted to frozen conditions. Indoor climbing: Top roping, lead climbing, bouldering artificial walls with bolted holds in a climbing gym. Ladder climbing: Climbing ladders for exercise; this may involve climbing up and down the underside of a ladder, or along a horizontally aligned ladder or'monkey bars'.
The ladder may be climbed going backwards, or sideways. Lumberjack tree-trimming and competitive tree-trunk or pole climbing for speed using spikes and belts. Mallakhamba: A traditional Indian sport which combines climbing a pole or rope with the performance of aerial Yoga and gymnastics. Mountaineering: Ascending mountains for sport or recreation, it involves rock and/or ice climbing. Pole climbing: Climbing poles and masts without equipment. Rock climbing: Ascending rock formations using climbing shoes and a chalk bag. Equipment such as ropes, nuts and camming devices are employed, either as a safeguard or for artificial aid. Rope access: Industrial climbing abseiling, as an alternative to scaffolding for short works on exposed structures. Rope climbing: Climbing a short, thick rope for speed. Not to be confused with roped climbing, as in rock or ice climbing. Scrambling which includes easy rock climbing, is considered part of hillwalking. Sport climbing is a form of rock climbing that relies on permanent anchors fixed to the rock, bolts, for protection.
Top roping: Ascending a rock climbing route protected by a rope anchored at the top and protected by a belayer below Traditional climbing is a form of climbing without fixed anchors and bolts. Climbers place removable protection such as camming devices and other passive and active protection that holds the rope to the rock in the event of a fall and/or when weighted by a climber. Solo climbing: Solo climbing or soloing is a style of climbing in which the climber climbs alone, without somebody belaying them; when free soloing, an error is fatal as no belay systems are being used. Soloing can be self-belayed, hence minimizing the risks. Tree climbing: Recreationally ascending trees using ropes and other protective equipment. A tower climber is a professional who climbs broadcasting or telecommunication towers or masts for maintenance or repair. Rock and tree climbing all utilize ropes for safety or aid. Pole climbing and rope climbing were among the first exercises to be included in the origins of modern gymnastics in the late 18th century and early 19th century.
Aid climbing Clean climbing Climbing clubs Climbing wall Climbing equipment Climbing organisations Fall factor List of climbers – notable rock and ice climbers List of climbing topics Glossary of climbing terms Glossary of knots common in climbing Outdoor education Outdoor activity Rock climbing Running belay Parkour Scrambling Solo climbing Speed climbing Climbing at Curlie
A hard hat is a type of helmet predominantly used in workplace environments such as industrial or construction sites to protect the head from injury due to falling objects, impact with other objects, debris and electric shock. Suspension bands inside the helmet spread the helmet's weight and the force of any impact over the top of the head. A suspension provides space of 30 mm between the helmet's shell and the wearer's head, so that if an object strikes the shell, the impact is less to be transmitted directly to the skull; some helmet shells have a mid-line reinforcement ridge to improve impact resistance. The rock climbing helmet fulfills a similar role in a different context and has a similar design. A bump cap is a lightweight hard hat using padding and a chin strap. Bump caps are used where there is a possibility of scraping or bumping one's head on equipment or structure projections but are not sufficient to absorb large impacts, such as that from a tool dropped from several stories. In the early years of the shipbuilding industry, workers covered their hats with pitch, set them in the sun to cure, a common practice for dock workers in constant danger of being hit on the head by objects dropped from ship decks.
Management professor Peter Drucker credited writer Franz Kafka with developing the first civilian hard hat while employed at the Worker's Accident Insurance Institute for the Kingdom of Bohemia, but this information is not supported by any document from his employer. In the United States, the E. D. Bullard Company was a mining equipment firm in California created by Edward Dickinson Bullard in 1898, a veteran of the industrial safety business for 20 years; the company sold protective hats made of leather. His son, E. W. Bullard, returned home from World War I with a steel helmet that provided him with ideas to improve industrial safety. In 1919 Bullard patented a "hard-boiled hat" made of steamed canvas and black paint; that same year, the U. S. Navy commissioned Bullard to create a shipyard protective cap that began the widespread use of hard hats. Not long after, Bullard developed an internal suspension to provide a more effective hat; these early designs bore a resemblance to the military M1917 "Brodie" helmet that served as their inspiration.
On the Hoover Dam project in 1931, hard hat use was mandated by Inc.. In 1933, construction began on the Golden Gate Bridge in San Francisco California. Construction workers were required to wear hard hats, by order of Joseph Strauss, project chief engineer. Strauss strove to create a safe workplace. Strauss asked Bullard to create a hard hat to protect workers who performed sandblasting. Bullard produced a design that covered the worker's face, provided a window for vision and a supply of fresh air via a hose connected to an air compressor. In those times many workmen's safety helmets were made of steel. Aluminum became a standard for hard hats except for electrical applications. MSA introduced the new plastic Skullgard Helmet in 1930 for the metals industry to withstand radiant heat loads of up to 350 °F. New plastic Bakelite was used to provide protection rigid enough to withstand hard sudden impacts within a high-heat environment but still be light enough for practical use; the machinery of the times required.
Bakelite resin compounded with wire screen and linen, the Skullgard Helmet is still manufactured. MSA produced a low-crown version for coal miners known as Comfo-Cap Headgear. Fiberglass came into use in the 1940s. Thermoplastics took over in the 1950s, as they are easy to mold and shape with heat and cost less to manufacture. In 1952, MSA offered the Shockgard Helmet to protect electrical linemen from electrical shock of up to 10,000 volts. In 1961, MSA released the first polycarbonate hard hat. 1962 brought the V-Gard Helmet, which today is the most used hardhat in the United States. Today, most hard hats are made from high-density polyethylene or advanced engineering resins, such as Ultem. In 1997 ANSI allowed the development of a ventilated hard hat. Accessories such as face shields, sun visors and perspiration-absorbing lining cloths could be used; because hard hats are intended to protect the wearer's head from impacts, hats are made from durable materials from metal fiberglass, most-commonly rigid plastic.
Some contemporary cap-style hard hats feature a rolled edge that acts as a rain gutter to channel rainwater to the front, allowing water to drain off the bill, instead of running down the wearer's neck. A cowboy hard hat is a hard hat resembling a wide brimmed cowboy hat, although some organizations disallow their use. Organizations issuing hard hats include their names and/or logos on the front of each hard hat. Hard hats may be fitted with: A visor: As in a welding helmet, or A safety visor. An extra-wide brim attachment for additional shade. Ear protectors. Mirrors for increased rear field-of-view. A small device, used to mount a headlamp or flashlight to a hard hat; the mounting device frees hands to continue working rather than having to hold a flashlight. A chinstrap to keep the helmet from falling off. Thick insulating side pads to keep sides of the head warm. Examples are seen in Ice Road Truckers. Silicone bands stretched around the brim for Hi Viz night retro-reflectivity. Hard hat colors can signify different roles on construction sites