Why are runway lights white, taxiway lights blue and airport lights rotating green and white beacon lights?

Why are runway lights white, taxiway lights blue and airport lights rotating green and white beacon lights?

PROF WAQAR HUSSAIN

 

           

A runway is rectangular area on land usually paved for the landing and take-off of air craft. Runway lights are white because white is the brightest colour and no colour is filtered out of white light. Thus enables pilot to see runway clearly even in bad weather.

            

       A taxiway is a usually paved path on an airport connecting runways with ramps, hangers, terminals and other facilities. Taxiway lights are blue as red is commonly used for warning colour and green is sometimes used to indicate direction. So, blue lights were only available for taxiway and were also not distracting.

          

      Airports have rotating beacon lights flashing green and white to indicate civilian air port. These beacon lights are visible from a far distance before the air port is recognizable.

           To facilitate the pilot at night, green threshold lights line the runway edges. Red light marks the end of runway. Blue lights run alongside taxiways, while runways have white or yellow lights marking their edges. All these markings and lights facilitate the pilot and ensure safety of landing and take-off.

Why are fog lights yellow?

Why are fog lights yellow?

PROF WAQAR HUSSAIN

   It is matter of scattering of yellow light by fog droplets. Everybody knows that shorter wavelengths of light (violet, indigo, blue) experience greater scattering than the longer wavelength of light (red, orange, yellow). Greater is the scattering; lesser is the penetration of light in fog and weaker is the vision. So, to get greater penetration of light in fog, one should use longer 

wavelength possible. Red has the longest wavelength but its use is not suitable because it is used in stop lights. Ultimately, one goes for second option i.e. Yellow. So, yellow light undergoes least scattering in fog and thus have greater penetration so increases visibility. It is the reason why fog lights are yellow!

            Many believe that this explanation is flawed for many reasons. First, fog droplet is not so small to scatter the light. 

So scattering of light by fog is independent of wavelength. Second, to get yellow light, one needs a filter which is placed on white headlights. In doing so one gets less transmitted light so the goal of getting great penetration goes to gutter.

          Third, probably fog light came into vogue with idea of signalling to other drivers that visibility is poor and greater caution is required.

          Fourth, lamp designers might have thought that yellow light had greater penetration power. So, they started making yellow fog lights. Once it came into practice, now it is continuing because of tradition.

      Fifth, European ECE regulation 48 currently requires new vehicles to be equipped with head lamps emitting white light. However, yellow head lamps are also permitted throughout Europe and in many other countries like Japan, New Zealand, etc.

        Sixth, if yellow lights are useful then why most of cars in Europe and USA are using white fog lamps.

              In spite of above discussion, I feel use of yellow lights reduce number of accidents because yellow lights sends a warning and caution message. So drivers become more attentive and put extra strain on their sight to have greater visibility, reduce speed and make greater use of horn. As a result, many accidents are avoided. However, there is another advantage of yellow lights that they neutralizes the effect of shorter blue, violet lights which create difficulty for human visual system to work properly and also cause dazzling and glaring effect in fog. So, keep on using yellow till suitable light is not available.

Why are zebra crossings white and black?

Why are zebra crossings white and black? 

PROF WAQAR HUSSAIN

   

Roads are made from black tar and the easiest way to make a patch visible was to draw white bands on the black road that can be seen easily during the day and night. This patch having black and white bands had resemblance with white and black strips of animal zebra so it came to be known as zebra crossing. Otherwise, its original name was Pedestrian Crossing. Now with the advancement of technology, people are using yellow in some places.

         The reason behind the white or black lining of zebra crossing is the visibility at day and night and also the convenience of just painting a white band on the already black road.

Why not, examiners (or teachers) should use other colour for marking!

Why not, examiners (or teachers) should use other colour for marking!

PROF WAQAR HUSSAIN

        Studies have suggested that the red colour is associated with negativity. Report says that red pen correction cause emotional distress in students. Study revealed that students think; they have been assessed more harshly if checked with red ink compared to more neutral colours like green or blue.

       In 2008, hundreds of school banned teachers from using red ink to check work because they considered it ‘confrontational’ and ‘threatening’.

         The colour issue carry no weight as red marking is more visible and also contains message of warning, prohibition, caution, anger, embarrassment, displeasure, to be careful in future- all are mandatory advices to train and groom a student. On the other hand, red written; tick mark, well-done, good, excellent, A+, carry encouragement, delight, achievement, happiness and pride.

               Another point should be kept in mind that it is the conditioning of red colour with “assessment” and “marking”, if pen of other colour is used regularly, same conditioning will emerge with that colour, carrying same level of harassment, distress and threat. So, the visibility factor must be kept in mind that is the hallmark of red ink only. 

Why examiners (or teachers) use red ink to check homework or examination papers?

Why examiners (or teachers) use red ink to check homework or examination papers?

PROF WAQAR HUSSAIN

            

          It is reported to be started in the 1700s by clerks and accountants correcting ledgers using red ink in their quills, and then teachers adopted this practice. The reason behind using red ink was to see teacher’s comment easily on the page of student’s writing as student write in blue or black. And red coloured remarks or markings get prominence. 

Why mourning dress is white in Europe?

Why mourning dress is white in Europe?

PROF WAQAR HUSSAIN

      

          For medieval European queens, white was the mourning dress. Funeral carried out for Leo V, King of Armenia, was in white. This royal tradition stayed alive in Spain till the end of 15^th century.
       Queen Fabiola revived the tradition of white dress in 1993 on the death of her husband King Baudouin I of Belgium. In 2004, Queen Juliana of the Netherland died and her four daughters wore white dresses at her funeral.

        It was the custom of the Queen of France to wear white veils for mourning; this is the origin of the white mourning wardrobe created by Norman Hartnell for a later Queen Elizabeth in 1938. She was required to make a state visit to France while in mourning for her mother.
     No convincing history and reason of white mourning dress is available. However, it is proved that white remained mourning dress in many parts of Europe and in many eras. The main reason quoted for white mourning as it is the colour of purity, piety and piousness. Its simplicity conveys the message of gloom. Coloured clothes depict happiness.

Why mourning dress is black in Europe?

Why mourning dress is black in Europe?

PROF WAQAR HUSSAIN

   
      The custom of wearing black dress for mourning dates back to the Roman Empire when the toga pulla made of dark coloured wool was worn during mourning. However, it became significant practice during Victorian age.


            

        Alexandrina Victoria was the monarch of the United Kingdom from 1837 to 1876.She was also Empress of India. She reigned for 63 year and is the longest reigning monarch and the longest reigning queen regnant in world history. Her husband Albert died in 1861 due to typhoid fever. His demise devastated Victoria and entered into state of mourning and wore black for the rest of his life. She avoided from public appearance and rarely entered in London. Due to her seclusion, she used to be called “Widow of Windsor.” This is how, Victoria set an example and it became customary and almost mandatory for bereaved families to undergo set of rituals to observe mourning of their deceased ones. The

rituals included wearing of mourning clothes, having expensive funeral, cutting off social relation for a certain period of time, and building a sophisticated monument on the grave, etc. The wearing of mourning dress was family’s manifestation of their grief. Even manuals were published to give guidance to general masses about death rituals.  Mourning etiquettes were laid down to be followed. For example, if your second cousin died and you wanted to know what sort of mourning clothes you should wear and for how long. All these instructions and guidance were recorded in The Queen or Cassell’s or other manuals. For deepest mourning; clothes were to be black, symbolic of spiritual darkness. This is how mourning dress was classified black. For happiness of marriage Victoria chose white colour and for grief she went for an opposite of white; that is black.Shakespeare said: “We mourn in black”

Why prisoner uses white and black stripe uniform?

Why prisoner uses white and black stripe uniform?

PROF WAQAR HUSSAIN

The origin of the black-and-white-striped prison uniform started in New York in the 1820s.  When Auburn Prism System was introduced demanding prisoners to be silent, walk in lockstep and wore white and black uniform with horizontal stripes that symbolize bars of prison. It made the prisoner easily identifiable and if any one escaped, the public could easily differentiate them from the non-criminals. The white and black striped uniform is quickly recognizable due to contrast of colours which are even visible at night due to white band. Prism authorities thus blessed with an Argus eye and could easily watch their activities; both inside and outside of cells. It lessened the chances of escape and scuffles.

       Striped prison uniforms, commonly used in the 19th century, were abolished in the United States early in the 20th century because people started thinking differently about prisons and punishment. Concept and attitude about prisoners shifted from punishment to concept of rehabilitation with growth of non-violent working class offender. So, striped uniform labeled it as “badge of shame” was replaced with orange or yellow jumpsuits. This uniform made escape more difficult, as it was impossible for an escaped prisoner to avoid identification and recapture apart from erasing the allegation badge of shame.

              In recent years, though, the striped prison uniform has been making a comeback as more prisons are abandoning the orange jumpsuit. Again people are thinking to use uniforms as a measure of punishment and are reverting to stripes and harsh conditions for inmates, including pink underpants for male charges. Reversals to striped uniforms have made a huge comeback for a variety of reasons, such as mistaking innocent jumpsuit workers and some others as inmates. In some countries, false reporting of people in similar clothing has become a problem. That is why; many are switched back to using striped uniforms.

Why colours are thrown on people in Holi Festival of Hindu?

Why colours are thrown on people in Holi Festival of Hindu?

PROF WAQAR HUSSAIN

          

Holi is a fun-filled spring festival celebrated on the last full moon day in the month of Phalguna Purnima (Full Moon). The festival date changes every year, per the Hindu calendar, but usually comes in March or sometimes in February. Holi is a time when humans and nature shake off the gloom of winter and rejoice in the colours of spring. It is primarily observed in India, Nepal, and other regions of the world having considerable Hindus populations. It is known as the ‘Festival of Colours’ and is celebrated in different 

ways in different regions of India. But we are interested in the colour sprinkling event! It starts the next day, and continues for a full five days, the festival takes a colourful twist when dry coloured powders and coloured water are thrown on the faces of family, friends, and even strangers.   Tradition quoted by Hindu is that with the change of the seasons, it is easy to catch a cold or virus brought on by the weather, so colourful medicinal herbs were used as precaution and to safeguard against anticipated diseases. In the beginning, coloured powder were made up of ground-up neem( Azadirachta indica) leaves(green colour), turmeric root/haldi/  the root or rootstock of the Curcuma longa. (yellow colour) and the mineral kum-kum/sindoor/vermilion/ Chemically red lead(red colour).All the ingredients were used dry and often mixed with water and splashed on others. Apart from fun festival, the sprinkling of colours during Holi once had medicinal significance. Neem is insecticidal; Turmeric is germicidal and anti-inflammatory; kum kum is natural remedy for hyperpigmentation. Keeping in mind the Ayurvedic traditions of India in mind, it appear that colour throwing might have started in health perspective.

            Today, most of the coloured dyes thrown during Holi are synthetic that is in sharp contrast to the original tradition. So, instead of countering diseased, these artificial colours may harm one's health. A study was conducted in 2001which disclosed that many of the dyes used during Holi were toxic and carried health risks; two of the colours, including red -- one of the most predominate colors -- were found to be made of carcinogenic chemicals.  Traditional sindoor was prepared from  turmeric and alum or lime , or from other herbals. These are not poisonous. Modern sindoor mainly uses vermilion; an orange-red pigment and is purified and powdered form of cinnabar (HgS) containing mercury sulfide. The compounds of mercury are toxic. Sometimes, red lead (triplumbic tetra-oxide Pb₃O₄- minium) is added to sindoor. Red lead is toxic and proved carcinogenic for experimented animals; however its carcinogenicity to humans has not yet proved.

Why do cooks wear white uniform?

 Why do cooks wear white uniform?

PROF WAQAR HUSSAIN

The white jacket is the most popular chef’s clothing in the world. There are some factors behind the use of white uniform. First, white colour symbolized cleanliness. Psychologically, everyone likes to have food prepared by a clean and healthy person and white uniform gives impression that the food preparer is neat and clean and ultimately the food prepared is also clean one. White convinces the consumer about clean, spotless, germ free, etc nature of food and above all the white cap ensures no falling of hair in food which often spoil the meal when appear in one’s food.

            Second, the other reason is chef coat serve the purpose of safety. The long, thick sleeves protect the chef from burns on the arms and the double breasting on the front protects from hot pans and sauces that may splash up. The knot buttons on the front do not melt unlike normal plastic buttons which keeps from having foreign objects falling into the food. Also, these buttons are come off quickly in case of an emergency where the coat must be removed quickly.

              Third, white is the most reflective colour, so a white jacket repels heat instead of absorbing it. Kitchens are hot places and heavy white cotton uniform insulates the body from the searing heat of stoves, hearth and ovens.

               Cook feels much cooler in white than in dark colour --and much safe in long sleeve --and much protected double breast –and much secured in white cap--and much easier in cotton which is not only soothing but also absorbs obnoxious splashing liquids. 

 Why Navy Uniforms are White?

PROF WAQAR HUSSAIN

         There a multiple reasons behind using white uniform. First, in ancient days, seafarers traveled to different countries to explore the world. They used to wear to give message of peace. As we all know, white colour symbolizes peace since ages. Second, white colour is great reflector of heat and thus keeps away the wrath of sun and person remains cool. Generally, dark coloured clothes absorb more heat.

Third, in sea voyage, health and hygiene have high priority and sickness mean silliness, stupidity and even sin as your whole world is confined on the few yards of deck with petty, paltry resources. So, white uniform help to achieve the goal of remaining hale and hearty. White not only reflects all radiations but also reflects any sign of dirt, faintest stain and even a tiny spot. So, cleanliness is highly ensured thus good health is guaranteed.  

Fourth, since older times, cotton was the widely used material for making clothes which is of white colour. Cloth of other material like silk, wool, etc were not only costly but also lacked the versatility that cotton had. Cotton clothing is environment friendly neither thick nor thin, comfortable for the body and easy to be cleaned. Navy is also the oldest global profession. So, there is chance that navy might have adopted white cotton uniform keeping in view the rate, availability and range of qualities of cotton. The process of dyeing the clothes was evolved later.

Fifth, in dark white uniform is easily identifiable and in light it can be seen from a distance in the background of Prussian blue colour of the sea. Easy detection might be reason behind its selection. Sea journeys were often dangerous, dreadful and disastrous in cruelty of weather, sea pirate, tycoons, etc. and sending SOS (save our soul) signals were a routine phenomenon. So, easily detectable and noticeable white uniform helped in rescue efforts.

Why does the beast charge at the sight of red?

PROF WAQAR HUSSAIN

 

          Bullfighting didn’t originate in Spain as many people think today. It is probably for the reason of too much attachment of the country with bullfighting. The sport got birth in ancient Mesopotamia and the areas around the Mediterranean. Greece and Rome got into the act not long after, and both often practice sacrificing their animal.

 

           In bullfighting, an angry, irritated and annoyed bull charges at a matador’s small red cape, the muleta.  Why does the beast charge at the sight of red?

It is a mistaken misconception; actually, bulls like all other cattle, are colour blind to red. In fact, the bull is irritated not by the muleta’s colour, but by the cape’s movement as the matador whips it around.

             In proof of above statement, a research conducted by Discovery Channel in 2007 is presented below. In the program, three live tests were shown depicting the choice of bull between colour and movement in three different experiments.

              In First experiment, three stationary flags of red, blue and white were placed in the bull’s enclosure. The bull charged on all the three flags regardless of colour.

               In Second experiment, three dummies dressed in red, blue and white were placed in the ring. The bull charged on all the three dummies irrespective of colour. Astonishingly, the bull charged the red dummy last.

                In Third experiment, three live persons were stationed in the ring; one person dressed in red stood still while two cowboys, dressed in other colour but not red, moved around the ring. The bull attacked the moving cowboys and left the immobile person wearing red clothing. Conclusion is crystal clear, bull irritated by the movement and not by the colour.

           Now the question arises, why is the muleta red? It is a concealing tactic; the small cape comes out in the last stage of the bullfight, when the bull meets its end, and its colour helps mask one of the horrible aspects of bullfighting: s of the bull's blood.

Why do cricketers wear white kit?

Why do cricketers wear white kit?

PROF WAQAR HUSSAIN

              

There are two reasons for it, firstly, cricket use to be called gentleman's game, and gentlemen use to wear clean spotless clothes as neat as a new pin, and white is a colour which high lights even slightest and dimmest spot on it. So they have to get it cleaned after every inning played to keep them clean and spotless. Sadly this conditionality of game resulted in keeping lots of poor but talented people away from this great game. Secondly, the colour of balls was red thus sight screens, umpire’s shirts and bowlers clothes must be white in order to make red ball clearly visible for batsman.

      Now a day, pattern of cricket has changed and three new forms of cricket have also come in to action: One Day International, Twenty-Twenty Match and Six Sixes. The cricketers are using colored uniforms in these formats of cricket because there are white ball in play and thus has no technical reason to be in white clothing .However in test matches, the ball is still red and uniform and other things are white as before. 

Why is it advised to wear white clothes in summer?

Why is it advised to wear white clothes in summer?

PROF WAQAR HUSSAIN

             

                   Because white clothes are good reflectors and bad absorbers of heat and hence they keep our bodies comparatively cooler than do the coloured clothes. That is why the inhabitants of hotter countries usually wear white dresses. It is also one of the reasons behind men using more of white clothes than women because men generally work outside the homes and thus are more exposed to the sun than women.

Why does a green leaf appear green in daylight but dark in red light?

Why does a green leaf appear green in daylight but dark in red light?

PROF WAQAR HUSSAIN

                                    GREEN LEAF             DARK LEAF

                In sunlight or white light the green leaf absorbs all constituents light colours of white except green. It means the leaf absorbs all wavelengths of colours i.e. violet, indigo, blue, yellow, orange, red but not green. Since the green light alone is reflected thus leaf appears green. Under the red light all colours including the green are absorbed in the red colour. Hence the leaf appears as dark.

Why will a white roof keep your houses cooler in summer than will a black roof?

Why will a white roof keep your houses cooler in summer than will a black roof?

PROF WAQAR HUSSAIN

        White colour is great reflector of radiations and does not absorb any radiation at all. Thus, White colour repels heat rays. Therefore white roof absorbs comparatively less heat and reflects the heat outward. On the contrary, the black roof absorbs the heat and does not reflect it. Hence, the house with white roof is cooler.

Why brides wear white dress on weddings in Europe?

Why brides wear white dress on weddings in Europe?

PROF WAQAR HUSSAIN

                White wedding dress came into vogue during reign of Queen Victoria in 1800s. It was introduced as symbol of wealth. It was preferred to show the world that the bride’s family was a wealthy. Royal bride before Victoria used to wear heavy brocaded gown embroidered with white and silver thread.

               Before Victoria, the brides used to wear almost any colour, except black which was attached with mourning, and red associated with prostitutes. Brides who wanted to wear a symbol of their purity wore blue.

           The tradition of wearing white bridal dress gained popularity on February 10, 1840; when Queen Victoria of England married her cousin Albert of Saxe-Coberg. She wore off-white, silk-satin gown incorporated with some lace that she owned. Selecting to wear the creamy-hued confection was a far-reaching decision at the time as silver was go-to color for royal wedding dresses, and blue and yellow bridal dress were also popular — but certainly not white. So, at that time, a white wedding dress was exceptionally uncommon, and it was not a sign of purity, but a sign of wealth.  Only very rich women could afford a dress that could never be worn again as cleaning a white dress was not so easy on those days and cotton was a costly commodity. 

            

          Later on, many women copied the queen's style for their weddings proving saying: “masses follow the footstep of their rulers”. In mid of 20th century, white wedding dress got popularity as the pictures, videos and accounts of  weddings of the world's wealthiest and  famous celebrities came to public knowledge. This trend then spread like a jungle fire and became a common practice.

            Many consider white dress as a symbol of purity, piety and piousness but in reality; it was more a symbol of vanity than virginity. Many say that the virginal connotations for white wedding gowns are pure magazine editorial fiction. 

             Why not! People dare to drift away from the history and drag in the wide range of symbolisms of white colour to pay an unmatchable gift to the wedding women and wish her all the blessings attributed with white hue. White dress denote inherent positivity, purity, virginity, innocence, light, goodness, heaven, safety, brilliance, illumination, understanding, cleanliness, faith, a successful beginnings, spirituality, possibility, humility, sincerity, protection, softness, and perfection. May these symbolisms transform into reality for the nuptial bride; entering into a new avenue of her life!