Blackboard
 NASA scientistHomer E. Newell Jr.explaining principles of altitude, pressure, and temperature, c. 1973 | |
| Other names | Chalkboard, writing-board |
|---|---|
| Uses | Reusable writing surface on which text or drawings are made |
Ablackboardor achalkboardis a reusablewritingsurface on which text or drawings are made with sticks ofcalcium sulphateorcalcium carbonate,known, when used for this purpose, aschalk.Blackboards were originally made of smooth, thin sheets of black or dark greyslatestone.
Design
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A blackboard can simply be a board painted with a darkmattepaint(usually black, occasionally dark green).[1]Matte black plastic sign material (known asclosed-cell PVC foamboard) is also used to create customchalkboard art.[2]Blackboards on anA-frameare used by restaurants and bars to advertise daily specials.[3]Adhesive chalkboard surface is also available in stores as rolls of textured black plastic shelf covering, which is applied to the desired wall, door or other surface.
A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade blackboards are made ofporcelain-enameled steel(black, green, blue or sometimes other colours).Porcelainis very hard wearing, and blackboards made of porcelain usually last 10–20 years in intensive use.[4]
Lecture theatresmay contain a number of blackboards in a grid arrangement.[5]The lecturer then moves boards into reach for writing and then moves them out of reach, allowing a large amount of material to be shown simultaneously.
The chalk marks can be easily wiped off with a damp cloth, a sponge or a specialblackboard eraserusually consisting of a block of wood covered by a felt pad. However, chalk marks made on some types of wet blackboard can be difficult to remove. Blackboard manufacturers often advise that a new or newly resurfaced blackboard be completely covered using the side of a stick of chalk and then that chalk brushed off as normal to prepare it for use.[citation needed]
Chalk sticks
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Chalk sticks are produced in white and in various colours, especially for use with blackboards. White chalk sticks are made mainly from calcium carbonate derived from mineralchalkor limestone, while coloured chalk sticks are made fromcalcium sulphatein itsdihydrateform, CaSO4·2H2O, derived fromgypsum.[6][7]Chalk sticks containingcalcium carbonatetypically contain 40–60% of CaCO3(calcite).
Advantages and disadvantages
[edit] | This sectionpossibly containsoriginal research.(October 2023) |
Advantages
[edit]- Low Maintenance:Chalk requires no special care; unlike whiteboard markers, chalk does not dry out if left uncapped.
- Cost-Efficiency:Chalk is significantly cheaper than whiteboard markers, providing a cost-effective option for extensive writing.
- Drawing Versatility:Chalk allows for the easy creation of lines with different weights and thicknesses, surpassing the capabilities of whiteboard markers.
- Quick Dashed Lines:The friction technique with chalk enables the swift creation of dashed lines, a task that might be more cumbersome with whiteboard markers.
- Odor Considerations:Chalk's mild smell contrasts with the often pungent odor of whiteboard markers, offering a more pleasant writing experience.
- Contrast and Visibility:Chalk writing generally provides better contrast than whiteboard markers, ensuring clear visibility in various lighting conditions.
- Non-Reflective Surface:Blackboards do not reflect light like whiteboards, allowing information to be viewable from all angles without glare.
- Ease of Erasure:Chalk can be easily erased, while whiteboard markings left for an extended period may require solvents for removal.
- Stain Resistance:Chalk can be easily removed from most surfaces, including clothing, in contrast to whiteboard markers that may leave permanent stains.
- Environmental Impact:Chalk is mostly biodegradable, while whiteboard markers pose challenges for plastic recycling
Disadvantages
[edit]On the other hand, chalk produces dust, the amount depending on the quality of chalk used. Some people find this uncomfortable or may beallergicto it, and according to theAmerican Academy of Allergy, Asthma and Immunology(AAAAI), there are links between chalk dust and allergy and asthma problems.[8]The dust also precludes the use of chalk in areas shared with dust-sensitive equipment such ascomputers.The writing on blackboards is difficult to read in the dark. Chalk sticks shrink through use, and are notorious for breaking in half unless inserted in awriting utensildesigned for chalk. Blackboards can suffer from ghosting. Ghosting occurs when old coloured chalk, pastels or chalkpen ink absorbs into the black finish of the board, making it impossible to remove.[9]
Thescratching of fingernails on a blackboard,as well as other pointed, especially metal objects against blackboards, produces a sound that is well known for being extremely irritating to most people.[10]According to a study run by Michael Oehler, a professor at theUniversity of Cologne,Germany, humans are "predisposed to detest" the sound of nails on a blackboard.[11]The findings of the study were presented at theAcoustical Society of Americaconference and support earlier findings from a 1986 study by Vanderbilt psychologistRandolph Blakeand two colleagues found that the sound of nails on a chalkboard annoyed people even when the high-pitch frequencies were removed. The study earned Blake a 2006Ig Nobel Prize.[12]
Etymology and history
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Thewriting slatewas in use in Indian schools as mentioned inAlberuni'sIndica(Tarikh Al-Hind), written in the early 11th century:
They use black tablets for the children in the schools, and write upon them along the long side, not the broadside, writing with a white material from the left to the right.[13]
The first classroom uses of large blackboards are difficult to date, but they were used for music education and composition in Europe as far back as the 16th century.[14]The term "blackboard" is attested in English from the mid-18th century; theOxford English Dictionaryprovides a citation from 1739, to write "with Chalk on a black-Board".[15]The first attested use of chalk on blackboard in the United States dates to September 21, 1801, in a lecture course in mathematics given byGeorge Baron.[16]James Pillanshas been credited with the invention of coloured chalk (1814); he had a recipe with ground chalk, dyes and porridge.[17]
The use of blackboards changed methods of education and testing, as found in theConic Sections Rebellionof 1830 in Yale.[18] Manufacturing of slate blackboards began by the 1840s.[4]Green porcelain enamel surface, was first used in 1930, and as this type of boards became popular, the word "chalkboard" appeared.[4]In the US green porcelain enamelled boards started to appear at schools in 1950s.[19]
Gallery
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An advertising blackboard in Taipei, Taiwan, 2019 -
Mathematics on a board, 2017 -
Teacher explaining the decimal system of weights using a blackboard,Guinea-Bissau,1974 -
An Austrian chemist with colored chalk (1970) -
A schoolboy in Seattle, WA, USA, 1961
See also
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- Blackboard bold
- Blackboard Jungle
- Chalkboard font
- Chalkboard gagfromThe Simpsons
- ChalkZone
- Conic Sections Rebellion,an 1830 student uprising when Yale students were required to draw their own diagrams on the blackboard
- Einstein's Blackboard
- Hagoromo Bungu,Japanese chalk company
- Sidewalk chalk
- Simon in the Land of Chalk Drawings
- Slate
- Tacita Dean,an artist who often uses blackboards in her work
- Whiteboard
Notes
[edit]- ^Philip, Shaju (June 30, 2014)."CPM slams use of green boards in Kerala schools".The Indian Express.RetrievedFebruary 17,2021.
- ^Downs, Stacy (June 1, 2012)."The ABCs of chalkboard paint".The Wichita Eagle.RetrievedFebruary 17,2021.
- ^Goldsworthy, Jessica (September 23, 2018)."Temporary Signage Ideas For Restaurants".squaresigns.com.RetrievedFebruary 17,2021.
- ^abcBuzbee, Lewis (2014).Blackboard: A Personal History of the Classroom.Graywolf Press. p. 45.ISBN978-1-55597-683-5– viaGoogle Books.
- ^"Film Locations: The Most Filmed College Classroom Is Inside Columbia University's Havemeyer Hall".Untapped New York.2013-06-27.Retrieved2021-03-21.
- ^"How chalk is made – material, making, used, processing, procedure, product, industry".madehow.com.RetrievedFebruary 17,2021.
- ^Corazza, M.; Zauli, S.; Pagnoni, A.; Virgili, A. (2012)."Allergic contact dermatitis caused by metals in blackboard chalk: a case report".Acta Dermato-Venereologica.92(4): 436–437.doi:10.2340/00015555-1296.PMID22367154.
- ^"Reading, Writing, and Wheezing? Not Necessarily".WebMD.September 19, 2000.RetrievedFebruary 13,2021.
- ^"What Are Chalkboards | Majisign".www.majisign.co.uk.21 November 2020.Retrieved2021-03-21.
- ^Wong, Sam (February 28, 2017)."The feeling you get when nails scratch a blackboard has a name".New Scientist(3115).RetrievedFebruary 17,2021.
- ^Siegel, Robert (November 9, 2011)."Why Nails On A Chalkboard Drives Us Crazy".NPR.RetrievedFebruary 17,2021.
- ^Frances Romero (14 June 2010)."Top 10 Most Annoying Sounds: Nails on a Chalkboard".Time.Retrieved31 May2016.
- ^Alberuni's India. An account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030.1910.
- ^Owens, Jessie Ann (1998).Composers at Work: The Craft of Musical Composition, 1450-1600.Oxford University Press.p. 82.ISBN978-0-19-512904-5– viaGoogle Books.
- ^Entry for"blackboard,n",in theOxford English Dictionary(Third ed., 2011)
- ^Stephen E. Ambrose (1 December 1999).Duty, Honour, Country: A History of West Point.JHU Press. p. 19.ISBN978-0-8018-6293-9.Retrieved14 February2013.
- ^Jo Swinnerton (30 September 2005).The History of Britain Companion.Anova Books. p. 128.ISBN978-1-86105-914-7.Retrieved14 February2013.
- ^Jackson, Allyn (2002)."Teaching Math in America: An Exhibit at the Smithsonian"(PDF).Notices of the American Mathematical Society.49(9): 1082.RetrievedFebruary 17,2021.
- ^David, Lester (April 1952)."I Found My Future in the Past".Popular Science(April 1952): 144.ISSN0161-7370– viaGoogle Books.
Further reading
[edit]- Aldrich Kidwell, Peggy; Ackerberg-Hastings, Amy; Lindsay Roberts, David (2008)."The Blackboard: An Indispensable Necessity".Tools of American Mathematics Teaching, 1800–2000.Johns Hopkins University Press.pp. 21–34.ISBN978-0-8018-8814-4– viaGoogle Books.
- Ansell, Ben W. (2010).From the Ballot to the Blackboard: The Redistributive Political Economy of Education.New York City:Cambridge University Press.ISBN978-1-107-61699-8.OCLC876849496.
- Whitney, Frederick (1909).Blackboard sketching.Milton Bradley Company– viaInternet Archive.
External links
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The dictionary definition ofblackboardat Wiktionary- The dictionary definition ofchalkboardat Wiktionary
Media related toBlackboardsat Wikimedia Commons
