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Uses. Reusable writing surface on which text or drawings are made. A blackboard or a chalkboard is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone.
Blackboard chalk manufacturers now may use mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to produce, and thus widely used in the developing world , use of carbonate-based chalk produces larger particles and thus less dust, and it is ...
Chalkboard scraping. Scraping a chalkboard (also known as a blackboard) with one's fingernails produces a sound and feeling which most people find extremely irritating. The basis of the innate reaction to the sound has been studied in the field of psychoacoustics (the branch of psychology concerned with the perception of sound and its ...
Blackboard bold is a style of writing bold symbols on a blackboard by doubling certain strokes, commonly used in mathematical lectures, and the derived style of typeface used in printed mathematical texts. The style is most commonly used to represent the number sets ( natural numbers ), ( integers ), ( rational numbers ), ( real numbers ), and ...
Sidewalk chalk is typically large and thick sticks of chalk ( calcium sulfate, gypsum, rather than calcium carbonate, rock chalk) that come in multiple colors and are mostly used for drawing on pavement or concrete sidewalks, frequently four square courts or a hopscotch boards. Blackboard chalk, typically used in educational settings, is ...
Einstein's Blackboard at the Museum of the History of Science in Oxford. Einstein's Blackboard is a blackboard [1] which physicist Albert Einstein (1879–1955) used on 16 May 1931 during his lectures while visiting the University of Oxford in England. [2] [3] The blackboard is in the collection of the Museum of the History of Science in Oxford.
Some other photographs show chalk drawings that were deliberately created to be photographed for this book. The mathematicians themselves are not depicted. [1] Many of their comments relate to their tactile pleasure in using chalk, to the semi-permanence of partially-legible erasures from chalkboards, and to the pacing the use of chalk imparts ...
1976. ( 1976) Simon in the Land of Chalk Drawings is a British-Canadian children's animated series about the adventures of a young boy named Simon, who has a magic blackboard. [1] Things that Simon draws on the chalkboard become real in the Land of Chalk Drawings, which Simon can enter by climbing over a fence near his home with a ladder.