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Chalkboard Eraser
A chalkboard eraser is a special type of eraser specifically used to erase chalk markings on slating paint (used on chalkboards and slates). It is most commonly made of felt strips attached to a handle. Chalkboard erasers are typically broad and rectangular, intended to clear large areas for new content as part of a lecture or presentation. History Chalkboard erasers were invented around 1863 by John L. Hammett, who owned some stores that sold and created school products in Rhode Island and then later in Boston. Mostly slates were sold there as well as chalk and so on. At the time, rags or old cloths were used to erase and get rid of the chalk markings on slates in schools, offices, and for the most part, everywhere. Hammett created the chalkboard before the invention of the chalkboard eraser by creating ''slating paint''. Hammett then, during a presentation on his chalkboard "discovered" that wool felt strips wiped off the chalk writing better than rags. Following this discovery h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalkboard Eraser, Waldorf School, East Lexington MA
A blackboard (also known as 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 Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone. Design A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green). Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art. Blackboards on an A-frame are used by restaurants and bars to advertise daily specials. 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 of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eraser
An eraser (also known as a rubber in some Commonwealth countries, including South Africa from the material first used) is an article of stationery that is used for removing marks from paper or skin (e.g. parchment or vellum). Erasers have a rubbery consistency and come in a variety of shapes, sizes and colors. Some pencils have an eraser on one end. Less expensive erasers are made from synthetic rubber and synthetic soy-based gum, but more expensive or specialized erasers are made from vinyl, plastic, or gum-like materials. At first, erasers were invented to erase mistakes made with a pencil; later, more abrasive ink erasers were introduced. The term is also used for things that remove marks from chalkboards and whiteboards. History Before rubber erasers used today, tablets of wax were used to erase lead or charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink. Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel. Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for " blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum. Description Chalk is a fine-textured, earthy type of limestone distinguished by its light color, softness, and high porosity. It is composed mostly of tiny fragments of the calcite shells or skeletons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalkboard
A blackboard (also known as 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. Design A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green). Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art. Blackboards on an A-frame are used by restaurants and bars to advertise daily specials. 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 of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slate (writing)
A slate is a thin piece of hard flat material, historically slate stone, which is used as a medium for writing. Composition The writing slate consisted of a piece of slate, typically either 4x6 inches or 7x10 inches, encased in a wooden frame. A slate pencil was used to write on the slate board. It was made from a softer and lighter coloured stone such as shale or chalk. Usually, a piece of cloth or slate sponge was used to clean it and this was sometimes attached with a string to the bottom of the writing slate. History The exact origins of the writing slate remain unclear. References to its use can be found in the fourteenth century and evidence suggests that it was used in the sixteenth and seventeenth centuries. The central time period for the writing slate, however, "appears to begin in the later eighteenth century, when developments in sea and land transport permitted the gradual expansion of slate quarrying in Wales and the growth of a substantial slate workshop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Felt
Felt is a textile material that is produced by matting, condensing and pressing fibers together. Felt can be made of natural fibers such as wool or animal fur, or from synthetic fibers such as petroleum-based acrylic or acrylonitrile or wood pulp–based rayon. Blended fibers are also common. Natural fibre felt has special properties that allow it to be used for a wide variety of purposes. "It is fire-retardant and self-extinguishing; it dampens vibration and absorbs sound; and it can hold large amounts of fluid without feeling wet..." History Felt from wool is one of the oldest known textiles. Many cultures have legends as to the origins of felt making. Sumerian legend claims that the secret of feltmaking was discovered by Urnamman of Lagash. The story of Saint Clement and Saint Christopher relates that the men packed their sandals with wool to prevent blisters while fleeing from persecution. At the end of their journey, the movement and sweat had turned the wool into f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhode Island
Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States by population, seventh-least populous, with slightly fewer than 1.1 million residents 2020 United States census, as of 2020, but it is the List of U.S. states by population density, second-most densely populated after New Jersey. It takes its name from Aquidneck Island, the eponymous island, though most of its land area is on the mainland. Rhode Island borders Connecticut to the west; Massachusetts to the north and east; and the Atlantic Ocean to the south via Rhode Island Sound and Block Island Sound. It also shares a small maritime border with New York (state), New York. Providence, Rhode Island, Providence is its capital and most populous city. Native Americans lived around Narragansett Bay for thousands of years before English settler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boston
Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- most populous city in the country. The city boundaries encompass an area of about and a population of 675,647 as of 2020. It is the seat of Suffolk County (although the county government was disbanded on July 1, 1999). The city is the economic and cultural anchor of a substantially larger metropolitan area known as Greater Boston, a metropolitan statistical area (MSA) home to a census-estimated 4.8 million people in 2016 and ranking as the tenth-largest MSA in the country. A broader combined statistical area (CSA), generally corresponding to the commuting area and including Providence, Rhode Island, is home to approximately 8.2 million people, making it the sixth most populous in the United States. Boston is one of the oldest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wool
Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. As an animal fibre, wool consists of protein together with a small percentage of lipids. This makes it chemically quite distinct from cotton and other plant fibres, which are mainly cellulose. Characteristics Wool is produced by follicles which are small cells located in the skin. These follicles are located in the upper layer of the skin called the epidermis and push down into the second skin layer called the dermis as the wool fibers grow. Follicles can be classed as either primary or secondary follicles. Primary follicles produce three types of fiber: kemp, medullated fibers, and true wool fibers. Secondary follicles only produce true wool fibers. Medullated fibers share nearly identical characteristics to hair and are long but lack c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
School
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some schooling to very young children (typically ages 3–5). University, vocational school, college or seminary may be avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes. The papermaking process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, although the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eraser
An eraser (also known as a rubber in some Commonwealth countries, including South Africa from the material first used) is an article of stationery that is used for removing marks from paper or skin (e.g. parchment or vellum). Erasers have a rubbery consistency and come in a variety of shapes, sizes and colors. Some pencils have an eraser on one end. Less expensive erasers are made from synthetic rubber and synthetic soy-based gum, but more expensive or specialized erasers are made from vinyl, plastic, or gum-like materials. At first, erasers were invented to erase mistakes made with a pencil; later, more abrasive ink erasers were introduced. The term is also used for things that remove marks from chalkboards and whiteboards. History Before rubber erasers used today, tablets of wax were used to erase lead or charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink. Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
%2C_Western_Negev%2C_Israel.jpg "Click for more on -> Chalk")
