igloo |
chisel |
top 10 words in brain distribution (in article): build people common house form refer type line popular modern |
top 10 words in brain distribution (in article): light produce type form design allow contain time common require |
top 10 words in brain distribution (not in article): state plant city wear horse fruit century time world power |
top 10 words in brain distribution (not in article): drink lamp cell wine beer water bottle key valve body |
times more probable under igloo 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under chisel (words not in the model) | |
An igloo'" (Inuit language: "iglu", Inuktitut syllabics: ᐃᒡᓗ, "house", plural: "iglooit" or "igluit", but in English commonly "igloos"), translated sometimes as snowhouse'", is the Inuit word for house or habitation, and is not restricted exclusively to snowhouses but includes traditional tents, sod houses, homes constructed of driftwood and modern buildings. Igloo as a snowhouse. When referring to a snowhouse, igloos are shelters constructed from blocks of snow, generally in the form of a dome. Although igloos are usually associated with all Inuit, they were predominantly constructed by people of Canada's Central Arctic and Greenland's Thule area. Other Inuit people tended to use snow to insulate their houses which consisted of whalebone and hides. Snow was used because the air pockets trapped in it make it an insulator. On the outside, temperatures may be as low as, but on the inside the temperature may range from to when warmed by body heat alone. Traditional types. There were three traditional types of igloos, all of different sizes and all used for different purposes. The smallest was constructed as a temporary shelter, usually only used for one or two nights. These were built and used during hunting trips, often on open sea ice. Next in size was the semi-permanent, intermediate-sized family dwelling. This was usually a single room dwelling that housed one or two families. Often there were several of these in a small area, which formed an "Inuit village". The largest of the igloos was normally built in groups of two. One of the buildings was a temporary structure built for special occasions, the other built nearby for living. These might have had up to five rooms and housed up to 20 people. A large igloo might have been constructed from several smaller igloos attached by their tunnels, giving common access to the outside. These were used to hold community feasts and traditional dances. Modifications. The Central Inuit, especially those around the Davis Strait, lined the living area with skin, which could increase the temperature within from around 2 °C (36 °F) to 10-20 °C (50-68 °F). Construction. The snow used to build an igloo must have sufficient structural strength to be cut and stacked in the appropriate manner. The best snow to use for this purpose is snow which has been blown by wind, which can serve to compact and interlock the ice crystals. The hole left in the snow where the blocks are cut from is usually used as the lower half of the shelter. Sometimes, a short tunnel is constructed at the entrance to reduce wind and heat loss when the door is opened. Due to snow's excellent insulating properties, inhabited igloos are surprisingly comfortable and warm inside. In some cases a single block of ice is inserted to allow light into the igloo. Architecturally, the igloo is unique in that it is a dome that can be raised out of independent blocks leaning on each other and polished to fit without an additional supporting structure during construction. The igloo, if correctly built, will support the weight of a person standing on the roof. Also, in the traditional Inuit igloo the heat from the kulliq (stone lamp) causes the interior to melt slightly. This melting and refreezing builds up an ice sheet and contributes to the strength of the igloo. The sleeping platform is a raised area compared to where one enters the igloo. Because warmer air rises and cooler air settles, the entrance area will act as a cold trap whereas the sleeping area will hold whatever heat is generated by a stove, lamp or body heat. In popular use. In heraldry, the igloo appears as the crest in the coat of arms of Nunavut. "Nanook of the North". The 1922 documentary "Nanook of the North" contains the oldest surviving movie footage of an Inuit constructing an igloo. In the film, Nanook (real name Allakariallak) builds a large family igloo as well as a smaller igloo for sled pups. Nanook demonstrates the use of an ivory knife to cut and trim snow block, as well as the use of clear ice for a window. His igloo was built in about one hour, and was large enough for five people. The igloo was cross-sectioned for filmmaking, so interior shots could be made. See "External links" for video footage. | A chisel'" is a tool with a characteristically shaped cutting edge (such that wood chisels have lent part of their name to a particular grind) of blade on its end, for carving or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it. In use, the chisel is forced into the material to cut the material. The driving force may be manually applied or applied using a mallet or hammer. In industrial use, a hydraulic ram or falling weight ('trip hammer') drives the chisel into the material to be cut. A "gouge", one type of chisel, is used, particularly in woodworking, woodturning and sculpture, to carve small pieces from the material. Gouges are most often used in creating concave surfaces. A gouge typically has a 'U'-shaped cross-section. Types of Chisels. Chisels have a wide variety of uses. Many types of chisels have been devised, each specially suited to its intended use. Different types of chisels may be constructed quite differently, in terms of blade width or length, as well as shape and hardness of blade. They may have wooden handles attached or may be made entirely of one piece of metal. Woodworking chisels. Woodworking chisels range from quite small hand tools for tiny details, to large chisels used remove big sections of wood, in 'roughing out' the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool, and gradually progresses to smaller tools to finish the detail. One of the largest types of chisel is the slick, used in timber frame construction and wooden shipbuilding. According to their function there are many names given to woodworking chisels, such as: Japanese woodworking chisels. The better quality Japanese wood chisels are made from laminated steel. There are different types of metals used in each chisel. The better ones are laminated by hand, over a charcoal fire. The combination of the metals makes a chisel that takes a very sharp edge, and is hard enough to maintain the edge for a long time. This technique produces a tools that have a harder edge, usually a hardness rating of Rockwell 64, compared to their western counterparts of around 62 on the Rockwell scale. There are two basic metals used in these chisels, white steel and blue steel. The names come from the color of the paper the steels are wrapped in. White and blue steel come in vary grades, that vary in carbon content. Both have low levels of impurities. White steel is a simple carbon steel. Blue steel contains alloying elements, and sacrifices some sharpness for edge retention, toughness, and corrosion resistance, although it is not stainless. Many makers are descendants of the samurai sword makers, once highly respected members of their country, until these swords were outlawed. The chisel makers often turned their attention to chisel and plane makers. Expensive sets have a decorative wood grain look to them which is actually the thin layers of steel being hammered together. The neck of the chisel can be twisted to add to the decorative look of the tool. The handles are often made from an exotic hardwood, such as ebony. The sets usually come in a wooden box, signed by the maker. Japanese chisels have hollows in the back side, the wider ones having as many as four hollows. These are intended to help in the flattening of the back of the chisels, which is the first step in sharpening a chisel. Once the back side is perfectly flat, and polished to the required degree, the front and side edges need to be addressed. A general rule is any chisel with a hoop, or metal ring at the end of the handle, is it's designed to be struck with mallet. If it does not have a hoop, it is a paring tool, designed not to be struck with another tool. Lathe tools. A lathe tool is a woodworking chisel designed to cut wood as it is spun on a lathe. These tools have longer handles for more leverage, needed to counteract the tendency of the tool to react to the downward force of the spinning wood being cut or carved. In addition, the angle and method of sharpening is different, a secondary bevel would not be ground on the tool. Woodworking chisels range from quite small hand tools for tiny details, to large chisels used remove big sections of wood, in 'roughing out' the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool, and gradually progresses to smaller tools to finish the detail. One of the largest types of chisel is the slick, used in timber frame construction and wooden shipbuilding. Metalworking chisels. Chisels used in metal work can be divided into two main categories, "hot" chisels, and "cold" chisels. A hot chisel is used to cut metal that has been heated in a forge to soften the metal. Cold chisel. A cold chisel'" is a tool made of tempered steel used for cutting 'cold' metals, meaning that they are not used in conjunction with heating torches, forges, etc. Cold chisels are used to remove waste metal when a very smooth finish is not required or when the work cannot be done easily with other tools, such as a hacksaw, file, bench shears or power tools. The name cold chisel comes from its use by blacksmiths to cut metal while it was cold as compared to other tools they used to cut hot metal. This tool is also commonly referred to by the misnomer 'coal chisel'. Because cold chisels are used to form metal, they have a less-acute angle to the sharp portion of the blade than a woodworking chisel. This gives the cutting edge greater strength at the expense of sharpness. Cold chisels come in a variety of sizes, from fine engraving tools that are tapped with very light hammers, to massive tools that are driven with sledgehammers. Cold chisels are forged to shape and hardened and tempered (to a brown colour) at the cutting edge. The head of the chisel is chamfered to slow down the formation of the mushroom shape caused by hammering and is left soft to withstand hammer blows. The are four common types of cold chisel. These are the flat chisel, the most widely known type, which is used to cut bars and rods to reduce surfaces and to cut sheet metal which is too thick or difficult to cut with snips. The cross cut chisel is used for cutting grooves and slots. The blade narrows behind the cutting edge to provide clearance. The round nose chisel is used for cutting semi-circular grooves for oil ways in bearings. The diamond point chisel is used for cleaning out corners or difficult places and pulling over centre punch marks wrongly placed for drilling. Although the vast majority of cold chisels are made of steel, a few are manufactured from beryllium copper, for use in special situations where non-sparking tools are required. Hardy chisel. A toothed stone chisel, used by stone sculptors and stonemasons A "'hardy chisel'" is a type of hot chisel with a square shank, which is held in place with the cutting edge facing upwards by placing it in an anvil's Hardy hole. The hot workpiece cut is then placed over the hardy, and struck with a hammer. The hammer drives the chisel into the hot metal, allowing it to be snapped off with a pair of tongs. Stone chisels. Stone chisels are used to carve or cut stone, bricks or concrete slabs. To cut, as opposed to carve, a brick bolster is used; this has a wide, flat blade that is tapped along the cut line to produce a groove, then hit hard in the centre to crack the stone. Sculptors use a "spoon chisel", which is bent, with the bezel (cutting edge) on both sides. To increase the force, stone chisels are often hit with club hammers, a heavier type of hammer. Masonry chisels. Masonry chisels are typically heavy, with a relatively dull head that wedges and breaks, rather than cuts. Normally used as a demolition tool, they may be mounted on a hammer drill, jack hammer, or hammered manually, usually with a heavy hammer of three pounds or more. Plugging chisel. A Plugging chisel has a tapered edge for cleaning out hardened mortar. The chisel is held with one hand and struck with a hammer. The direction of the taper in the blade determines if the chisel cuts deep or runs shallow along the joint. |