1.
Adventures of Huckleberry Finn
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Adventures of Huckleberry Finn is a novel by Mark Twain, first published in the United Kingdom in December 1884 and in the United States in February 1885. Commonly named among the Great American Novels, the work is among the first in major American literature to be written throughout in vernacular English and it is told in the first person by Huckleberry Huck Finn, a friend of Tom Sawyer and narrator of two other Twain novels. It is a sequel to The Adventures of Tom Sawyer. The book is noted for its description of people and places along the Mississippi River. Perennially popular with readers, Adventures of Huckleberry Finn has also been the object of study by literary critics since its publication. In order of appearance, Huckleberry Finn is a boy about thirteen or fourteen or along there years old and he has been brought up by his father, the town drunk, and has a difficult time fitting into society. Widow Douglas is the woman who has taken Huck in after he helped save her from a violent home invasion. She tries her best to civilize Huck, believing it is her Christian duty, Miss Watson is the widows sister, a tough old spinster who also lives with them. She is fairly hard on Huck, causing him to resent her a good deal, Mark Twain may have drawn inspiration for this character from several people he knew in his life. Jim is Miss Watsons physically large but mild-mannered slave, Huck becomes very close to Jim when they reunite after Jim flees Miss Watsons household to seek refuge from slavery, and Huck and Jim become fellow travelers on the Mississippi River. Tom Sawyer is Hucks best friend and peer, the character of other Twain novels. He is the best fighter and the smartest kid in town, Pap Finn, Hucks father, a brutal alcoholic drifter. He resents Huck getting any kind of education and his only genuine interest in his son involves begging or extorting money to feed his alcohol addiction. The Grangerfords, an aristocratic Kentuckian family headed by the sexagenarian Colonel Saul Grangerford, Huck becomes close friends with the youngest male of the family, Buck Grangerford, who is Hucks age. By the time Huck meets them, the Grangerfords have been engaged in a blood feud with another local family. The Duke and the King are two otherwise unnamed con artists whom Huck and Jim take aboard their raft just before the start of their Arkansas adventures, doctor Robinson is the only man who recognizes that the King and Duke are phonies when they pretend to be British. He warns the town but they ignore him, mary Jane, Joanna, and Susan Wilks are the three young nieces of their wealthy guardian, Peter Wilks, who has recently died. The duke and the try to steal the inheritance left by Peter Wilks
2.
Boat
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A boat is a watercraft of a large range of sizes designed to float, plane, work or travel on water. Small boats are found on inland waterways or in protected coastal areas. However, boats such as the whaleboat were designed for operation from a ship in an offshore environment, in naval terms, a boat is a vessel small enough to be carried aboard another vessel. Another less restrictive definition is a vessel that can be lifted out of the water, some definitions do not make a distinction in size, as bulk freighters 1,000 feet long on the Great Lakes are called oreboats. For reasons of tradition, submarines are usually referred to as boats rather than ships, regardless of their size. Ships are generally distinguished from boats based on their size, shape. Boats have a variety of shapes, sizes and construction methods due to their intended purpose. Canoe-type boats have used since prehistoric times and various versions are used throughout the world for transportation. Fishing boats vary widely in style partly to local conditions. Pleasure boats include ski boats, pontoon boats, and sailboats, house boats may be used for vacationing or long-term housing. Small boats can provide transport or convey cargo to and from large ships, lifeboats have rescue and safety functions. Boats can be powered by power, wind power and motor power. Dugouts are the oldest type of boats found by archaeologists, the earliest boats are thought to have been logboats, and the oldest boats found by archaeological excavation date from around 7, 000–10,000 years ago. The oldest recovered boat in the world is the Pesse canoe and this canoe is exhibited in the Drents Museum in Assen, Netherlands. Other very old dugout boats have also been recovered, rafts have operated for at least 8,000 years. A7, 000-year-old seagoing reed boat has been found in Kuwait, boats were used between 4000 and 3000 BC in Sumer, ancient Egypt and in the Indian Ocean. Boats played an important role in the commerce between the Indus Valley Civilization and Mesopotamia, evidence of varying models of boats has also been discovered at various Indus Valley archaeological sites. Uru craft originate in Beypore, a village in south Calicut, Kerala and this type of mammoth wooden ship was constructed using teak, without any iron, and had a transport capacity of 400 tonnes
3.
Wood
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Wood is a porous and fibrous structural tissue found in the stems and roots of trees, and other woody plants. It is a material, a natural composite of cellulose fibers which are strong in tension embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, in a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots, Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. In 2005, the stock of forests worldwide was about 434 billion cubic meters. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy, in 1991 approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction, a 2011 discovery in the Canadian province of New Brunswick discovered the earliest known plants to have grown wood, approximately 395 to 400 million years ago. Wood can be dated by carbon dating and in species by dendrochronology to make inferences about when a wooden object was created. People have used wood for millennia for many purposes, primarily as a fuel or as a material for making houses, tools, weapons, furniture, packaging, artworks. Constructions using wood date back ten thousand years, buildings like the European Neolithic long house were made primarily of wood. Recent use of wood has changed by the addition of steel. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the climate at that time. This process is known as growth, it is the result of cell division in the vascular cambium, a lateral meristem. These cells then go on to form thickened secondary cell walls, composed mainly of cellulose, hemicellulose, if the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent, if the bark of the tree has been removed in a particular area, the rings will likely be deformed as the plant overgrows the scar. It is usually lighter in color than that near the portion of the ring. The outer portion formed later in the season is known as the latewood or summerwood. However, there are differences, depending on the kind of wood
4.
Barrel
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A barrel, cask, or tun is a hollow cylindrical container, traditionally made of wooden staves bound by wooden or metal hoops. Traditionally, the barrel was a size of measure referring to a set capacity or weight of a given commodity. For example, in the UK a barrel of beer refers to a quantity of 36 imperial gallons, wine was shipped in barrels of 119 litres. Modern barrels and casks can also be made of aluminum, stainless steel, someone who makes barrels is called a barrel maker or cooper. Barrels are only one type of cooperage, other types include, but are not limited to, buckets, tubs, butter churns, hogsheads, firkins, kegs, kilderkins, tierces, rundlets, puncheons, pipes, tuns, butts, pins, and breakers. An aging barrel is used to age wine, distilled spirits such as whiskey, brandy, or rum, beer, tabasco sauce, when a wine or spirit ages in a barrel, small amounts of oxygen are introduced as the barrel lets some air in. Oxygen enters a barrel when water or alcohol is lost due to evaporation, in an environment with 100% relative humidity, very little water evaporates and so most of the loss is alcohol, a useful trick if one has a wine with very high proof. Most beverages are topped up from other barrels to prevent significant oxidation, although others such as vin jaune, beverages aged in wooden barrels take on some of the compounds in the barrel, such as vanillin and wood tannins. The presence of these depends on many factors, including the place of origin, how the staves were cut and dried. After roughly three years, most of a barrels flavor compounds have been leached out and it is well on its way to becoming neutral, barrels used for aging are typically made of French or American oak, but chestnut and redwood are also used. Some Asian beverages use Japanese cedar, which imparts an unusual, in Peru and Chile, a grape distillate named pisco is either aged in oak or in earthenware. Some wines are fermented on barrel, as opposed to in a container like steel or wine-grade HDPE tanks. Wine can also be fermented in large tanks, which—when open to the atmosphere—are called open-tops. Other wooden cooperage for storing wine or spirits range from smaller barriques to huge casks, the tastes yielded by French and American species of oak are slightly different, with French oak being subtler, while American oak gives stronger aromas. To retain the desired measure of oak influence, a winery will replace a certain percentage of its barrels every year, some winemakers use 200% new oak, where the wine is put into new oak barrels twice during the aging process. Bulk wines are more cheaply flavored by soaking oak chips in them instead of being aged in a barrel. Sherry is stored in 600-litre casks made of North American oak, the casks, or butts, are filled five-sixths full, leaving the space of two fists empty at the top to allow flor to develop on top of the wine. NOTE, This section uses both the U. S. –Irish typical spelling whiskey and the British–Canadian typical spelling whisky, laws in several jurisdictions require that whiskey be aged in wooden barrels
5.
Float (nautical)
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Floats are airtight hollow structures, similar to pressure vessels, designed to provide buoyancy in water. Their principal applications are in watercraft hulls and aircraft floats, floating pier and pontoon bridge construction, floats make up the multipart hulls of catamarans and trimarans and provide buoyancy for floatplanes and seaplanes. They are used in bridges, floating piers, and floats anchored to the seabed for recreation or dockage. They are also used in shipbuilding and marine salvage, often deployed uninflated then pressurized to raise a sunken object, pontoons for marine industrial uses are usually fabricated from steel plate and sheet. Pontoons as parts of watercraft and aircraft are more typically molded in glass-reinforced plastic, in model building, floats can easily be carved out of solid blocks or laminated sheets of foam
6.
Phragmites
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Phragmites is a genus of four species of large perennial grasses found in wetlands throughout temperate and tropical regions of the world. The World Checklist of Selected Plant Families, maintained by Kew Garden in London, – Japan, Korea, Ryukyu Islands, Russian Far East Phragmites karka Trin. About 130 other synonyms have been proposed, and some have been widely used, arundo phragmites L. and Phragmites vulgaris Crép. Recent studies have characterised morphological distinctions between the introduced and native stands of Phragmites australis in North America, americanus – the North American genotype has been described as a distinct subspecies, subsp. Americanus, and Phragmites australis – the Eurasian genotype is sometimes referred to as subsp, altissimus Clayton is an accepted subspecies of P. australis. Phragmites australis var. marsillyanus Kerguélen is a variety of Phragmites australis. In North America, the status of Phragmites australis was a source of confusion and it was commonly considered an exotic species and often invasive species, introduced from Europe. However, there is evidence of the existence of Phragmites as a plant in North America long before European colonization of the continent. It is now known that the North American native forms of P. a. subsp, americanus are markedly less vigorous than European forms. The recent marked expansion of Phragmites in North America may be due to the more vigorous, Phragmites outcompetes native vegetation and lowers the local plant biodiversity. Phragmites forms dense thickets of vegetation that is unsuitable habitat for native fauna, Phragmites displaces native plants species such as wild rice, cattails, and native wetland orchids. Phragmites has a high ground biomass that blocks light to other plants allowing areas to turn into Phragmites monoculture very quickly. Decomposing Phragmites increases the rate of marsh accretion more rapidly than would occur with native marsh vegetation, australis is causing serious problems for many other North American hydrophyte wetland plants, including the native Phragmites australis subsp. Gallic acid released by Phragmites is degraded by ultraviolet light to produce acid, effectively hitting susceptible plants. Phragmites are so difficult to control one of the most effective methods of eradicating the plant is to burn it over 2-3 seasons. The roots grow so deep and strong that one burn is not enough, ongoing research suggests that goats could be effectively used to control the species. Phragmites australis, common reed, commonly forms extensive stands, which may be as much as 1 square kilometre or more in extent, where conditions are suitable it can also spread at 5 metres or more per year by horizontal runners, which put down roots at regular intervals. It can grow in damp ground, in standing water up to 1 metre or so deep, the erect stems grow to 2–6 metres tall, with the tallest plants growing in areas with hot summers and fertile growing conditions
7.
Drum (container)
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A drum is a cylindrical container used for shipping bulk cargo. Drums can be made of steel, dense paperboard, or plastics, drums are often certified for shipment of dangerous goods. Shipped goods must be matched with the make of drum necessary to comply with applicable regulations, drums are also called barrels in common usage. It is common to hear a drum referred to as a barrel, in the United States, 25-US-gallon drums are also in common use and have the same height. This allows easy stacking of mixed pallets, barrels can be constructed of plastic, laminated paperboard or steel. The two common sub-types of drums are the top and the welded top. The latter are almost universally called barrels in preference to drums in the United States and they cannot efficaciously either dispense or be filled with powdered goods, though they might store them very well, so are not used for such goods, being reserved for liquids transport and storage. Plastic drums are manufactured using injection blow moulding technology and have either a separate lid or a welded type top with the holes molded in. Metal drums are manufactured with cold-rolled steel sheets, welded themselves into long pipe-like sections then forged on a stamping press into drum bodies, a rolled seam is then made for the drum bottom, or bottom and top both. Some drums have reinforcing rings of thickened metal or plastic, called chimes, at four places, top, bottom and this sufficiently strengthens them so that they can readily be turned on their sides and rolled when filled with heavy materials, like liquids. Over short to medium distances, drums can be tipped and rolled on the rim while being held at an angle, balanced. Tops exist with bung holes as above, and these hybrid drums with lid can be used to ship many non-volatile liquids as well as industrial powders. Many drums are used to ship and store powdered products as well as liquids, such as beads for injection moulding, extrusion. If used to transport goods across international boundaries, they may need to have UN certification. In general, drum usage is limited to distribution of bulk products. These metal drums have two openings with flanges, once the drums are filled, the plugs are screwed in the flanges using pneumatic or hand operated bung tightener. To secure the contents of the drums against theft and adulteration during shipment, cap-seals made of metal and these cap-seals sit on top of the flanges and are crimped, using a drum cap-seal crimping tool, also called a drum cap sealer. Once cap-seals are crimped, the plugs can be unscrewed only by breaking these cap-seals, pneumatic and hand-operated cap-seal crimping tools are available
8.
Polystyrene
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Polystyrene /ˌpɒliˈstaɪriːn/ is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed, general-purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight and it is a rather poor barrier to oxygen and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year, Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging, containers, lids, bottles, trays, tumblers, as a thermoplastic polymer, polystyrene is in a solid state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled and this temperature behavior is exploited for extrusion and also for molding and vacuum forming, since it can be cast into molds with fine detail. Polystyrene is very slow to biodegrade and is therefore a focus of controversy among environmentalists, Polystyrene was discovered in 1839 by Eduard Simon, an apothecary from Berlin. From storax, the resin of the American sweetgum tree Liquidambar styraciflua, he distilled an oily substance, several days later, Simon found that the styrol had thickened into a jelly he dubbed styrol oxide because he presumed an oxidation. By 1845 Jamaican-born chemist John Buddle Blyth and German chemist August Wilhelm von Hofmann showed that the transformation of styrol took place in the absence of oxygen. They called the product metastyrol, analysis showed that it was identical to Simons Styroloxyd. In 1866 Marcelin Berthelot correctly identified the formation of metastyrol/Styroloxyd from styrol as a polymerization process, about 80 years later it was realized that heating of styrol starts a chain reaction that produces macromolecules, following the thesis of German organic chemist Hermann Staudinger. This eventually led to the substance receiving its present name, polystyrene, the company I. G. Farben began manufacturing polystyrene in Ludwigshafen, about 1931, hoping it would be a suitable replacement for die-cast zinc in many applications. Success was achieved when they developed a reactor vessel that extruded polystyrene through a tube and cutter. In 1941, Dow Chemical invented a Styrofoam process, before 1949, the chemical engineer Fritz Stastny developed pre-expanded PS beads by incorporating aliphatic hydrocarbons, such as pentane. These beads are the raw material for moulding parts or extruding sheets, BASF and Stastny applied for a patent that was issued in 1949. The moulding process was demonstrated at the Kunststoff Messe 1952 in Düsseldorf, the crystal structure of isotactic polystyrene was reported by Giulio Natta. In 1954, the Koppers Company in Pittsburgh, Pennsylvania, developed expanded polystyrene foam under the trade name Dylite, in 1960, Dart Container, the largest manufacturer of foam cups, shipped their first order. In 1988, the first U. S. ban of general polystyrene foam was enacted in Berkeley, in chemical terms, polystyrene is a long chain hydrocarbon wherein alternating carbon centers are attached to phenyl groups
9.
Timber rafting
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Timber rafting is a log transportation method in which logs are tied together into rafts and drifted or pulled across a water body or down a flatter river. It is arguably the second cheapest method of transportation of timber, both methods may be referred to as timber floating. On the other hand, rafting requires wider waterflows, Timber rafts were also used as a means of transportation of people and goods, both raw materials and man-made. Theophrastus records how the Romans imported Corsican timber by way of a raft propelled by as many as fifty masts. This practice used to be common in parts of the world, especially North America. Large pines in the black forest were called „Holländer“, as they were traded to the Netherlands, large timber rafts on the Rhine were 200 to 400m in length, 40m wide and consisted of several thousand logs. The crew consisted of 400 to 500 men, including shelter, bakeries, ovens, Timber rafting infrastructure allowed for large interconnected networks all over continental Europe. The advent of the railroad, steam boat vessels and improvements in trucking and it is still of importance in Finland. Timber rafts could be of enormous proportions, sometimes up to 600 metres long,50 meters wide, such rafts would contain thousands of logs. For the comfort of the raftsmen - which could number up to 500 - logs were used to build cabins. Control of the raft was done by oars and later on by tugboats, raft construction differs depending on the watercourse. Rocky and windy rivers saw rafts of simple, yet sometimes smart, for example, the front parts of the logs were joined together by wooden bars, while the rear parts were loosely roped together. The resulting slack allowed for easy adaptation for narrow and windy waterbeds, wide and quiet rivers, like the Mississippi River, allowed huge rafts to travel in caravans and even be chained into strings. Rafting was a method of transporting timber in the southeastern United States but, except on the Mississippi River. On Georgia’s Altamaha River, for example, the width was about forty feet. Maximum length was about 250 feet, that being the longest that could navigate The Narrows, several miles of the river that were not only very narrow, each raft had two oars forty to fifty feet long, one in the bow, the other at the stern. The oars were for steering, not propelling, the raft, the minimum raft crew was two men, the pilot who usually manned the stern oar, and his bow hand. Rafts usually had a shack for shelter and a mound of dirt for a hearth to warm by
10.
Logging
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Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. In forestry, the logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest. However, in usage, the term may be used to indicate a range of forestry or silviculture activities. Illegal logging refers to what in forestry might be called timber theft by the timber mafia and it can also refer to the harvesting, transportation, purchase, or sale of timber in violation of laws. Clearcut logging is not necessarily considered a type of logging but a harvesting or silviculture method, in the forest products industry logging companies may be referred to as logging contractors, with the smaller, non-union crews referred to as gyppo loggers. Cutting trees with the highest value and leaving those with lower value and it is sometimes called selective logging, and confused with selection cutting, the practice of managing stands by harvesting a proportion of trees. Logging usually refers to above-ground forestry logging, submerged forests exist on land that has been flooded by damming to create reservoirs. Such trees are logged using underwater logging or by the lowering of the reservoirs in question, ootsa Lake and Williston Lake in British Columbia, Canada are notable examples where timber recovery has been needed to remove inundated forests. Clearcutting, or clearfelling, is a method of harvesting that removes all the standing trees in a selected area. Silviculture objectives for clearcutting, and a focus on forestry distinguish it from deforestation, other methods include shelterwood cutting, group selective, single selective, seed-tree cutting, patch cut, and retention cutting. The above operations can be carried out by different methods, of which the three are considered industrial methods, Trees are felled and then delimbed and topped at the stump. The log is then transported to the landing, where it is bucked and loaded on a truck and this leaves the slash in the cut area, where it must be further treated if wild land fires are of concern. This ability is due to the advancement in the style felling head that can be used, the trees are then delimbed, topped, and bucked at the landing. This method requires that slash be treated at the landing, in areas with access to cogeneration facilities, the slash can be chipped and used for the production of electricity or heat. Full-tree harvesting also refers to utilization of the tree including branches. Cut-to-length logging is the process of felling, delimbing, bucking, harvesters fell the tree, delimb, and buck it, and place the resulting logs in bunks to be brought to the landing by a skidder or forwarder. This method is available for trees up to 900 mm in diameter. Harvesters are employed effectively in level to steep terrain
11.
Sergey Prokudin-Gorsky
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Sergey Mikhaylovich Prokudin-Gorsky was a Russian chemist and photographer. He is best known for his work in color photography of early 20th-century Russia. Prokudin-Gorsky was born in the estate of Funikova Gora, in what is now Kirzhachsky District. His parents were of the Russian nobility, and the family had a military history. They moved to Saint Petersburg, where Prokudin-Gorsky enrolled in Saint Petersburg State Institute of Technology to study chemistry under Dmitri Mendeleev and he also studied music and painting at the Imperial Academy of Arts. In 1890, Prokudin-Gorsky married Anna Aleksandrovna Lavrova, and later the couple had two sons, Mikhail and Dmitri, and a daughter, Ekaterina, Anna was the daughter of the Russian industrialist Aleksandr Stepanovich Lavrov, an active member in the Imperial Russian Technical Society. Prokudin-Gorsky subsequently became the director of the board of Lavrovs metal works near Saint Petersburg. He also joined Russias oldest photographic society, the section of the IRTS, presenting papers. In 1901, he established a studio and laboratory in Saint Petersburg. Perhaps Prokudin-Gorskys best-known work during his lifetime was his portrait of Leo Tolstoy, which was reproduced in various publications, on postcards. The Tsar enjoyed the demonstration, and, with his blessing, Prokudin-Gorsky got the permission, in the course of ten years, he was to make a collection of 10,000 photos. Prokudin-Gorsky considered the project his lifes work and continued his journeys through Russia until after the October Revolution. He was appointed to a new professorship under the new regime, in 1920, Prokudin-Gorsky remarried and had a daughter with his assistant Maria Fedorovna née Schedrimo. The family finally settled in Paris in 1922, reuniting with his first wife, Prokudin-Gorsky set up a photo studio there together with his three adult children, naming it after his fourth child, Elka. He died in Paris on September 27,1944, a month after the Liberation of Paris and he is buried in the Sainte-Geneviève-des-Bois Russian Cemetery. Only the viewers and ready-made triple photographs for use in them sold in any significant quantity, still life arrangements, unpopulated landscapes and oil paintings were the typical subject matter, but a few examples of color portraiture from life were also offered. Several Kromskop color views of the aftermath of the 1906 San Francisco earthquake and fire, another very notable practitioner was Adolf Miethe, with whom Prokudin-Gorsky studied in Germany in 1902. Miethe was a photochemist who greatly improved the characteristics of the black-and-white photographic materials suitable for use with this method of color photography
12.
Ochroma
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Ochroma is a genus of flowering plants in the mallow family, Malvaceae, containing the sole species Ochroma pyramidale, commonly known as the balsa tree. It is a large, fast-growing tree that can grow up to 30 m tall, balsa wood is a very lightweight material with many uses. Balsa trees are native to southern Brazil and northern Bolivia, up to southern Mexico, a member of the mallow family, O. pyramidale is native to southern Mexico to southern Brazil, but is now found in many other countries. It is a plant, which establishes itself in clearings in forests, either man-made or where trees have fallen. It grows extremely rapidly, up to 90 ft in 10–15 years, the speed of growth accounts for the lightness of the wood, which has a lower density than cork. Trees generally do not live beyond 30 to 40 years, flowers are produced from the third year onwards, typically at the end of the rainy season when few other trees are in flower. The large flowers open in the afternoon and remain open overnight. Each may contain a pool of nectar up to 1 in deep, however most pollination occurs at night. It was once thought that the main pollinators were bats, however recent evidence suggests that two nocturnal arboreal mammals, the kinkajou and the olingo, may be the primary pollinators, ecuador supplies 95% or more of commercial balsa. In recent years, about 60% of the balsa has been plantation-grown in densely packed patches of around 1000 trees per hectare and it is evergreen or dry-season deciduous, with large weakly palmately lobed leaves. Being a deciduous angiosperm, balsa is classified as a hardwood despite the wood itself being very soft and it is the softest commercial hardwood. The trees are harvested after six to 10 years of growth, the name balsa comes from the Spanish word for raft. Balsa lumber is very soft and light, with a coarse, the density of dry balsa wood ranges from 40–340 kg/m3, with a typical density of about 160 kg/m3. The wood of the tree has large cells that are filled with water. This gives the wood a spongy texture and it also makes the wood of the living tree not much lighter than water and barely able to float. For commercial production, the wood is kiln-dried for about two weeks, leaving the hollow and empty. The large volume-to-surface ratio of the resulting thin-walled empty cells gives the wood a large strength-to-weight ratio because the cells are mostly air. Unlike naturally rotted wood, that soon disintegrates in the rainforests where balsa trees grow, however, it also is valued as a component of full-sized light wooden aeroplanes, most notably the World War II de Havilland Mosquito
