sentence-transformers/squad huggingface dataset:
Passage: In the case of the ring-porous hardwoods there seems to exist a pretty definite relation between the rate of growth of timber and its properties. This may be briefly summed up in the general statement that the more rapid the growth or the wider the rings of growth, the heavier, harder, stronger, and stiffer the wood. This, it must be remembered, applies only to ring-porous woods such as oak, ash, hickory, and others of the same group, and is, of course, subject to some exceptions and limitations.

Question: Ring-porous hardwoods have a clear relationship between their properties and what other factor?

Question: Is harder, heavier wood indicated by narrower or wider growth rings?

Question: What kind of wood with a name that starts with "H" is a ring-porous hardwood?

Question: If the growth rings are wider, was the growth of the tree slower or more rapid?

Question: What is the only kind of wood that will definitely be harder and stronger when it grows faster?
Passage: In ring-porous woods of good growth it is usually the latewood in which the thick-walled, strength-giving fibers are most abundant. As the breadth of ring diminishes, this latewood is reduced so that very slow growth produces comparatively light, porous wood composed of thin-walled vessels and wood parenchyma. In good oak these large vessels of the earlywood occupy from 6 to 10 percent of the volume of the log, while in inferior material they may make up 25% or more. The latewood of good oak is dark colored and firm, and consists mostly of thick-walled fibers which form one-half or more of the wood. In inferior oak, this latewood is much reduced both in quantity and quality. Such variation is very largely the result of rate of growth.

Question: Which specific type of wood within ring-porous woods have more fibers to make it strong?

Question: When there is less latewood, what is diminishing?

Question: Does slow or rapid growth make relatively porous, light wood?

Question: What kind of oak has just 6-10% volume of large vessels in the log?

Question: What kind of fibers are in the latewood of good oak, making it very firm?
Passage: Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in a closed forest, and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferred. This is particularly the case in the choice of hickory for handles and spokes. Here not only strength, but toughness and resilience are important. The results of a series of tests on hickory by the U.S. Forest Service show that:

Question: What term is sometimes used for wood with wide rings?

Question: Do young trees grow more quickly in open stands or in a closed forest?

Question: What property is important to manufacturers who use "second-growth" hardwood?

Question: What specific kind of "second-growth" hardwood is often used to make handles and spokes?

Question: What organization tested hickory to find out about its properties?
Passage: In the diffuse-porous woods, the demarcation between rings is not always so clear and in some cases is almost (if not entirely) invisible to the unaided eye. Conversely, when there is a clear demarcation there may not be a noticeable difference in structure within the growth ring.

Question: What kind of wood often has ring divisions that can't even be seen by looking at it?

Question: In diffuse-porous woods, if the demarcation between rings is obvious, what type of difference within the ring might not be?

Question: What adjective describes how our eyes function without a tool like a microscope to help?
Passage: In diffuse-porous woods, as has been stated, the vessels or pores are even-sized, so that the water conducting capability is scattered throughout the ring instead of collected in the earlywood. The effect of rate of growth is, therefore, not the same as in the ring-porous woods, approaching more nearly the conditions in the conifers. In general it may be stated that such woods of medium growth afford stronger material than when very rapidly or very slowly grown. In many uses of wood, total strength is not the main consideration. If ease of working is prized, wood should be chosen with regard to its uniformity of texture and straightness of grain, which will in most cases occur when there is little contrast between the latewood of one season's growth and the earlywood of the next.

Question: What kind of wood has all similarly sized vessels?

Question: What rate of growth in a tree will make the wood from it stronger than trees that grow very slowly or very quickly?

Question: The capability of diffuse-porous woods to carry what substance is spread out in the growth ring?

Question: What division of trees are diffuse-porous woods more similar in growth rate to than ring-porous woods?

Question: Does uniformity of the texture and grain of wood usually result from much or little contrast between earlywood and latewood?
Passage: Structural material that resembles ordinary, "dicot" or conifer wood in its gross handling characteristics is produced by a number of monocot plants, and these also are colloquially called wood. Of these, bamboo, botanically a member of the grass family, has considerable economic importance, larger culms being widely used as a building and construction material in their own right and, these days, in the manufacture of engineered flooring, panels and veneer. Another major plant group that produce material that often is called wood are the palms. Of much less importance are plants such as Pandanus, Dracaena and Cordyline. With all this material, the structure and composition of the structural material is quite different from ordinary wood.

Question: What's another term used for "conifer" wood?

Question: What type of plants produce material that is referred to as "wood" even though it is technically not?

Question: What monocot plant produces "wood" by the same name that's often used for flooring and veneer?

Question: While we call bamboo "wood," what botanical family does it belong to?

Question: Along with bamboo, what's the other monocot that's a major source of so-called "wood"?
Passage: The single most revealing property of wood as an indicator of wood quality is specific gravity (Timell 1986), as both pulp yield and lumber strength are determined by it. Specific gravity is the ratio of the mass of a substance to the mass of an equal volume of water; density is the ratio of a mass of a quantity of a substance to the volume of that quantity and is expressed in mass per unit substance, e.g., grams per millilitre (g/cm3 or g/ml). The terms are essentially equivalent as long as the metric system is used. Upon drying, wood shrinks and its density increases. Minimum values are associated with green (water-saturated) wood and are referred to as basic specific gravity (Timell 1986).

Question: Which property of wood reveals the most about its quality?

Question: In addition to lumber strength, what important indicator of wood's quality can be determined using specific gravity?

Question: What measurement is expressed in mass per unit substance?

Question: When wood dries and shrinks, what happens to its density?

Question: When wood is described as "green," what does "green" mean?
Passage: Wood density is determined by multiple growth and physiological factors compounded into “one fairly easily measured wood characteristic” (Elliott 1970).

Question: Along with growth, what kind of factors determine the density of wood?

Question: Into how many characteristics are the factors of wood combined?

Question: What author called wood's density "fairly easily measured"?
Passage: Age, diameter, height, radial growth, geographical location, site and growing conditions, silvicultural treatment, and seed source, all to some degree influence wood density. Variation is to be expected. Within an individual tree, the variation in wood density is often as great as or even greater than that between different trees (Timell 1986). Variation of specific gravity within the bole of a tree can occur in either the horizontal or vertical direction. :)

Question: What should be anticipated because of the many factors that influence wood's density?

Question: What specific type of growth has an effect on the density of wood?

Question: Which part of a tree can have vertical or horizontal variation in its specific gravity?

Question: Variation in what measurement is sometimes greater within one tree than from one tree to another?

Question: What tiny object's source plays a role in determining wood density?
Passage: It is common to classify wood as either softwood or hardwood. The wood from conifers (e.g. pine) is called softwood, and the wood from dicotyledons (usually broad-leaved trees, e.g. oak) is called hardwood. These names are a bit misleading, as hardwoods are not necessarily hard, and softwoods are not necessarily soft. The well-known balsa (a hardwood) is actually softer than any commercial softwood. Conversely, some softwoods (e.g. yew) are harder than many hardwoods.

Question: What term do we use for the wood that comes from pine trees?

Question: What kind of wood does an oak tree have?

Question: Is balsa a softwood or a hardwood?

Question: What's an example of a softwood that isn't "soft," and is actually harder than a lot of hardwoods?

Question: What's the scientific name for trees like the oak with broad leaves?
Passage: There is a strong relationship between the properties of wood and the properties of the particular tree that yielded it. The density of wood varies with species. The density of a wood correlates with its strength (mechanical properties). For example, mahogany is a medium-dense hardwood that is excellent for fine furniture crafting, whereas balsa is light, making it useful for model building. One of the densest woods is black ironwood.

Question: What kind of relationship exists between a tree's properties and its wood's properties?

Question: What property of wood varies according to species?

Question: What property of wood has a correlation to its density?

Question: Is mahogany a hardwood or a softwood?

Question: What hobby is balsa wood often used for?
Passage: The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium, potassium, sodium, magnesium, iron, and manganese) by weight. Wood also contains sulfur, chlorine, silicon, phosphorus, and other elements in small quantity.

Question: What approximate percentage of carbon does wood have?

Question: What element makes up about 6% of the chemical composition of wood?

Question: About what percentage of wood is composed of nitrogen?

Question: Which element in wood composes about 42% of its weight?

Question: What element joins potassium, calcium, manganese, iron, and sodium to make a combined 1% of the chemical composition of wood?
Passage: Aside from water, wood has three main components. Cellulose, a crystalline polymer derived from glucose, constitutes about 41–43%. Next in abundance is hemicellulose, which is around 20% in deciduous trees but near 30% in conifers. It is mainly five-carbon sugars that are linked in an irregular manner, in contrast to the cellulose. Lignin is the third component at around 27% in coniferous wood vs. 23% in deciduous trees. Lignin confers the hydrophobic properties reflecting the fact that it is based on aromatic rings. These three components are interwoven, and direct covalent linkages exist between the lignin and the hemicellulose. A major focus of the paper industry is the separation of the lignin from the cellulose, from which paper is made.

Question: How many main components make up wood, not counting water?

Question: What's the name for the crystalline polymer derived from glucose?

Question: After cellulose, what component is most plentiful in wood?

Question: What kind of trees have about 30% hemicellulose?

Question: Which of the three main components of wood is used to manufacture paper?
Passage: In chemical terms, the difference between hardwood and softwood is reflected in the composition of the constituent lignin. Hardwood lignin is primarily derived from sinapyl alcohol and coniferyl alcohol. Softwood lignin is mainly derived from coniferyl alcohol.

Question: What component of wood determines whether it is hardwood or softwood?

Question: Which wood has lignin that comes primarily from one type of alcohol?

Question: Which type of alcohol mainly becomes softwood lignin?

Question: In addition to coniferyl alcohol, what other alcohol is in hardwood lignin?

Question: Which kind of wood contains lignin derived from two main alcohol sources?
Passage: Aside from the lignocellulose, wood consists of a variety of low molecular weight organic compounds, called extractives. The wood extractives are fatty acids, resin acids, waxes and terpenes. For example, rosin is exuded by conifers as protection from insects. The extraction of these organic materials from wood provides tall oil, turpentine, and rosin.

Question: What's the name for the low molecular weight organic compounds in wood?

Question: Along with fatty acids, what kind of acids are in the extractives in wood?

Question: Wood extractives include resin and fatty acids, terpenes, and what other component?

Question: What do conifers use rosin to protect themselves from?

Question: Along with tall oil and rosin, what commercial product do we get from wood's extractives?
Passage: Wood has a long history of being used as fuel, which continues to this day, mostly in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer. Adding a woodstove or fireplace to a home is often felt to add ambiance and warmth.

Question: What type of wood is preferred as fuel?

Question: What type of wood burns quickly and makes more smoke than hardwood?

Question: What type of areas use more wood for fuel?

Question: What benefit besides the cozy atmosphere would a wood-burning fireplace add to a home?
Passage: Wood has been an important construction material since humans began building shelters, houses and boats. Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept wet (it also served for water pipe before the advent of more modern plumbing).

Question: What wood is decay-resistant when wet?

Question: What plumbing component was once made out of elm?

Question: Until the late 19th century, what vessels were almost always wooden?

Question: What significant purpose has wood been used for as long as humans have built shelters?

Question: Other than boats, what do people often build with wood?
Passage: Wood to be used for construction work is commonly known as lumber in North America. Elsewhere, lumber usually refers to felled trees, and the word for sawn planks ready for use is timber. In Medieval Europe oak was the wood of choice for all wood construction, including beams, walls, doors, and floors. Today a wider variety of woods is used: solid wood doors are often made from poplar, small-knotted pine, and Douglas fir.

Question: What term is used in North America for wood used in construction?

Question: Outside of North America, if someone said "lumber," to what would they be referring?

Question: What do people outside of North America call the sawn boards used for building?

Question: What was the preferred wood for construction in Medieval Europe?

Question: For modern solid wood doors, what wood is often used in addition to small-knotted pine or poplar?
Passage: New domestic housing in many parts of the world today is commonly made from timber-framed construction. Engineered wood products are becoming a bigger part of the construction industry. They may be used in both residential and commercial buildings as structural and aesthetic materials.

Question: What type of construction is often used now to build homes in much of the world?

Question: In addition to residential applications, what type of buildings often have engineered wood components?

Question: Along with decorative components, what type of building materials can be engineered from wood?

Question: What industry benefits greatly from engineered wood products?
Passage: In buildings made of other materials, wood will still be found as a supporting material, especially in roof construction, in interior doors and their frames, and as exterior cladding.

Question: What might wood be used for in a building made from brick or other materials?

Question: What crucial part of a house is often constructed from wood?

Question: Wood might be used to construct what exterior component of a building?

Question: Inside a building, what wooden things might you open to enter or leave rooms?
Passage: Engineered wood products, glued building products "engineered" for application-specific performance requirements, are often used in construction and industrial applications. Glued engineered wood products are manufactured by bonding together wood strands, veneers, lumber or other forms of wood fiber with glue to form a larger, more efficient composite structural unit.

Question: What holds together an engineered wood product?

Question: Engineered wood products are often used in construction, but what other major type of applications do they have?

Question: What requirements do engineered wood products meet?

Question: What efficient type of unit does the process of "engineering" wood result in?

Question: Wood fibers from wood strands, lumber, and what other source can be glued together to make larger units?
Passage: These products include glued laminated timber (glulam), wood structural panels (including plywood, oriented strand board and composite panels), laminated veneer lumber (LVL) and other structural composite lumber (SCL) products, parallel strand lumber, and I-joists. Approximately 100 million cubic meters of wood was consumed for this purpose in 1991. The trends suggest that particle board and fiber board will overtake plywood.

Question: What category do composite panels, strand board, and plywood all fit into?

Question: What's another word for glued laminated timber?

Question: What does LVL stand for?

Question: If current building trends continue, what material will be replaced by particle and fiber board?

Question: About how many cubic meters of wood was used in 1991 to make products like glulam, LVL, and structural composite lumber?
Passage: Wood unsuitable for construction in its native form may be broken down mechanically (into fibers or chips) or chemically (into cellulose) and used as a raw material for other building materials, such as engineered wood, as well as chipboard, hardboard, and medium-density fiberboard (MDF). Such wood derivatives are widely used: wood fibers are an important component of most paper, and cellulose is used as a component of some synthetic materials. Wood derivatives can also be used for kinds of flooring, for example laminate flooring.

Question: What material results from chemically breaking down wood?

Question: What's the abbreviation for medium-density fiberboard?

Question: How is wood broken down into chips and fibers?

Question: What type of flooring can be made from wood derivatives?

Question: What widely-used product is almost always made of wood fibers?
Passage: Wood has always been used extensively for furniture, such as chairs and beds. It is also used for tool handles and cutlery, such as chopsticks, toothpicks, and other utensils, like the wooden spoon.

Question: What category of products usually made from wood includes chairs?

Question: What wooden utensil could you stir a pot of soup with?

Question: Which parts of tools are sometimes made out of wood?

Question: What pieces of furniture that most people use every night can be made out of wood?

Question: What special wooden utensils do many people use to eat Chinese takeout?
Passage: Further developments include new lignin glue applications, recyclable food packaging, rubber tire replacement applications, anti-bacterial medical agents, and high strength fabrics or composites. As scientists and engineers further learn and develop new techniques to extract various components from wood, or alternatively to modify wood, for example by adding components to wood, new more advanced products will appear on the marketplace. Moisture content electronic monitoring can also enhance next generation wood protection.

Question: What could we monitor electronically that could help inform new methods of wood protection?

Question: Development in the wood manufacturing industry include using lignin to make what substance?

Question: Instead of rubber, what important part of a car might someday be replaced by components of wood?

Question: What material might be developed from wood that could make clothes that resist wear and tear?

Question: In addition to extracting components from wood, what might scientist do by adding components, for example, to make innovative products?
Passage: Wood has long been used as an artistic medium. It has been used to make sculptures and carvings for millennia. Examples include the totem poles carved by North American indigenous people from conifer trunks, often Western Red Cedar (Thuja plicata), and the Millennium clock tower, now housed in the National Museum of Scotland in Edinburgh. It is also used in woodcut printmaking, and for engraving.

Question: Along with sculptures, what type of art have people been making out of wood for centuries?

Question: What did indigenous people in North America make out of the trunks of conifers?

Question: What type of tree was often used for totem poles?

Question: What city in Scotland would you visit to see the Millennium clock tower?

Question: What museum exhibits the Millennium clock tower?
Passage: Certain types of musical instruments, such as those of the violin family, the guitar, the clarinet and recorder, the xylophone, and the marimba, are traditionally made mostly or entirely of wood. The choice of wood may make a significant difference to the tone and resonant qualities of the instrument, and tonewoods have widely differing properties, ranging from the hard and dense african blackwood (used for the bodies of clarinets) to the light but resonant European spruce (Picea abies), which is traditionally used for the soundboards of violins. The most valuable tonewoods, such as the ripple sycamore (Acer pseudoplatanus), used for the backs of violins, combine acoustic properties with decorative color and grain which enhance the appearance of the finished instrument.

Question: What kind of wood are clarinet bodies made from?

Question: What expensive wood with a prized color is used to make the backs of violins?

Question: What category of wood is often used for musical instruments?

Question: What's the common name for Picea abies?

Question: Along with resonance, what property of an instrument will be affected by the wood used to make it?
Passage: Despite their collective name, not all woodwind instruments are made entirely of wood. The reeds used to play them, however, are usually made from Arundo donax, a type of monocot cane plant.

Question: What type of instruments with a misleading name aren't always made completely out of wood?

Question: What are woodwind instrument's reeds often made out of?

Question: Is the Arundo donax a monocot or dicot cane plant?

Question: What objects do musicians have to have in order to play woodwind instruments?