What is Wood: Definition and 228 Discussions

Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material – a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. 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.
Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate.
As of 2005, the growing stock of forests worldwide was about 434 billion cubic meters, 47% of which was commercial. 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.

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  1. P

    Related Rates and wood nymphs

    1.Suppose the wood nymphs and satyrs are having a hot party in honor of Bacchus and the wine is flowing freely from the bottom of a giant cone-shaped barrel which is 12 feet deep and 6 feet in radius at the top. if the wine is disappearing at a rate of 6 cubic feet per hour, at what rate is the...
  2. L

    Calculating the Density of a Floating Block of Wood

    Homework Statement A block of wood of uniform density floats so that exactly half of its volume is underwater. The density of water is 1000 kg/m3. What is the density of the block? Homework Equations The Attempt at a Solution I tried 500 kg/m3 divided by 1000 kg/m3
  3. M

    Thermoplastic wood + help for Rapid Prototyping

    At Germany , Fraunhofer Institute succeeded to marry two paper manufacturing wood waste materials , lignin and cellulose When you apply high pressure to lignin and cellulose mixture , you get a thermoplastic which is a wood material without pores and ebony density. You can melt it and injection...
  4. Andre

    Testing Wood for Lead: Help Finding an Effective Method

    Lead in the form of -for example- Tetra ethyl lead has long been used as fuel additive, ultimately causing soil pollution. There is concern that this lead ultimately settled in wood during the growing process, which may have led to unacceptable concentrations of lead in wood. So, it would be...
  5. T

    Metal and wood common temperature for neutral feel

    Metal and wood common temperature for neutral "feel" Homework Statement Taken from the homework: At what common temperature will a block of wood and a block of metal both feel neither hot nor cold to the touch. Homework Equations I believe it is just conceptual, so I do not know if one...
  6. P

    Wood and bullet Friction Question

    Homework Statement 2 kg block of wood rests on a long tabletop. A 5g bullet moving horizontally with a speed of 150m/s is shot into the block and sticks into it. The block then slides 270cm along the table and stops A) find the speed of the block ( answer: 0.374 m/s) B)*** find the...
  7. B

    Which block has a greater final speed after being hit by a bullet?

    Homework Statement 2 bullets of the same mass are fired at the same velocities. One hits a wood block, and embeds itself. One hits a steel block, and bounces off. Both blocks are on a frictionless table. Compare the two blocks speed after. Homework Equations The Attempt at a...
  8. S

    Collision, Bullet fired into block of wood

    Homework Statement A 20.0 g bullet moving horizontally at 70.0 m/s strikes a 9.00 kg block of wood lying at rest on the pavement. The bullet embeds itself in the block of wood during the collision. Find a. the speed of the block of wood immediately after the collision, b. the...
  9. F

    Whats the chemichal composition of oak wood?

    Whats the chemical composition of oak wood? I want to know because I am trying to cut wood by changing the chemical compound of the places that i want to cut it at by putting a chemical that would bond to the wood, and the new compund of my chemical and wood would be a gas. I don't know if...
  10. C

    Determining the static and kinetic coefficients on an incline of wood on wood

    Homework Statement This was a lab task in which we are asked: Determine the static and dynamic coefficients of friction for a block of wood of mass 82.2grams on a plank of wood. PART A: To determine the static coefficient we found the angle at which point the block just started to...
  11. P

    Calculate Force Exerted by Wood on Bullet

    Homework Statement A bullet of mass 0.0022 kg initially moving at 504 m/s embeds itself in a large fixed piece of wood and travels 0.72 m before coming to rest. Assume that the acceleration of the bullet is constant. What force is exerted by the wood on the bullet? F=N Homework...
  12. B

    Constructing the Perfect Balsa Wood Beam: Tips & Tricks

    Homework Statement I'm first yar civil/struc student, we have to make a balsa wood beam with marks awarded for the mass/beam weight ratio. Anyway I'm curious as to the best way to go about this. I'm aiming for the highest moment of interia in the y direction but would also like to be able to...
  13. B

    Burning Calories, Burning Wood, Grams to Cals?

    Alright so I apologize if this questions seems less "physics" based, but I promise there is a reason I'm posting it here- if you can thoroughly explain this, I'd much appreciate it! FIRST PREMISE: I was recently reading on the forum about the question of burning a log of wood (mass) and...
  14. B

    Strain gauge to measure wood expanasivity.

    Hi! Im measuring how much wood expands in different temperatures using a strain gauge. do i need to use a wheatstone bridge circuit schematic? or else how do i heat up the wood without spoiling the strain gauge. Actually how will i heat up the wood anyway? Also how would i draw a diagram to...
  15. Y

    Maximizing Flight Time: Tips for Adjusting Flaps on a Balsa Wood Glider

    I need to adjust the flaps on a balsa wood glider so it will fly upward in a spiral, reach a maximum, and fly downward in a spiral. I don't think that the model matters. Basically, I need to get a glider to stay for a long time in the air. Any suggestions? --Thanks, Yuval Edit: The...
  16. H

    Investigating Wood Expansion & Contraction w/ Strain Gauge

    Hi i have just been given my physics coursework and wondered if anyone had any pointers or tips on how to answer? The question is on the expansion and contraction of wood with changes in temperature and humidity using a strain gauge. We have to explain how we would use lab equipment to...
  17. S

    Investigating Wood Expansion/Contraction with Strain Gauges

    hi I've just been given this piece of coursework which is the latest(2008) version and I am just wondering if I could get any help on this? thnx! :cheesy grin: The manufacturers of wood floors need to know how much the wood expands and contracts with changes in humidity and temperature. One...
  18. B

    Construct a Balsa Wood Device to Protect an Egg from Drops

    Homework Statement Objective: To produce a balsa wood device that will hold and protect an egg from breaking when released from various heights. RULES 1. The device must be constructed using ONLY balsa wood (1/8 x 1/8 in) 2. Individual pieces of balsa wood may be laminated together in any...
  19. V

    Calculating Wood Friction on Metal: Solving for Time

    Homework Statement You place a piece of wood onto a 227cm long piece of metal on a 25 angle. The \mu=.34 How long does it take for the piece of wood to reach the bottom of the metal? Homework Equations \DeltaX=227 Vi=0 a=? t=? \DeltaX=ViT+.5at^2 227=.5at^2 a=Fnet/m \mu=Ff/Fn...
  20. magi

    Wood fire in compressed air chamber?

    Hi. What happends when i put fire to wood that I have in a chamber with a pressure of about 15 kg/cm2 = 14.710 Bar = 213,3 Psi. Will it burn as usuall or much faster? Will I get a very high pressure? How High pressure can I get? Magi
  21. M

    Wood structures: story shear & unit shear question

    Homework Statement A rectangular two-story building with a wood roof and floor system and masonry walls is analyzed to determine seismic forces. Given: I=1, roof dead load D=15psf, floor load=25psf including partition load. Exterior wall dead load D=80 psf along both long and short walls...
  22. S

    Wood I Beam of dimensional lumber

    My first post here. I've lurked around, used the search function - but I can't seem to find what I'm looking for. So I'm hoping someone can help me. I am designing a shed for my backyard. It will be used to house a storage tank for water heated by solar collectors on the roof of said shed. I...
  23. K

    Modulus of Elasticity for wood

    Hi. I was wondeirng if anyone knew the modulus of elasticity for Basswood and Balsa wood under compression.. I found numbers but its all different.
  24. H

    How Can I Burn Wood Anytime Using Solar Power?

    Hi, I'm new to this forum, and from what I've seen so far, there are some very intelligent people posting here, and I'm hoping someone will have an answer for me. It's a two part question basically boiling down to one point. I've recently become involved in wood burning as a hobby...
  25. A

    Conservation of momentum and wood ball problem

    Problem: A 20.0 kg wood ball hangs from a 1.50 m-long wire. The maximum tension the wire can withstand without breaking is 300 N. A 0.900 kg projectile traveling horizontally hits and embeds itself in the wood ball. What is the largest speed this projectile can have without causing the cable...
  26. F

    Converting wood joists to steel

    I would like to know if there are any guides or tables that will allow you to convert 2x Douglas Fir joists to an equivalent rectangular steel tube.
  27. S

    Kinetic friction of a wood block

    So the problem states: A 1.4 kg wood block is launched up a wooden ramp that is inclined at a 22 deg angle. The block's initial speed is 14 m/s. Use Uk = 0.20 for the coefficient of kinetic friction for wood on wood. U = mu... (a) What vertical height does the block reach above its...
  28. E

    Help with pressure differences-sponge and wood

    hi,i have been doing experiments with individual pressure sensors, while attaching the sensor to my thumb, if i press my thumb onto a hard surface the pressure recorded is very high, but when i push my thumb onto a soft surface, like a sponge i have to press a lot harder to get a high pressure...
  29. D

    Lifting Wood Without a Cam: Is This Idea Any Good?

    Hi, I am creating a mechanism that needs to be able to lift a plank of wood up and down arpund a pivot. However, there isn't enough space below the wood to enable me to place a cam. So i thought I might be able to place a cam above the wood - although this would mean the follower would have no...
  30. Making Wood Alcohol/Methyl Alcohol

    Something I've been wondering a lot lately is how would you make your own wood alcohol? It seems somewhat simple and I can't find any decent things on google about it. Anyone know how to make? Or have a step by step process on it. Edit: Actually I think I am looking for ethyl alcohol. But both...
  31. A

    Is it possible to accurately measure the Young's modulus of wood?

    Hello, I am currently carrying out an dynamic investigation of young's modulus for various linear materials such as copper, steel, and nylon but I am unsure how to find the modulus for wood. I have several ideas including fixing one end of a sample length of wood to bench while placing a...
  32. A

    Building a Balsa Wood Tower- Tips and Ideas

    I was assigned to build a structure out of balsa wood (1/8 X 1/8 inch) and glue. It has to be between 7.5 and 8.5 inches high , cannot have mass greater than12 grams, and has to be able support at least 60 pounds (this would only get me about a C) while withstanding torque. I've been...
  33. P

    Wood vs Brick Homes: Which is Better & Why?

    From looking at my book, brick has a resistance value of 0.43 and wood has a resistance value of 5.0. So wood should be a much better insulator. However homes are usually built with brick. Good homes have a double layer but air only has a resistance value of 1.0 Brick homes are considered...
  34. M

    Buoyancy of wood block problem help

    A block of wood floats on water. A layer of oil is now poured on top of the water to a depth that more than covers the block. If 91% of the wood is submerged in water before the oil is added, find the fraction submerged when oil with a density of 883 kg/m3 covers the block. (Do not neglect the...
  35. infraray

    How Does Heat Affect the Bullet-Wood Problem?

    How is the bullet-wood problem different in setup if: a)the bullet stops in the wood b)if the bullet goes through the wood? Is it that (a) would be an inelastic and (b) would use conservation of momentum? Other question is how can energy loss by heat be calculated by this type of...
  36. B

    A 2.0 kg wood block is launched up a wooden ramp

    A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 30 degree angle. The block's initial speed is 10 m/s. The coefficient of kinetic friction of wood on wood is .200 1)What vertical height does the block reach above its starting point? 2)What speed does it have when it...
  37. B

    A 2.0 kg wood block is launched up a wooden ramp

    Can someone help me with this problem. A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 30 degree angle. The block's initial speed is 10 m/s. The coefficient of kinetic friction of wood on wood is .200 1)What vertical height does the block reach above its starting...
  38. B

    Bullet Strikes A Block Of Wood

    A 10 gram bullet with a horizontal speed of 400m/s hits a block of wood and penetrates 12 cm. a. what is the frictional force? b.how long does it take the bullet to come to rest I have the answers but cannot figure out how to get there. I set my initial velocity to 400 m./s, making my...
  39. T

    .Calculating Time for .22 Rifle Bullet to Stop in Soft Wood

    Ok, so here's my question: A .22 rifle bullet, traveling at 350 m/s, strikes a block of soft wood, which it penetrates to a depth of 0.130 m. The block of wood is clamped in place and doesn't move. The mass of the bullet is 1.80 g. Assume a constant retarding force. I know this has already...
  40. L

    When Does Normal Force on a Wood Block Equal 0?

    Hi. I have a question. When is the normal force on a wood block equal to zero?
  41. H

    Calculating Force and Thickness of a 8.0g Bullet Passing Through Wood

    A 8.0g bullet traveling at 400m/s passes through a heavy block of wood in 4.0x10^-4s, emerging with a velocity of 100m/s. Ignore the motion of the wood. 1) What is the force exerted by the block on the bullet? 2) What is the force exerted by tbe bullet on the block? 3) How thick is the...
  42. wolram

    Flimsy bits of wood and tensioned strings

    How do they make them so that these exquisite notes come from them, i mean they are flimsy bits of wood and tensioned strings, is there a (science) behind it ?
  43. J

    Elastic Collision of two wood blocks

    Two blocks are free to slide along a frictionless wooden track ABC as shown in Figure P9.20. The block of mass m1 = 5.07 kg is released from A. Protruding from its front end is the north pole of a strong magnet, repelling the north pole of an identical magnet embedded in the back end of the...
  44. TheStatutoryApe

    Expert Tips for Making a Wooden Puzzle Box & Working with Polymer Clay

    Help With Clay and Wood... I have a couple projects I have been putting off for a while because I need advice before beginning them. Firstly I have been wanting to make a puzzle box. The same sort of idea as the one in Hellraiser except that I will likely be using wood and mine won't...
  45. K

    Does Wood Create Noise When Vibrated?

    My question is quite simple: It is common knowledge that most metals make a lot of noise when in contact with moving/vibrating parts. Some examples are the hood of your car, or a computer case with fans on it. Does wood have the same characteristic? I want to use wood to mount a few fans...
  46. G

    Constant Speed for a Sliding Wood Box

    A 2.0 kg wood box slides down a vertical wood wall while you push on it at a 45 degree angle. What magnitude of force should you apply to cause the box to slide down at a constant speed? (Problem 51, Chapter 5, Knight) I can't figure out this problem and do not have the text to refer to...
  47. S

    Designing a Balsa Wood Beam: Max Strength, Min Weight

    Hi for school i need to design a balsa wood beam. Winner is judged be strength to weight ratio. i have searched around and found all the stress and strain values for balsa wood at different densitys etc... now my dilemma is that i have to use formulas to design this beam before it is...
  48. G

    Wood block sliding on 25 degree angle

    A wooden block slides directly down an inclined plane, at a constant velocity of 6 m/s. How large is the coefficient of kinetic friction, if the plane makes an angle of 25 degrees with the horizontal?
  49. P

    Help! John Needs to Carry a Long Piece of Wood

    calculus help :( John has to carry a long piece of wood horizontally around the corner from a hallway of width 2 m to a hallway of width 2.5 m. Assuming that the piece of wood has no width, what is the maximum length of this piece of wood (in meters)? Give answer to two decimal places. i do...
  50. S

    Can Wood Melt in Space? Find Out the Surprising Answer Here

    Can wood melt if... dont tell me like you can't do that I am just talkin in like IF you can now if you get a piece of wood into space, and heat it, without oxygen it can't burn so will it melt? or bend or something? or just do nothing
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