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. M

    Why Houses are Built with Wood, Not Steel

    A question I have is more a curiosity. We have skyscrapers and tall buildings made of steel, but why is it whenever I go look at some housing projects and developments, those houses are built with wood frames? Right away I think of cost which is probably the most obvious answer, but I am not...
  2. Pengwuino

    Why is my dremel having trouble cutting wood?

    Why can't you cut wood... Ok so i have this dremel... 35000rpm and cordless. I got this mini-saw attachment shown here... http://www.dremel.com/html/home_fr.html Now i have this piece of wood and it has holes in it in a neat grid pattern (if anyone knows waht kind of wood has that). Its...
  3. W

    Calculating Spring Stretch in a Horizontal Setup

    A 171 g wood block is firmly attached to a very light horizontal spring, as shown in the figure below. The block can slide along a table where the coefficient of friction is 0.306. A force of 20.9 N compresses the spring 17.2 cm. If the spring is released from this position, how far beyond its...
  4. I

    Build a Balsa Wood Bridge: Explaining Arches & Compressive Strength

    Can anyone or does anyone know where I can get a good explanation of how to figure out how big an arch should be for a bridge? I am thinking of making one for our competition, and if I can't get that to work right, I will switch to a king post deisgn. Oh, and is it true balsa and other...
  5. U

    Mechanical properties of Yew wood

    Hi everyone, As part of my AS level physics coursework I’ve decided to produce a report on the physics behind why yew wood was used to create longbows. The problem I’m having is that because yew wood is no longer used in modern engineering so no reference books at my local university library...
  6. I

    Anyone good with wood and bridges?

    Hi everyone! I haven't been here in a while, and I see there've been a lot of changes. The place looks as groovy as ever. :smile: I have just been assigned a bridge builiding project. We're supposed to make the bridge out of only wood that ways 25 grams or less and be able to...
  7. S

    What causes the ticking sound in a wood stove?

    wood stove "ticking" sound I have a question about something I've wondered about since I was a child and possibly someone will know the answer. What causes the "ticking" sound when a wood stove heats up? Those of you who have a wood stove will know what I'm talking about. I'm guessing it...
  8. F

    What is the speed of the bullet after it is fired into a wood block?

    I'm stuck on this problem.. My futile attempt: the wood block's initial momentum is zero so it's m_b v_b = (m_b + m_w) v_f Where m_w is the mass of the wooden block. In order to get the bullet's velocity (which is v_b) I need v_f which is the final velocity of both the bullet and the...
  9. W

    Final Resting Place of a broken wood stick loaded with potential energy

    If a 102 foot 2500 lbs. semi rigid straight wood stick (aka bow) is placed in a vice (a really big one with no give) and loaded with energy by pulling at the top, 50 feet above the vice at a 60 degree angle to the ground with a rope ("0" lbs.), where would the stick land if the stick...
  10. F

    Velocity of wood block down an incline

    A 2.0 kg wood block is launched up a wooden ramp that is inclined at a angle. The block's initial speed is 10 m/s . The coefficient of kinetic friction of wood on wood is .200. So that's the intro... The first question is to get the hight it reachers on the incline and I got that right =...
  11. H

    Block of wood friction problem

    a 7 g bullet fires into a 1kg block of wood held in a vise, will penetrate the block a depth of 8.00 cm . this block of wood is placed on frictionless horizontal surface, and a 7.00 g bullet is fired from the gun into the block. to what depth will the bullet penetrate the block ? I bang my...
  12. F

    Wood block coeffiecent of friction

    I also need help with this problem, it involves energy and i just can't crack the problem by using what i know, i can't even start it, so here it is: A wooden Block whose intitial speed is 6 m/s starts to slide up an incline plane at 25 degrees above the horizontal. a)if the coeffiecent of...
  13. Gara

    A question about water and wood.

    Okay so this morning I picked up a very brand new copy of the Discworld book, "Going Postal". http://homepage.ntlworld.com/ak_gara/Lookie.jpg Here is a little snippit from the first page. My question is, is this even possible, if yes, why, if no, why? I'm guessing it's just being...
  14. W

    What force, in Newtons, does the wood exert on the bullet?

    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. 1.) What force, in Newtons, does the wood exert on...
  15. E

    Why Does Metal Melt but Wood Doesn't?

    why is that metal can melt into liquid form but not wood, can anyone help me, thx
  16. A

    Exploring the Possibilities of Wood and Water

    to start with i really know almost nothing about this, just curios. What if one took wood, put it into a vacuum and heated it up, a lot, since all solids turn to liquids (a fact I am sure is arguable), would the effect be liquid wood? Also, what if a ball of water was hurled into the sun...
  17. T

    PE and KE of a wood block

    If a block of wood is placed on a hilly frictionless track, would the velocity stay constant at the top of each hill if the height of each hill was the same? Since as the block of wood slides down a hill, it gains kenetic energy looses potential energy, but as it rises up the hill, the PE...
  18. E

    Thermal Expansitivity of Hard Wood

    hey wassup every1.my first post lol.neway, I've got a question which i cnt seem to find the answer to anywhere else so I am hopin one of u lot could help me out. anyway here's the question. How do i find out the percentage error of a hardwood ruler compared to the actual graduations of the ruler...
  19. J

    Wood Car Ramp Impacts: Will Bouncing Affect Force?

    Situation: A wood car with 2 eggs as passengers goes down a 2.43 meter ramp at 40 degrees. The car has a crumple zone on the front to absorb some impact. If the car bounces when it hit the cement block at the end of the ramp, how will the bouncing affect the force the car experiences on impact?
  20. J

    How to convert wood burning to electric?

    This may be a long shot, but here goes... Does anyone know of a way to convert a cast iron wood burning stove to electric. It seems possible since you can replace elements and burners on normal stoves. Any thoughts or information would be greatly appreciated. Thanks, Jeremy
  21. E

    Burning wood with magnifying glass

    Hi, In our class, we were asked whether it's practical to use a magnifying glass to focus sunlight to burn wood. One question really bothers me. Could somebody please explain to me how the focal ratio (focal length of converging lens divided by its diameter) affects the temperature of the...
  22. E

    Burning wood with a magnifying glass

    Hi, In our class, we were asked whether it's practical to use a magnifying glass to focus sunlight to burn wood. One question really bothers me. Could somebody please explain to me how the focal ratio (focal length of converging lens divided by its diameter) affects the temperature of the...
  23. A

    Initial Speed of 5.5g Bullet Fired into 22.6g Wood Block

    A 5.5 g bullet is fired into a block of wood with a mass of 22.6g. The wood block is intially at rest on a 1.5m tall post. After the collision, the wood block and bullet land 2.5m from the base of the post. Find the initial speed of the bullet.
  24. C

    Solving for Initial Speed of a 5.5g Bullet Impacting Wood Block

    I need help with this. I don't know what equation to use. A 5.5g bullet is fired into a block of wood w/a mass of 22.6g. the wood block is initially at rest on a 1.5m tall post. after the collision, the wood block and bullet land 2.5m from the base of the post. how do you find the initial...
  25. C

    Solve Wood Block Collision: 5.5g Bullet, 22.6g Wood, 1.5m Post

    I need help with this problem. I don't know what equation to use. A 5.5g bullet is fired into a block of wood w/a mass of 22.6g. The wood block is initially at rest on a 1.5m tall post. After the collision, the wood block and bullet land 2.5m from the base of the post. What is the initial...
  26. M

    Young's Modulus of wood and glass

    Hello, I was wondering if anyone could tell me the young's modulus of: Graphite, Wood, Steel, Glass, Titanium, and Aluminium... I know this is a strange thing to ask, but it would really help me understand more fully the way Graphite compares with other materials. Search engines...
  27. fffbone

    Best Wood for Constructing Heavy-Weight Apparatus

    This is a question that has been hunting me for ages: which type of wood would be best for constructing a apparatus to hold the largest amount of weight with the smallest mass? I would appreciate it very much if someone can give me some help.
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