I. organizational moment
Checking readiness for the lesson.
II. lesson topic message
Wood is a natural construction material. Lumber.
III. motivation for learning activities
Wood is one of the most important and widespread materials. The ease of processing and the variety of species made it possible to use wood for a wide variety of jobs. Each wood product has its own requirements. To correctly determine which wood should be used for a product, you need to know the characteristics of each species.
IV. formation of knowledge and skills
Historical information. (slide No. 1)
It is difficult to name an area of human activity where wood was not involved. Already in the early stages of development, man began to use this material. A little later, wood began to be used for construction (houses, bridges, ships), to make various household equipment, furniture, dishes, musical instruments and much more.
With the advent of crafts, wood became one of the first construction materials for the manufacture of spinning, weaving, milling, pottery and other machines. It was widely used in the car, ship, auto and aircraft industries. Currently, products of thousands of names and purposes are manufactured.
Structure of wood (slide No. 2)
The structure of wood can be seen in its cross section, in which the pith, bark and annual layers are clearly visible. For a more complete understanding of the structure of wood, it is necessary to consider three main sections of the trunk – transverse, radial and tangential.
On a cross section, the annual layers have the form of concentric circles, on a radial section – longitudinal stripes, on a tangential section – sinuous cone-shaped lines. In addition, in the cross section you can see light medullary rays directed from the core to the cortex. The dark colored part of the trunk is called the core, and the light colored part is called the sapwood.
Wood species (slide No. 3)
Coniferous species. Coniferous wood has a lower density, and therefore is easier to process and has higher heat-saving properties.
The group of coniferous species includes the following species:
- Pine –
the most common coniferous tree. The color of its wood can be brown, reddish, yellowish and almost white with slight streaks of red. When dry, pine is light and pliable for carpentry. Furniture, windows, doors, etc. are made from it. Wood is well processed with dyes and varnishes.
- Spruce –
softer than pine, but it has a large number of small and medium knots, which makes it difficult to use in critical carpentry structures. The texture is inexpressive, it is less moisture resistant, and is more likely to rot. In carpentry it is used for non-critical furniture designs.
- Fir –
It is used on a par with spruce, although it has reduced physical and mechanical properties.
- Larch –
occupies a special place among other coniferous species. Its wood has a red-brown, sometimes brown tint and is characterized by high strength (stronger than oak) and moisture resistance. It is used in building structures where high strength and resistance to rotting are required, and is used for the manufacture of parquet.
- Cedar –
has whitish-yellow wood with different color shades depending on where it grows. Wood is not very durable or dense. Cedar is a good material for carving. It is finished mainly with wax.
- Juniper –
coniferous shrub, trunk diameter can be up to 10-15 centimeters. Strong, thin-layered wood is well processed and polished, and has a specific smell. It is used for the manufacture of small parts, for turning, for carving and mosaic work.
- Cypress and thuja
The properties are similar to juniper, but their wood is wider-grained and darker in tone. Used for small carving work.
- Oak –
It is characterized by high strength, hardness, resistance to rotting, bendability, and has a beautiful texture and color. Wood is widely used for making furniture and parquet. Oak veneer is used for cladding plywood and chipboard.
- Beech –
It has strong and hard wood; its strength is not inferior to oak. Beautiful texture on cuts; these decorative qualities are used when facing furniture with planed veneer.
- Birch –
It is characterized by high strength, uniform structure and color, medium density and hardness. It is mainly used for the manufacture of plywood and peeled chipboard veneer. It is easy to process and finish when etching for more valuable species. When steamed, it bends well.
- Disadvantages – it takes a long time to dry, it pricks easily, cracks and warps a lot. Wood Karelian birch
viscous and hard, easy to carpenter. It is highly valued in mosaic works and as an ornamental material.
- Ash –
wood similar to oak. Bends well after steaming.
Wood defects (slide No. 4)
Curling is the wavy arrangement of fibers, especially in the basal part of the tree. Most often observed in maple, oak, Karelian birch, and walnut. Such wood is difficult to process, but is valued in the manufacture of sliced veneer.
Curl is characteristic of local curvature of annual layers due to the influence of sprouts or trunk knots.
- Sprouting –
a defect in a section of wood resulting from mechanical damage to the fiber. This defect most often occurs due to the ingrowth of dead wood or bark into the sapwood.
- Cross-layered –
a defect expressed in the fact that the wood fibers are placed obliquely. Cross-grained wood is not used for manufacturing.
Wood color (slide No. 5)
Wood color is one of the characteristics by which one type of wood differs from another.
The wood of linden, pine, birch, maple, aspen is light, oak and ash are brown, walnut, teak are brownish.
The color shades of various species can be classified into main groups, where one color of wood will be predominant.
- Yellow – birch, spruce, linden, aspen, hornbeam, maple, fir, ash, barberry, Karelian birch.
- Brown – cedar, poplar, beech, larch, alder, pear, plum, chestnut.
- Brown – cherry, apple, apricot, walnut.
- Red – yew, mahogany.
- Pink – cherry laurel, plane tree.
- Orange – buckthorn.
- Purple – lilac, privet.
- Black – stained oak, ebony.
- Greenish – persimmon, pistachio.
Physical and mechanical properties of wood (slide No. 6)
- Hardness –
ability to resist processing by cutting tools. The lower part of the barrel has more hardness than the upper part.
- Durability –
the ability of wood to resist forces acting on it.
- Elasticity –
the ability of wood to change its shape under the influence of external forces and to return to its previous shape after the cessation of this influence.
- Plasticity –
the ability of wood to change (without destruction) its shape under pressure and retain it after the load is removed.
The conditional density of wood is the ratio of the minimum mass to the maximum volume of the sample. According to density at a humidity of 12%, tree species are divided into groups:
- Low density
- High Density
Humidity is a physical property of wood, characterized by the amount of moisture it contains.
Hygroscopicity is the ability of wood to absorb or release moisture.
Thermal conductivity – the ability of wood to conduct heat from one surface to the opposite. Coniferous species have lower density, and therefore lower thermal conductivity.
Sound conductivity – the ability of wood to conduct sound. Sound travels in different directions with unequal force. Thus, sound conductivity along fibers is 4-5 times higher than across them.
The high flammability of wood reduces the fire resistance of a building.
Lumber (slide No. 7)
– these are lumber with a thickness and width of more than 100 mm (up to 400×400 mm). According to the number of sawn sides, the beams can be two-edged, three-edged and four-edged.
– these are lumber with a thickness and width from 16 to 100 mm, the width of which is at least 2 times greater than the thickness. According to the nature of processing, they are unedged, single-edged and edged. The width of the boards is from 275 mm, length up to 6.5 m. The wide side of the boards is called the face, and the narrow side is the edge.
– these are lumber with a thickness of 50 to 100 mm, and a width of no more than double the thickness.
- Sliced and peeled veneer
serves as a material for facing and mosaic works. Obtained by planing or peeling wood:
– birch, alder, spruce, pine, beech and linden.
– walnut, ash, beech.
consists of several (three, five or more) glued layers of peeled veneer.
- Practical work.
To familiarize students with the appearance of the most common types of wood, samples of lumber, veneer, and plywood. Teach students to determine the type of wood and type of lumber by the appearance of the samples.
Option No. 2
Trees have played an important role in the life of mankind for many centuries. Thanks to trees and plants, we exist safely, as they release oxygen, which is needed for breathing, give us protection from the sun, and absorb carbon dioxide.
Even in primitive society, many tools were made of wood. This type of material is very popular in our time. People are increasingly using wood to build houses, bathhouses, foundations for large, serious structures and much more.
A tree is a large plant that reaches at least 5 meters in length and consists of roots, a trunk and a crown. Trees are coniferous, growing back to the Stone Age, and deciduous.
Coniferous species are typical for areas with colder climates, as they oxidize the soil to a greater extent. The main difference is that deciduous trees shed their leaves during the cold season to conserve energy, while conifers remain with needles throughout the year.
The most common types of trees in Russia
Some of the most common types of trees in Russia are: pine, the buds of which are actively used for the production of essential oils, spruce, common throughout almost the entire territory of our country, and larch, most often found in the Far East and in Siberia.
Purpose of roots
Supplying the entire plant with nutrients, water, and minerals is the main purpose of the roots. Please note that most often mushrooms grow directly under trees. It turns out that the whole point is that the mushrooms secrete into the roots of the tree some essential nutrients processed from the soil, which the tree itself cannot obtain.
Function of the crown and trunk of a tree
The crown is branches with leaves or needles, its main function is photosynthesis in the leaves and needles. The crown and roots are connected by the trunk, which stores the largest amount of nutrients; in addition, per day, approximately one cubic meter of water enters the crown through the trunk.
Wood in human life As is known, wood perfectly retains and retains heat, which is why it is actively used in construction. In addition, due to the huge amount of nutrients it contains, it is actively used in medicine.
Interesting facts about trees:
- In 2006, the evergreen sequoia was recognized as the tallest in the world, reaching a height of 115 meters.
- Some trees in Europe have passed the age limit in as many as 1000 years and grow up to 100 meters!
- The oldest tree in the world that was known to mankind is pine, which reached the age of 5100 years.
- There is an interesting fact about a tree called oak. It is known that it grows for 200 years, lives for 200 years and dies for another 200 years.
2nd, 3rd, 5th, 6th grade
Therefore, when choosing wood, it is necessary to take into account its resistance to decay and mechanical strength. Depending on environmental conditions, the durability of tree species varies. Thus, in non-structures unprotected from moisture, the following are poorly resistant: spruce, fir, birch, beech, maple; in damp places the following are highly resistant: larch, oak, alder; Pine and cedar are relatively stable under the same conditions.
The studies made it possible to establish that as a result of exposure to the environment in which the wood was kept for 70 years, the useful cross-section of wooden elements decreased by 15-20% due to damage to their outer part caused by the process of leaching and sliming of fresh wood water.
The strength of the wood of the outer layers (10-15 mm thick) turned out to be so low that it was easily crushed and destroyed by simple pressure with a fingernail. Microscopic analysis revealed complete destruction of the cells and the absence of any connection between them.
Outside the damaged outer layer, namely in the sapwood and in the core, no traces of destruction of the cell structure were found. Thus, the mechanical strength of the studied air-dried wood during compression, bending, and chipping was not lower than the norms allowed for healthy wood.
Salts of sodium, calcium, potassium, etc., found in sea water, have a greater effect on the wood of hydraulic structures than fresh river water. Research by Prof. S.I. Vanin showed that the strength of wood from piles that have been in water for about 30 years is 40-70% lower than that of normal wood that has not been in water.
The main type of wood used in the construction of hydraulic structures is pine. Oak and larch are used in structures that require high strength and resistance to decay. For the manufacture of small parts of dowels, dowels, wedges, linings, etc., oak, beech and other hardwoods are used. In terms of strength, wood must meet the following requirements.
The tensile strength for pine wood of grades 1 and 2 (when testing standard samples with a moisture content of 15%) must be no less than:
- when compressed along the fibers…………………. 300 kg/cm2
- when bending ………………………………………… 500 kg/cm2
- when cleaved along the grain…………. 50 kg/cm2
The calculated volumetric weight for freshly cut and raw wood is: for pine 800 kg/m3, for oak 1000 kg/m3.
Report No. 2
Types of wood and its use.
For more than a dozen centuries, humanity has learned to use or obtain many different materials and polymers for its needs. Fortresses were built from stones, quartz was heated to a glass state, clay could be used to create dishes by firing.
Brief concept about wood. Its properties.
This material has several definitions. Let’s take the easiest one to understand. At least, this is the concept used in everyday life. Wood is the tree underneath the bark, inside. This section of wood is formed from a conductive bundle.
It is also worth considering the properties inherent in wood. But there are quite a lot of them, and therefore we will take only the main ones. The most obvious property is that wood is a solid substance. And a fairly durable substance that can withstand decent loads. However, wood can be subject to deformation if force is applied.
How is wood used? And how many types of it are there?
In total, 16 types of wood are produced on the planet. For example, from spruce, pine or oak. Each species differs from each other in color shade and stripes. If we talk about the application, it is very extensive. The first thing that comes to any person’s mind is to use a tree for firewood.
- What everyday material is obtained from wood? Of course, paper. It turns out that all notebooks, textbooks, album sheets, books are all wood.
- Wood is widely used in the furniture industry. The same tables and chairs, cabinets, even the laminated flooring – all made of wood.
- The last thing I want to talk about is construction. Doors to an apartment can be made of wood, and window frames too. What can we talk about if you can still find houses made entirely of boards and logs!
5, 6, 7 grades, basic properties, structure, products. By technology
How this building material can be labeled
When purchasing wood, you need to pay attention to its compliance with European standards. All products sold must be CE marked.
Also, all construction wood is divided into four grades. Each variety is marked:
- Selected variety
– is marked in the form of one horizontal stripe, the number “0” or the letter “O”. It has no defects, knots or cracks. Rot and fungus are not allowed on it.
- 1st grade
—marked with one vertical stripe or dot, the number “1” or the letter “A”. Knots and small cracks can be seen on this wood.
- 2nd grade
– indicated by two vertical stripes or two dots, the number “2” or the letter “B”. Knots and cracks are more common in grade 2.
- 3rd grade
indicated by three vertical stripes or dots, the number “3” or the letter “C”. Such wood is susceptible to biological damage and fungus, waviness and structural defects. It is used for decking and sheathing.
If the marking of a selected or first grade contains the letter “C”, this indicates its suitability for shipbuilding. Skis are made from wood with the letter L.
All structural timber must be marked with permanent paint. Varieties have a specific purpose and a price corresponding to the quality. Knowing the difference between classes and types of wood, you can choose the right material, and sometimes save money.
This is how wood is marked in production:
The quality of timber must meet the requirements of GOST and additional requirements for load-bearing structures of hydraulic structures. No rot is allowed in any of the timber grades. For tensile and bending elements of load-bearing structures, 1st grade timber is used, and for compressed elements, 2nd grade timber.
Classification of the most popular tree species
Below are some samples for identifying deciduous tree species. However, it should be borne in mind that the color and texture of wood are influenced by the area where the tree grew, soil composition, climate and many other factors. First you need to determine what structure your wood has, and then relate it to one of the available options.
It should be borne in mind that with this approach it is possible to identify the wood in general terms by determining the generic name – for example, “birch”. You can analyze all types of wood available in your workshop or growing in your area. A tree identification guide can also be a good help.
Synopsis of a technology lesson in 5th grade “wood species, parts of wood. types of lumber”
Synopsis of a technology lesson in grade 5 “Species of wood, parts of wood. Types of lumber”
Lesson summary, grade 5
New words and concepts
Properties of wood: physical (density, moisture content) and mechanical (hardness, strength, elasticity); natural and artificial drying; stack, warping.
General information about wood” – presentation, report, project
What is obtained from wood?
All parts of wood have industrial use:
Wood is widely used for the construction of dwellings, for the manufacture of lumber, various wooden structures, and for the manufacture of dishes and furniture.
The resin is found in the trunk of coniferous trees. Turpentine and rosin are obtained from it. Rosin is used to produce soap, make varnishes, paints, linoleum, and esters. Turpentine is used in medicine and is used as a solvent for varnishes and paints.
Cellulose is obtained from wood, and this is the starting material for the production of paper, cotton wool, artificial fibers (viscose silk, staple), artificial furs and leather, photographs and films, varnishes, cellophane, gunpowder and other materials.
In folk medicine, a decoction of pine and spruce buds is widely used, which is prescribed internally for bronchitis and rheumatism. Essential oil is obtained from pine and fir needles, which is used as an aromatic and medicinal agent.
The healing power of oak. For treatment, young bark of branches and trunks, leaves and acorns of oak are used. Wood, bark, buds, leaves, inflorescences (fruits) of trees such as linden, aspen, and alder also have healing powers.
Determination of moisture content of wood samples
- Weigh three or four dry samples of wood of different species. Number them. Record the results in the table.
- Dip the samples in water and soak for 5-10 minutes.
- Remove and wipe the samples with a dry cloth. Weigh again. Record the results in the table.
- Calculate the moisture content of wood using the formula.
- Draw and record conclusions about the moisture absorption of wood of each species.
Determination of wood density
- Number the wood samples given by the teacher and calculate their volumes in cubic centimeters (cm 3
), multiplying the length by the width and the thickness in centimeters (cm). Write the data in the table.
- Weigh the samples and record the mass of each sample in grams (g). Write the data in the table.
- Using the formula, calculate the density of each sample in g/cm 3
and write it down in the table.
Practical work No. 2
Search for evidence
According to experts, it is possible to recognize the type of hardwood through a series of tests (see below). If one test does not provide a clue, you need to move on to another – and so on until a solution is found.
Botanists and dendrologists are usually quick to determine the type of tree. If they still have doubts, they look at the wood structures under a microscope. And even simple nature lovers, looking at a piece of wood through a magnifying glass, can usually tell what kind of species is in front of them (at least in a general approximation – it is oak, for example, or hickory).
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Testing your knowledge
- List the physical and mechanical properties of wood.
- What is called density, moisture, strength, hardness, elasticity?
- Why is wood dried?
- What types of wood drying do you know?
- How can you determine the moisture content of wood?
- Which piece will dry faster: thin or thick? Why?
Lesson topic: stages of creating wood products. grade: 5
Program section: Wood processing technology. Elements of mechanical engineering.
Lesson topic: Stages of creating wood products.
Labor task (labor object): drawing up a technological map.
Running time: 45 minutes
Lesson Learning Objectives: Students should master the following concepts:
1. Tell students about the stages of creating a wood product.
2. Introduce students to what “marriage” is.
3. Tell students what is called a technological transition.
4. Tell students what purposes technological maps serve.
5. Introduce students to the concept of “part” of an assembly unit.
Developmental goals of the lesson: students must master the following types of actions:
- Be able to divide the process of creating a wood product into stages.
- Be able to master the concept of “marriage”.
- Learn to comply with the technological transition.
- Be able to draw up technological maps.
- Be able to operate with the concept of “part” of an assembly unit.
Educational goals of the lesson: to convince students that:
- What is important is to learn the process of making a wood product in stages.
- That it is necessary to have an idea of what “marriage” is.
- That when creating a product it is necessary to observe a technological transition.
- That it is necessary to draw up technological maps.
- That it is important to be able to operate with the concept of “part” of an assembly unit.
Lesson type: Learning new material.
The main method of teaching a lesson: Explanatory and visual (reproductive) method.
– cutting tools;
Tishchenko A. T., Samorodsky P. S., Simonenko V. D., Shipitsyn N. P. Technology. Trial textbook for 5th grade boys / ed. V.D. Simonenko – Bryansk Pedagogical Publishing House. university. – Bryansk, 1995.
Checking students’ readiness for the lesson, marking those who are absent.
In order to make any product, it is necessary to perform a number of actions, that is, go through a number of stages.
It is necessary to think in advance about what materials the product will consist of, what tools are needed for this, on what equipment and workplace it is possible to manufacture the product.
Theme and objectives of the lesson.
So, the topic of today’s lesson is “Stages of creating wood products”, pay attention to the board where it is written.
Today we will study the stages of creating wood products and learn how to draw up a technological map.
Stage of updating knowledge.
Question: Who knows what “marriage” is?
Answer: Defects are unnecessary products made due to improper manufacturing of the product. Therefore, do not rush to start making the product right away.
Question: Who can say what is called a “blank”?
Answer: A blank is a material of a certain size from which a part is made.
Learning new material.
To begin manufacturing a product, first depict the product in the form of a technical drawing, sketch or drawing. Select a high-quality piece of wood of the required species. They mark the workpiece, checking the dimensions several times, then plan, saw, clean and finish it, turning it into a finished product.
Question: What is called an “assembly”?
Answer: Assembly is the joining of parts into a product.
If the product consists of several parts, then after manufacturing they must be adjusted to each other and connected to each other. The manufactured product must be checked for strength and tested. If any shortcomings are discovered, the reasons for their occurrence must be found and eliminated.
The sequence of actions for processing workpieces and assembling them into a product is described in special instructional and technological cards. Products may consist of one or several parts. Each part is made from one piece of material.
Question: Who can say what is called an “assembly unit”?
Answer: An assembly unit is the connection of parts into a product.
The product may consist of one or more assembly units. Parts are processed using working tools, either manually or on machines. Each part is manufactured according to its own technological process, which is part of the entire production process of transforming a workpiece into a part or product.
The technological process of manufacturing parts consists of a number of technological transitions (operations).
Question: What is called a “technological transition”?
Answer: A technological transition is a completed part of a technological process performed at one workplace.
For example, transitions will be: cutting out a workpiece on a carpentry bench, painting a workpiece in a paint room.
The manufacturing process is recorded in the form of a technological map, which indicates the sequence of transitions, a graphical representation of the changing workpiece and the tools and devices used.
Now let’s look at the technology for making a kitchen cutting board. Let’s take the simplest product to master the technique of drawing up a technological map.
Question: Guys, who knows where the creative work of making any product begins?
Answer: The creative work of making any product begins with the selection of a workpiece.
Question: What materials can a cutting board be made from?
Answer: The material for preparing a cutting board can be plywood or a board with a thickness of 10…12 mm, since the cutting board should be light and environmentally friendly. The contour of the product is placed on this blank according to the template.
Question: Does anyone know what the next step in making a cutting board is?
Answer: The next step is cutting out the outline of the product.
Then prick the center of the hole with an awl. Drill it out.
Question: What should be done during the finishing process when making a kitchen cutting board?
Answer: The final stage of this work is cleaning the product, rounding sharp edges and corners.
Guys, look at the technological map for making the kitchen cutting board shown in Table 1.
The stage of applying new knowledge, abilities, skills and methods of action.
- Carefully study the drawing of the part you want to make.
- Using table 1, develop a technological map for the manufacture of your part.
- Compare the completed routing with the routing developed for this part by your classmates.
Read and study §8. Page 38 – 40. Answer the questions at the end of the paragraph and develop a technological map for the manufacture of your part.
Summing up the lesson.
Guys, today we got acquainted with the stages of creating wood products and learned how to draw up a technological map.
Thank you for your attention…
Making a kitchen cutting board
|Item No.|| Follower-|
|Graphic image||Tools and accessories|
|1||Select a piece of board or plywood with a thickness of 10…12 and mark the outline of the product according to the template||Template, pencil|
|2||Cut out the outline of the product||Hacksaw carpentry workbench|
|3||Prick the center of the hole with an awl and drill a hole.||Awl, drill, brace or drill|
|4||Clean the product, round off sharp edges and corners||Workbench, sanding block, vice.|
Working conditions for wood in hydraulic structures
differ significantly from conditions in conventional above-ground structures. For many hydraulic structures, the humidity regime is constantly changing due to a natural or artificial decrease in the water level; The alternating moistening and drying of wooden elements that occurs during this process helps to create a favorable environment for their rotting.
V. summing up lessons
Today you became acquainted with wood as a structural material. We learned about the structure of wood and remembered different species. We became familiar with the various properties of wood. We knew what lumber was and where it was used. This knowledge will be useful to you when further studying wood processing technology, and for some it may be useful in everyday life.
ADVICE. If possible, these slides can be printed as posters or as handouts for students.