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Lesson the world in 2nd grade "A".

Topic: Trees of the forest. What does a person make from wood?

Lesson Objectives: creating conditions for the formation in younger schoolchildren of an idea about the trees of the forest, about the use of wood by humans.

Tasks:

Educational: introduce students to the natural materials from which various objects are made; cultivate caring attitude towards things and respect for people different professions; pay attention to acute environmental problem- deforestation.

Educational: cultivate a caring attitude towards things and respect for people of different professions; instill a love for nature native land and to all living things on earth.

develop cognitive interest in new information, encourage learning new things, and draw attention to an acute environmental problem - forest destruction.

Lesson type: learning new material.

Teaching methods : ICT, verbal, visual, practical

Basic method : problematic

Form of organization cognitive activity students : frontal, individual, group.

Equipment:multimedia projector, interactive whiteboard Smart Board computer, document camera,slides on the topic: “What is it made from?” audio recording with bird voices; textbook by N.F. Vinogradova “The world around us”: 2nd grade, part 2 , notebooks on printed basis, herbarium of trees of the Volgograd region, individual cards with tasks,a set of pictures in envelopes for group work,various wooden objects, pieces of wood.

During the classes

I. Organizing time.

Check it out guys

Is everything in place?

Is everything alright?

A book, pen and notebook?

Have you checked? Sit down!

Work hard!

T.M. Guys! Today we have an unusual lesson. You are probably surprised that we have the world around us on a schedule, and we also prepared for a technology lesson and invited a biology teacher. I present to you the teachers who will teach you this lesson.

E.V. I am a biology teacher. Guys, unusual discoveries await you in this lesson.

V.B. I'm a technology teacher. Amazing surprises.

T.M. Guys, During the lesson you will complete tasks and give complete answers.

E.V. . Listen carefully to the teachers and the answers of your comrades.

V.B . Help each other by completing practical tasks.

II. Updating basic knowledge.

- Guys, let's remember what we talked about in the last lesson?

About the forest, about the trees of the forest.

Slide number 2 on the topic: “Forest”

The house is open on all sides,
It is covered with a carved roof.
Come to green house -
You will see miracles in it.

T.M. Guys, tell me, do you know everything about trees?

Student: No!

T.M Do you think we need to expand our knowledge about the trees of the forest?

Student: Yes!

T.M Where should we start our lesson?

Studying: From planning.

T.M. What do we always do at the beginning of the lesson?

Study: We remember what we have learned.

T.M. In any lesson we learn something, we learn something, which means we will continue...

Studying : learn new things

Knowledge will not be strong if it is not...

Study: z strengthen

T.M. And also any work is required...

Studying: check and evaluate.

(A picture plan appears on the board).

T.M. Well, now let's get to work. I hope everything works out for us.

Look who came to visit us again.

Slide number 3.

Studying: Le-so-vi-chok! I invite you to play forest game"Not really".

T.M. Shall we play? Prepare your cards.

Individual work on cards “YES”, “NO”.

a) This tree is not afraid of frost, heat, drought. He needs a lot of light and sun.

A decoction of this tree is used to treat teeth and gums. This -pine ? +

b) If you pour boiling water over the dried flowers of this tree, you will get a very tasty, aromatic, medicinal tea for colds. The aromatic, light honey of this plant is also useful.

Is this a birch? (No, Linden).

c) A powerful trunk, thick branches on which hard leaves are located. The tree is long-lived. Many peoples considered this tree to be the most beautiful.

(Is this a poplar?) -, oak.

G) deciduous tree, which can reach 30 meters in height. The leaves sit on a long petiole, have a rounded shape and consist of five blades. The fruits of this tree are very interesting - they look like small helicopters. (Is this maple?) +

e) Coniferous tree, the age of which can reach up to 600 years. The leaves are modified into needles 3 cm long and can stay on the tree for 6 to 8 years. Sometimes this forest beauty decorates people's houses on New Year's holidays.

Is this pine? -, spruce.

T.M. WITH We played with Lesovich. What advice should we give him?

Studying: Be more careful and read more.

2. Group work using cards.

T.M. Guys, you know, trees don't like loneliness. They rarely grow apart from each other. Most often they gather in groups. To complete the next task, you also need to join groups. (Sit down in groups).

Group leaders will receivetasks. (Tasks are multi-level).

(I hold the envelopes like a fan).

T.M. Distribute responsibilities within the group.

Read the assignment and get to work. In the corner of the sheet, write a retrospective assessment of the work. (L )

(Children work. After completion, mark the mark with a colored pencil).

E. V . Checking on a document camera.

Checking group work.

Our group has prepared an interesting message about...

All the guys in our group helped find the right answers to the questions.

We were able to compose answers to the questions without errors.

I am very pleased with the work of the group.

( Groups report on their work using the screen).

Working on new material

E.V. . Do you want to know what interesting trees exist?

Student: Yes!

Slide No. (Teacher's story).

They live in hot countries. And you will learn about them in more detail when you start studying biology.

E.V. Guys, in our Volgograd region there are also interesting trees - long-livers. This is the famous poplar and oak.

Slide No.

E.V. Our exhibition presents books from which you can learn a lot of new and interesting things about the plants of the Volgograd region.

(Exhibition: Dictionaries, reference books, etc.)

To remember our lesson, 11th grade students give you booklets about plants of the Volgograd region.

(11th grade students distribute booklets).

III. State the topic and purpose of the lesson.

T.M. Guys, look around. Look and name objects whose ancestor is a tree.

What topic do you think we will work on in class today?

Studying: Explore what can be made from wood.

T.M. Where can we test our assumption?

Studying: In the textbook.

T.M . Open the textbook, page 48.

Read the topic of our lesson.

Did our guess match?

V.B .Guys! What is wood?

Children's answers.

Slide No.

V.B. Wood is the dense part of a tree located under the bark. (Dictionary).

Physical exercise.

The wind blows in our faces

The tree swayed.

The wind is quieter, quieter =

The tree is getting higher.

IV. Work on the topic of the lesson.

1.Working with the textbook. Reading text.

V.B- In the textbook, look at the drawing - diagram. Read about how man uses wood,remember what you learned new and tell me everything in one phrase,

(Children's answers).

V.B. And it is right.

Slide No.

V.B. Man began to use wood for his needs a long time ago. For many years in Rus', trees served people. Carpenters built huts, carpenters made cabinets, benches, cradles for children, bowls, spoons. Craftsmen carved toys from wood and wove bast shoes.

And now the trees are play a huge role in people's lives. There are many around us various items made of wood (various wooden objects are laid out on the table).

2. Practical work.

V.B. And now we will try to make something out of wood.

V.B. On your tables there are envelopes (a wooden plate, sandpaper, tree leaf template).

The teacher talks about artistic treatment products.

Now let's try to put woodworking into practice.

(The teacher initially demonstrates the task to the students and uses an example to show what their activities will be throughout practical work).

3.Work on the interactive whiteboard.

T.M. Let's compose a "Cinquain" based on the topic of the lesson.

What was the main word in the lesson?

Wood

Which? Hard, strong, viscous, soft.

What are they doing? They saw, chop, wash, plan.

Wood products: book, pipe, notebooks, cabinets, desks, pens, rolling pins, scissors, skis.

V. Homework.

T.M . At home you will complete the task of your choice:

1. Compile a tree passport. Textbook, p.50

2. Reading the text: pp. 48 – 49.

VI. Lesson summary.

1. Closing conversation. Reflection.

T.M. We thank all those who worked well in class today and were active.

If there were any difficulties or unresolved issues, do not worry, you are learning and everything will work out for you.

Raise your hands, who thinks they deserved an “A” in class? "4", "3"? (Student self-esteem.). I'm glad your mark matches mine. Well done!

When we are in the forest, we must always remember that our right is to use its gifts,

and it is our duty to protect it.

V.B. “To protect the earth and nature, you need to love it, to love it, you need to know it.”

Wood is a material made from shrubs and trees. It is used for the production of a wide variety of items and construction. It is easy to process, durable and heavy. The main advantage of wood, in comparison with other materials, is its ability to be renewed as a resource - with the right attitude towards surrounding nature people will always be able to use the wood they continually obtain.

The trunk of a growing tree becomes thicker every year and more wood is added to it, forming annual rings. The number of such rings on the cut of a tree trunk indicates its age. These rings add aesthetic appeal wood with its unique pattern of fiber texture. But there is also Negative consequences at wood growth. One of them is the property of wood splitting along the grain.

Wood preparation

Modern lumberjacks cut down the forest with powerful saws, cutting branches from the trunks in a matter of seconds special machines. The volume of the log is determined by the cubature. At sawmills, logs are cut into boards. Timber products require special drying before use. outdoors in stacks or in automatic dryers, where warm, dry air is supplied, the temperature and humidity of which are controlled. In dryers, wood becomes usable faster. If the wood is damp, products made from it will subsequently crack or curl.

But not all logs are sawn into boards. Some logs are rotated in special machines by very sharp blades, which cut the logs into thin plates called plywood. Plywood is most often made from laminated plywood, which is more durable and convenient to use than solid wood and less expensive. Chipboards are produced from forest sawing waste ( particle boards). They are often decorated with veneer, plywood or plastic and made from inexpensive furniture mass production or used as finishing material. Softwood is also used to make paper by grinding it into paper pulp. Even trees with thin trunks are suitable for this, which makes it possible in some countries to engage in special cultivation of forests for the needs of paper production. Such plantings are cut down before they reach the size of timber.

Some wood products are obtained by splitting wood using chemical processes. This is the fuel charcoal, an ingredient in some plastics and formulations road construction– lignin, used for the production of photographic film, paper and viscose – paper pulp.

Types of wood

When wood is used in construction or craft production, it is called timber. Timber products are usually divided into soft and hard.

Softwood - wood coniferous species trees (spruce, pine, cedar). They grow quickly and are specially grown artificially. Soft wood is easy to saw, drill and bend. It is necessary in construction, production of shipping boxes, paper and pressed wood.

Hardwood is made from the trunks of slow-growing tree species with broad leaves (oak, ash, birch, their tropical counterparts - mahogany and teak). Such wood is much more difficult to cut and shape, but it also hardly rots and is very durable. The structural pattern of such wood is often very beautiful. That's why hardwood is used to make expensive, fine furniture, musical instruments or special items such as boats or croquet sticks. Thin plywood Such wood is covered with slabs made from shavings of softwood trees. Tropical hardwood trees are becoming increasingly rare every year due to constant, merciless deforestation.

Joinery

Carpenters are those people who make a wide variety of objects from wood. They may make furniture or participate in the construction of houses. Most wooden parts are now made in factories using special machines (frames for windows, doors). But even today there is always work skillful hands carpenters

Skilled carpenters who make furniture as a work of art are called cabinetmakers. They are well aware of the technologies for assembling wooden products from individual fragments. The strength and beauty of the connections, which are achieved by the masterly precision of fitting the parts to each other. Correct gluing and screwing of parts together ensures additional strength and durability of the joints.

Various methods wood applications

High Quality wood (hard and soft) is used to make boards and other types of lumber.

Wood of lower quality is used to make plywood. Three or more sheets of plywood are glued together across the grain to form laminated plywood.

Waste from sawing and wood processing is crushed and mixed with sawdust and special resins and pressed to produce chipboard. Fiberboard is made from even smaller waste ( fibreboard).

Softwood is also crushed to make paper.

IN Ancient Rus' famous master carpenters who built wooden churches- masterpieces of wooden architecture without a single hammered nail or gluing. But some of them still stand to this day, striking with their beauty and grandeur!

Target: Introduce the natural materials from which various objects are made; form elementary representations about some production processes, starting from the extraction of raw materials in nature and ending with the receipt of the finished product; cultivate a caring attitude towards natural resources.

Planned results: Metasubject

Regulatory: be able to formulate learning task; understand the learning task of the lesson and strive to complete it ; formulate conclusions from the studied material; answer final questions; realize control and correction; evaluate results of your activities in the lesson. Cognitive:classify objects by the nature of the material, show different production chains in color; read textbook text; according to textbook drawings trace production chains, model them, make up story based on pictures, give other examples of use natural materials for the production of products. Communicative: participate in pair and group work. Agree with each other, accept the interlocutor’s position, show respect for other people’s opinions.

Subject: learn what natural materials people use to make products; learn to create simple production chains

Personal: take care of things; understand the need careful attitude to nature; respect people's work.

Educational materials: Textbook by A.A. Pleshakov “The World Around us”, workbook No. 1, computer, multimedia projector, screen, various objects made of clay, metal, wood, wool; cards - models. U students: signal flags, colored pencils (markers)

1. Organizational moment, emotional mood. (slide1)

The cheerful bell rang
Is everyone ready? All is ready?
We are not resting now,
We are starting to work.

2. Checking homework.

A) Individual tasks using cards. (2 children receive tasks)

Emphasize industrial products with one line and agricultural products with two.

1. Tomato, book, carrot, telephone, table lamp, potato, tractor, radish, onion, chair, iron, slippers.

2. Watermelon, cherry, chair, T-shirt, grapes, boots, coat, rocket, plum, school desk, pumpkin, cabbage, airplane, garlic, cucumber.

B) Game “True or False.”

Let's play the game “Is this true or false” (working with traffic light cards: if true, green, if not, red)

Is it true that the economy is the economic activity of people? (Yes)

Is it true that trade gives us bread, milk, and meat? (No)

Is it true that paper money was first used in China? (Yes)

Is it true that money is not made from wood these days? (Yes)

Is it true that clothes, shoes, furniture are produced in trade? (No)

Is it true that a painter, mason, plasterer, and crane operator work in construction? (Yes)

Is it true that we can purchase products and things in agriculture? (No)

Is it true that in order for us to drink a glass of milk in the morning, only agriculture and trade are working? (no, transport, industry)

Is it true that transport and industry specialists participate in the construction of a house along with the builders? (Yes)

Is it true that all sectors of the economy are connected to each other? (Yes)

Self-determination for activity

Look at the screen . (slide 2) The slide shows different objects.

(Shell, mittens, scissors, jug, ruler, spoon, scarf, mug, pencil)

Determine which one is “extra”? (shell)

Why? ( The shell was created by nature, and the rest was made by man)

What is the name of something made by human hands? ( Man-made world)

Practical work.

Divide the remaining items into groups based on material. (Divide objects into groups.)

All these items are familiar to you. Name them and explain what they do. What do all these items from the same group have in common? (Name the objects. Tell what they are for - made of clay (vase, pot, brick, clay whistle toy),

Made of wool (sweater, gloves, socks, scarf),

Made of metal (spoon, bowl, mug, scissors, metal construction set),

Made of wood (ruler, wooden spoon, nesting doll, notebook).

What will we talk about in class? (We will find out what and how people make different products from.)

Read the topic of the lesson in the textbook.

Formulate the educational tasks that we will set for ourselves? (we will talk about objects, find out what they are made of). Let's read about this in the textbook.

Working on the topic of the lesson.

Conversation “What is what?” (Work in groups)

Now let's talk about each group of items separately.

1. Wool (consider a group of wool items ) (slide 3)

We have determined that these items are made of wool. Where does wool come from?

(p. 111 of the textbook) Look at the pictures and tell us how woolen things are made.

1. Sheep shearing;

2. Making wool yarn, winding into bobbins;

3. Manufacturing of woolen fabric;

4. Drawing on fabric;

5. Manufacturing of clothing parts using patterns.

What new things have you learned about wool making?

How did you make this scarf? How did you get the different colors?

2. Tree (consider a group of wooden objects) (slide 4)

It is clear that the ruler and stand are made of wood. But how did the notebook end up in this group? How did our textbooks come into being? The guys who prepared the messages will help us figure this out.

a) Student speeches about paper making.

There are different types of paper. Where is it used?

The mill produces paper.

• The writer writes a work.
• Artist makes illustrations
• The publishing house prints books.
• Books appear in the store.

Children's performance.

Today, paper is made in factories where machines help people.

Machines get to work even when the future paper is growing in the forest. Electric saws cut and fell trees. Timber tractors carry logs to the river. Machines tie the logs into rafts, and the rafts float along the river to the workshop gate. Then other machines take over: a fast multi-saw machine cuts logs into logs; a debarking machine removes the bark from them; a chipper cuts logs into chips; the chips travel on a self-propelled track into the boiler. Wooden porridge is cooked in a special solution in a cauldron. When this porridge is ready, it becomes paper.

b) Collection display various types paper.

What is paper used for?

Is it easy to get the paper? How should we treat our notebooks and textbooks, because these are all cut down trees? And to grow an adult tree it takes at least 60 years.

They also make furniture, dishes, and toys from wood. (Show.)

6. Physical exercise

Now guess who we are talking about?.( The music sounds “Bu-ra-ti-no!”)(slide5)

Why do you think we remembered Pinocchio? (made of wood)

And from which fairy tale? (“Golden Key”. A. Tolstoy)

7. Conversation “Which is which?” (continuation)

For a long time in Rus', dishes and such wonderful toys were made from clay. (slide 6)

And how toys are made from clay, we learn from a fragment of the film .

(View a fragment of the film “The Inheritance of Grandfather Philemon.”)

A student's story about clay.

Clay is extracted from the quarry using excavators. In its raw form it is plastic. It is mixed with water to form a thick paste and then used to make dishes or toys. When the clay dries, it hardens and becomes very strong. The products are then fired in a kiln at a high temperature of 450°C. After firing, the clay becomes strong and will never become soft. The art of doing such things is called ceramics.

In ancient times, when there were no refrigerators, clay jugs were used to store cold water. The water remained cold as it seeped through the thin pores of the jug and evaporated, which helped keep the water cold.
The Chinese were wonderful potters. Made from special white clay porcelain. When fired, this clay becomes white. This cup is also made of clay.

It must be said that bricks, toys, and tiles are made from clay.

In the last group we had objects made of metal . (slide 7)

Student's story about iron production

Nobody makes iron, it is created by nature itself, like water, clay, sand... And people only mine this iron and turn it into cast iron and steel.

Iron is visible and invisible in the world - it is in sand (that’s why it is yellowish), and in reddish-brown clay, and in brown stone - flint. Iron is even dissolved in water.

Iron ores contain the most iron. It is from them that this most important metal is mined.

How is ore mined?

Here you can’t do without a huge, powerful steel digger, a small paper bag with an explosive charge and long wires. Miners will drill holes in the ground, place explosives in them, and send current through the wires. Shut your ears here. As soon as the explosion thunders, tons of earth and stones will fly into the air, scatter around, and the ore hidden underneath will be revealed. It happens that the ore itself has to be crushed by explosions. Finally, the explosions died down. A walking excavator gets to work. The excavator will scoop up ore with a scoop bucket, turn around, and a whole wagon or giant dump truck will be loaded. But the ore was brought to the plant. How to turn it into iron? A hot fire helps people here. In huge, like high-rise buildings, in the furnaces and blast furnaces the flames rage day and night. Here, to the very top of one of these domains, trolleys crawled along an inclined road. They will rise, tip over, pour the load into the oven - and down. Some trolleys contain ore, others contain white stone and limestone, and others contain fuel, dark gray spongy coke. It is like a pie, baked from the best coal ground into flour. Well, limestone helps the coke to draw out all the excess impurities from the ore.
Coke burns hot, but it cannot melt ore. To make it burn even hotter, you need to constantly fan the fire, you need air, hot, red-hot. That is why there are several more towers next to the blast furnace. It is in them that the air heats up. Powerful fans drive air currents through the pipes, continuously fanning a firestorm in the blast furnaces. The flame rages, the ore melts, settles, drops of cast iron metal gather in streams, streams... Cast iron is heavy, it flows to the bottom of the furnace, and all the excess that was in the ore rises and floats up in a bubbly fiery foam. This is slag.

Finally the master gives a signal: “The cast iron is ready!” We can release the melt.” A minute, another... and, scattering fountains of sparks, illuminating the sky with a fiery glow, liquid metal pours into a huge bucket. There are many buckets, each on wheels. There is a whole cast iron train standing on the rails. Once one ladle is filled, the next one will immediately fit under the stream. Where will the fire-breathing train go? His path is not far - to the neighboring workshop. Here the cast iron will be poured into molds. In them, the liquid metal will solidify and take the shape of the very mold into which it was poured. And you and I encounter cast iron every day. After all, ordinary frying pans, cast iron pots, radiators, grates into which streams run in the streets - all this is also cast from cast iron.

So, we have become acquainted with some materials from which a person can make the objects he needs. Now, to consolidate, let’s do the tasks in the notebook.

Consolidation (work in pairs):

Independent work using the “Workbook” pp. 39-40 No. 1,2

Show with arrows different color different production chains.

Write down what people can turn these materials into.

(Grain, mill, bread. Iron ore, factory, scissors, etc.)

And besides clay, wood, metal, what materials can various objects be made from? (Plastic, rubber, glass, etc.)

What should people pay attention to when mining in nature? various materials for making all kinds of products?

1) Extract no more materials than are required.

2) Spend sparingly.

3) Plant new trees.

4) Restore land at the site of quarries.

8. Lesson summary: (slide 8)

What question was answered in class?

Who now knows what dishes, clothes, and comfortable things can be made from?

To make various things, people mainly use materials found in nature. But their supply is not unlimited. Therefore, a person must treat natural resources with care.

9. Reflection (slide 9)

• I know that …
• I learned …
• I am satisfied…

10. Homework (slide 10)

Wood is a very popular material for making a variety of items. Wood products are made from forest products using machining, as well as gluing individual fragments. Wood is very durable and environmentally friendly material. In this regard, in a person’s life there are not only wooden crafts for everyday use, but also wooden building materials to create a beautiful and cozy home.

Drywall today can be called the most multifunctional building material. With it you can cover any surface in any room. To create a frame base for plasterboard sheets, you can use wooden or metal profiles. In this article we will tell you how to use a wooden profile for drywall.

Fiberboard boards are a wood-containing building material that is produced in the form of slabs. They are somewhat similar to fiberboard and chipboard, but they differ in a much more interesting set of performance qualities and properties. This explains their wider range of use in the construction industry.

Sheathing is chosen instead of plaster during the construction of block buildings. It will help to make the cottage unusual and elegant new material- wooden plank. In this article we will talk about what façade plank is and how the plank is installed.

SIP - Structural Insulated Panel. In Russian, there are two options for the name of this material - structural insulating panel or structured insulating panel. Sip panels are a type of multilayer building material that is highly resistant to sudden temperature fluctuations and has excellent performance parameters. Due to the special properties of the materials from which sip panels are created, they are not subject to rotting, freezing and almost do not absorb moisture.

We live in a time when innovative technologies make it possible to create analogues of natural materials and even replace them. Wood has been used for many centuries for finishing terraces and building ships. However, today the leading position in the market is occupied by composite decking boards, which are not inferior in characteristics to natural wood.

In the 21st century, the emergence of new technologies occurs almost every day, scientists are constantly developing new types floor coverings. Every year thousands of people make repairs and look for new ones. unique materials. Today, artificial parquet and massive board The engineered flooring board arrived.

Sawdust concrete is lightweight concrete, which necessarily contains cement, sawdust, mineralizers and sand. This material is environmentally friendly, lightweight, and increased level fire resistance, low thermal conductivity and high vapor permeability. It is used for the construction of monolithic buildings or for the creation of building blocks. It can also be used to build bearing structures. In regions where there are wood processing enterprises, the filler is sawdust. Such composite material in terms of its sanitary and hygienic characteristics, it can be called the most comfortable of all lightweight concretes for the construction of residential buildings.

Companies involved in the production of building materials are constantly introducing new developments. Progress does not stand still, and every year specialists increase and improve the range of products sold. More recently, the building materials market has been replenished with one more a unique product. In this article we will talk about tongue-and-groove moisture-resistant chipboard. She is very different high level resistance to moisture. And the unique design makes it possible to use it for various jobs.

Wooden lining today it is one of the the best materials for internal, and even exterior finishing, its demand is due to many reasons. It is both a decoration and protection from extraneous noise, and an excellent option for hiding communication lines. In addition, it is durable.

Wooden plinth is the finishing touch in floor or ceiling finishing works. This material serves as a kind of partition between the floor and the wall or the ceiling and the wall, and plays a decorative role in the design of the room. Skirting boards, which are made of wood, are high quality, practical and affordable. Installation of this material does not require special skills or abilities, even House master will cope with this task.

A properly laid tongue and groove floor board looks quite attractive and stylish. Floorboard You should choose something that is even and dry, otherwise the technician will encounter problems during the installation process, and the result will not be at all as expected. In this article we will talk about how to choose the right tongue and groove board, its advantages and disadvantages, as well as installation rules.

Wood today is radically different from what it used to look like. It looks less processed, but at the same time more fantastic. For example, 15 years ago no one thought about pouring wood liquid glass and enjoy a unique table in your home. Wood occupies one of the first places in the interior.

Today hundreds of millions coniferous trees create huge groves in different parts light, and people have used wood throughout the entire period of the existence of our civilization. Coniferous boards are an excellent material for construction and finishing. In this article we will talk about coniferous wood, its positive and negative qualities.

Bakelite moisture-resistant plywood - unique in its properties construction material. It is produced under the influence high temperature and pressure from birch or pine veneer and coated with an alcohol solution of phenol-formaldehyde resin (bakelite varnish). It differs from other types of plywood in its increased resistance to moisture, fire, chemicals, temperature changes.

Currently, there are many different floor coverings; there are three options for one parquet: piece parquet, panel parquet and parquet board. We are interested in what panel parquet is and how panel parquet is laid. We can say that panel and piece are one and the same; the difference between panel and panel is the presence of an original design and a larger size.

IN national economy wood is used very widely: in industrial and civil construction it is used for the manufacture of individual structural elements buildings and structures, as well as windows, doors, parquet, etc. Wood is a raw material for the production of cellulose, paper, cardboard, and ethyl alcohol. Chemical processing of wood produces rosin and turpentine; Tannins used in the leather industry are extracted from the bark of oak, willow and larch.

In shipbuilding, wood is used when laying ships on slipways and launching them into the water (keel blocks, slipways, runners, underbelly), for covering metal decks, for insulating and equipping provision storerooms, holds, cabins and other premises, for manufacturing wooden furniture, construction scaffolding, temporary ladders.

Wide Application wood explains it technical properties. With a relatively small mass, it has sufficient strength, is easy to process, glues well, and products made from it have good decorative qualities.

At the same time, wood also has a number of negative properties. When humidity changes, it swells, shrinks, cracks and warps. Natural wood materials susceptible to rotting and flammable. To a lesser extent, these disadvantages are characteristic of pressed wood, particle boards and fibreboards.

A growing tree consists of roots, trunk and crown. Roots absorb moisture and mineral nutrients from the soil and hold the tree in the soil. The branches and leaves of the tree form the crown. The so-called process of photosynthesis occurs in the leaves. They absorb from air environment carbon dioxide, which decomposes into carbon and oxygen. Oxygen from the leaves is released into the air, and carbon is influenced by sunlight, interaction with moisture and minerals dissolved in it forms various organic compounds necessary to nourish the tree, which spread throughout the inner layer of its bark.

The trunk supports the tree crown, stores moisture, and stores nutrients produced by leaves. It consists of pith, wood, cambium and bark (Fig. 1.1).

Rice. 1.1. Trunk structure
1 - bark; 2 - cambium; 3 - wood; 4 - core

The core, located in the center of the trunk, is loose soft tissue and occupies a small part of the trunk. Next is the wood, which occupies most of the trunk.

The cambium envelops the wood in a continuous ring. It consists of cells capable of dividing and growing.

The bark protects the tree from mechanical damage and from adverse influences environment. Inner layer bark (bast) serves to deposit nutrient reserves
substances produced in the leaves. The type of tree can be determined by the structure of the bark.

Wood - main technical material, the properties of which are inextricably linked with its structure. The macrostructure (structural elements) of wood is clearly visible on sections of the trunk with the naked eye. Thus, the annual layers, pith rays, core and sapwood are clearly visible in the sections.

The annual layers - concentric circles around the core - are clearly visible on the end section. On a radial section they are visible in the form of longitudinal lines, on a tangential section - in the form of arcuate curves. A living tree grows one annual layer every year. Growth comes from the cambium layer, so the closer the layer is to the pith, the older it is. By the number of annual layers on the end section of the butt part of the trunk, the age of the tree can be determined. The annual layer consists of early wood formed in spring period growth, and late, developing in summer period. The color of early wood is light. Late wood has a darker color and is distinguished by its high density and high mechanical qualities.

The medullary rays retain and also conduct moisture and nutrients horizontally between the annual layers. On the end section of the trunk (especially in oak, beech and maple), the medullary rays look like radially located narrow stripes, on the radial section - light or dark shiny stripes, and on the tangential section - dark strokes with pointed ends, located along the length of the trunk.

Some tree species have peripheral and central parts the trunk on the end and radial sections is different. Such tree species are called sound trees. Tree species whose trunks do not have this difference in color when cut are called sapwood.

The central, dark-colored part of the wood adjacent to the core is the core. It consists of dead wood, which is highly resistant to decay, as it contains a significant amount of resins and tannins.

Sapwood is a part of wood of early formation, consisting of young cells. In a growing tree, moisture moves through the sapwood with minerals dissolved in it. The width of the sapwood depends on the age and location of the tree. Pine and oak have wide sapwood. By mechanical properties sapwood is no different from core wood, but is less resistant to decay, as it easily absorbs moisture.

The microstructure of wood is visible only under a microscope. The main elements of wood are cells, wood fibers, vessels and tracheids.

Cells are thin, closed shells containing protoplasm and a nucleus. Cells reproduce by division: the nucleus is divided into two parts and two small ones are formed from one cell. As they grow, each of them also divides into two, etc. Living cells serve to transfer nutrients to each other and store reserves of these substances for the winter.