Properties Of Materials: Wood JSS1 Basic Technology Lesson Note

MATERIALS AND PROCESSING-IDENTIFICATION OF WOOD

CONTENT

1.         Identification of Wood
2.         The Structure of Wood (internal)
3.         Major Parts of a Tree (external)
4.         Types of Wood
5.         Uses of Wood

IDENTIFICATION OF WOOD

The materials used in technology include wood, metals, ceramics, rubbers, and plastics. These materials come in different forms and each form performs a unique function. Wood is a hard fibrous substance that is chiefly composed of trees and bushes and is found beneath their bark.  

Wood is one of the materials used in furniture making and in building construction.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Different types of wood are identified by:

•             their color,
•             classification into soft and hardwoods
•             their properties e.g. hardwood has broad leaves while softwood has needle-like leaves.

THE INTERNAL STRUCTURE OF A WOOD

The internal structure of wood is made up of the following:

1.         Pith
2.         Xylem
3.         Phloem
4.         Cambium 
5.         Cork cambium
6.         Bark

EVALUATION QUESTIONS

1.         Mention the materials used in technology.
2.         Draw the structure of wood (internal).

There are trees all around us. Some are big and some are small.

MAJOR PARTS OF A TREE (EXTERNAL)

The major parts of a tree are:

1.         roots
2.         trunks (branches)
3.         leaves 
4.         flowers and 
5.         seeds

When a tree is allowed to remain for a long time, its trunk (stem) becomes bigger and bigger and the tree grows taller. The tree trunks are cut into wood or timber.                             

CLASSES OF WOOD

We have two classes of wood namely:

1.         HARDWOOD
2.         SOFT WOOD

PROPERTIES OF HARDWOOD

1.         It is dark in color.
2.         They are gotten from DECIDUOUS TREES.
3.         It has a complex cellular structure
4.         It is heavy.
5.         It has annual rings which are not visible.
6.         Hardwood trees have broad leaves.
7.         Examples include Iroko, Afara, Mahogany, Opepe, Omo etc.

Hardwood is used for furniture making and building construction.

PROPERTIES OF SOFTWOOD

1.         It has a lighter color than hardwood.
2.         It is not heavy.
3.         It is easy to work on.
4.         It is gotten from  CONIFEROUS TREE.
5.         Softwood trees have narrow and needle-like leaves.
6.         Softwood trees are usually evergreen because they do not shed their leaves in the dry season.
7.         Examples include spruce, fine, cedar, cypress e.t.c
8.         These are trees that bear naked seeds called (cones)
9.     These trees grow better in a temperate region (cold region of the world)

USES OF WOOD

Wood is used today in the following industries and processes:

1.         HOUSING: Wood is used for home furniture as doors, windows, and roofing.
2.         INDUSTRIAL BUILDING: Many industries are constructed using wood.
3.         JOINERY: Wood is used for making staircases in our buildings today.
4.         PACKAGING: Packaging technologists cannot do without wood for making crates, pallets, and packaging electronics equipment.
5.         FURNITURE; Chairs, bed, wardrobes, table book-cases etc.
6.         TRANSPORT: Railway, train-wagons, lorry-body.
7.         BRIDGES AND POLES: Most farm bridges and bridges across the roads in villages are made of wood. Some electric poles and railway sleepers are made of wood.
8.         PULP AND PAPER: Exercise books, textbooks, magazines e.t.c are made from pulp and paper derived from wood.
9.         MEDICINE: People who have their arms and legs amputated (cut off) are usually replaced by artificial limbs made from wood.
10. CLOTHING: Most heels and some soles shoes are made from wood e.g. the rayon stocking.
11. TOOL MAKING: Handles for hammers, pick axes, felling axes, screwdrivers, and many other tools are made from wood.

EVALUATION

1.         Differentiate between hard and soft wood.
2.         Mention five (5) uses of wood.