JSS First Term Basic Technology Week 6 and 7 Wood
JSS First Term Basic Technology Week 6 and 7 Wood
In today’s class, we will be talking about Wood. Enjoy the class!
Wood
Wood is a fibrous and porous structural tissue of wood trees and other wood plans. This organic material made from natural cellulose fibres is found in their roots and stems, growing upward all the way to the tops of their canopy.
The main physical characteristic of wood fibres is their strong tension that is created both by its natural strength, and the way the fibres are embedded in a matrix that very effectively resists compression. Wood plays an important supporting role in a living tree.
Identification of wood
Woods are made from trees. There are 5 major parts of a tree. Namely:
Roots:
The roots search for mineral salts in the soil. They equally hold the tree firmly in the soil.
Stems or truck:
The stem supports the branches and exposes them to sunshine.
Branches:
They bear the fruits and leaves.
Barks:
Barks protects the growing part of the tree from weather animals and mechanical injury.
Leaves:
Leaves prepare plants food in the presence of sunlight. Plants respiration is carried out through the stomata.
Classification of wood
Woods are classified into two parts. They are the hardwood and the softwood. These various classes of woods have different characteristics.
The table below will best describe the two classes of woods
S/N HARDWOOD SOFTWOOD
1 Hardwood is called a deciduous tree. Softwood is called a coniferous tree.
2 Hardwood has broad leaves. Softwood has needle-like leaves.
3 Hardwood shed its leaves once every year. Softwood has evergreen leaves.
4 The seed is enclosed in cases. They have naked seeds
5 The heartwood of hardwood is heavy. The heartwood of softwood is light in weight.
6 The heartwood of hardwood is dark in colour. The heartwood of softwood has the same colour as sapwood.
7 Hardwood produce timber for furniture and other construction works. Softwood produces commercial softwood.
8 Hardwood is grown mostly in tropical regions. Example of hardwood is iroko tree Softwood is grown mostly in temperate regions. Example of softwood is whispering tree.
Week 7
Welcome to class!
In today’s class, we will be talking more about wood. Enjoy the class!
Properties and Uses of Wood
Properties of wood
The main physical properties of wood include colour, lustre, texture, macro-structure, odour, moisture, shrinkage, internal stresses, swelling, cracking, warping, density, sound – electro – thermal conductivity. Colour, shine, texture and macro-structure determine the appearance of wood.
Sensory characteristics include colour, lustre, odour, taste, texture, grain, figure.
Colour:
It covers a wide range — yellow, green, red, brown, black, and nearly pure white woods exist, but most woods are shades of white and brown. Variations may show on a single piece of wood, depending on colour differences between heartwood, sapwood, early-wood, late-wood, rays, and resin canals. Natural colour is subject to change by prolonged exposure to the atmosphere and by bleaching or dying. Some woods (for example, black locust, honey, and several tropical species) are fluorescent.
Natural lustre:
It is characteristic of some species (for example, spruce, ash, basswood, and poplar) and more prominent on radial surfaces.
Odour and taste are due to volatile substances contained in wood. Although difficult to describe, they are helpful distinguishing characteristics in some cases. The term texture describes the degree of uniformity of appearance of a wood surface, usually transverse.
Grain is often used synonymously with texture, as in coarse, fine, or even texture or grain, and also to denote direction of wood elements, whether straight, spiral, or wavy, for example. Grain sometimes is used in place of figure, as in silver grain in the oak. The term figure applies to natural designs or patterns of wood surfaces (normally radial or tangential).
Uses of wood
Home construction and Domestic constructions made out of wood were popular many years ago and are still widely used. Commonly, wood in home construction is used like the flooring, frames of the doors and windows and so on. There are a lot of types of wood that can be used in this sphere. For example Deodar (Cedrus deodara) and walnut wood (Juglans sp).
1. Fencing and decorating gardens:
It’s a very fashionable trend nowadays to decorate your home and garden. And when it comes to this, such material as wood is a perfect decision.
It is very popular for fencing as well.
2. Building:
Woods are used for building boats and lorry bodies.
They are also used for construction and furniture works.
Woods are also used in hospitals to produce clutches.
They are used to form tool handles.
