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WEEK: 6
TOPIC: Properties of Materials
SUB-TOPICS:
(i) Properties of Materials and Identification of wood, timber, structure of wood
(ii) Classification of hardwood and softwood.
Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)
Introduction
Materials are substances from which other things can be made. Basically, they can be classified into two: metallic and non-metallic. Furthermore, the metallic ones can be subdivided into ferrous and non-ferrous metals, while the non-metallic ones can be divided into natural and synthetic materials
Wood
One of the materials that is supplied by nature is wood. Wood is commonly used in some engineering manufacture because it is light, strong and can be worked upon easily.
Wood is a material obtained from trees. It is made up of cellulose and lignin each consisting of 60% and 28% respectively.
Identification of wood
Generally, wood has very good combination of colours to give it high decorative value. This makes it possible to identify some woods by their colour. Examples are:
| S/n | Trees | Colour identification |
| 1 | Iroko | Yellowish brown |
| 2 | Mahogany | Reddish brown |
| 3 | Afara | Pale-colour |
| 4 | Teak | Red-brown |
| 5 | Yew | Dark- green |
| 6 | Cotton- wood | Grayish white to light grayish brown |
| 7 | Hickory | Reddish brown |
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