Lesson Note on Classification Of Timber: Types And Characteristics for SS1

Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: Second Term
Week: 3
Age: 15 years
Duration: 45 minutes
Subject: Furniture Making
Curriculum Theme: Trade
Previous Lesson: Timber Growth Structure And Classification: Cross Section Of A Tree.
Topic: Classification Of Timber
Subject Matter: Timber tree classification, Characteristics of timber classes, Uses of timber types

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Define timber.
• Classify timber into its main categories.
• State at least three characteristics of hardwood and softwood.
• List at least two uses for different timber types.

Affective Domain:

• Appreciate the importance of proper timber classification in furniture making.
• Value the selection of appropriate timber for specific tasks.

Psychomotor Domain:

• Identify samples of hardwood and softwood.
• Differentiate between hardwood and softwood based on physical characteristics.

Social Domain:

• Participate actively in discussions about timber types.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum for Basic Technology.
• State Unified Scheme of Work for Furniture Making SSS 1.
• F.N. Nwokoro. (2010). Basic Technology for Senior Secondary Schools 1-3. Learn Africa Plc.

Instructional Materials

The teacher will teach this lesson with the aid of:

• Samples of hardwood (e.g., Iroko, Mahogany)
• Samples of softwood (e.g., Pine, Cedar)
• Charts showing different timber trees and their properties.
• Whiteboard and markers.

Rationale for the Lesson

Understanding timber classification is important for pupils to select the correct type of wood for various construction and furniture making projects. This knowledge helps them to appreciate why different woods are used for different purposes, leading to better project outcomes and material efficiency.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of wood as a raw material and its general use in construction and craft work.

Lesson Content/Board Summary

Classification of Timber

Definition of Timber

Timber refers to wood in various stages of processing, from standing trees to felled logs, and sawn lumber ready for use in construction, furniture making, or other purposes.

Timber Tree Classification

Timber trees are generally classified into two main categories based on their botanical characteristics and properties:

• Hardwoods: These come from deciduous trees, which are broad-leaved trees that typically shed their leaves annually. Examples include Iroko, Mahogany, Teak, Obeche, Oak, and Walnut.
• Softwoods: These come from coniferous trees, which are typically evergreen trees with needle-like leaves and cones. Examples include Pine, Cedar, Spruce, Fir, and Redwood.

Characteristics of Timber Classes

Hardwoods and softwoods have distinct characteristics that influence their uses:

Characteristics of Hardwood:

• They are generally denser and heavier than softwoods.
• They are more durable and resistant to wear and tear.
• They grow slower, making them more expensive.
• They have complex pore structures, often resulting in attractive grain patterns.
• They are generally more difficult to work with due to their hardness.

Characteristics of Softwood:

• They are generally less dense and lighter than hardwoods.
• They are softer and less durable compared to hardwoods.
• They grow faster, making them more economical.
• They have simpler pore structures and a more uniform texture.
• They are generally easier to work with using hand and power tools.

Uses of Timber Types

The choice of timber depends on its properties and the intended application:

• Uses of Hardwood:
  • High-quality furniture (e.g., chairs, tables, cabinets)
  • Flooring and decking
  • Tool handles and sporting equipment
  • Decorative items and carvings
• Uses of Softwood:
  • General construction (e.g., framing, roofing)
  • Plywood and particleboard manufacturing
  • Paper production
  • Temporary structures and scaffolding
  • Cheaper furniture and crates

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to identify different wooden items in the classroom (e.g., desk, chair, door frame). The teacher then asks what they think makes these wooden items different in appearance or feel.
Pupils’ Activity: Pupils respond by identifying items and sharing their observations about the wood.
Learning Point: Pupils are engaged and begin to think about the variety of wood types.

Step 2: Definition of Timber

Time: 5 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines timber and explains its importance as a raw material in furniture making and construction. The definition is written on the board.
Pupils’ Activity: Pupils listen, take notes, and ask clarifying questions.
Learning Point: Pupils understand the basic meaning of timber.

Step 3: Timber Tree Classification

Time: 10 minutes
Teaching Skill: Classification/Demonstration
Teacher’s Activity: The teacher introduces the two main classes of timber: hardwood and softwood. The teacher uses the provided samples to demonstrate the differences, explaining that hardwoods come from broad-leaved trees and softwoods from needle-leaved trees. The teacher writes the classification on the board.
Pupils’ Activity: Pupils observe the samples, feel the texture, and listen to the explanations. They ask questions about the examples.
Learning Point: Pupils learn the two main categories of timber and their botanical origins.

Step 4: Characteristics of Hardwood

Time: 7 minutes
Teaching Skill: Description/Comparison
Teacher’s Activity: The teacher discusses and lists the key characteristics of hardwoods, such as density, durability, growth rate, cost, and workability. The teacher points out these features on the hardwood samples.
Pupils’ Activity: Pupils listen, observe, and note down the characteristics. They may touch the samples to feel the hardness.
Learning Point: Pupils understand the specific properties that define hardwoods.

Step 5: Characteristics of Softwood

Time: 7 minutes
Teaching Skill: Description/Comparison
Teacher’s Activity: The teacher discusses and lists the key characteristics of softwoods, contrasting them with hardwoods (e.g., less dense, softer, faster growth, cheaper, easier to work). The teacher points out these features on the softwood samples.
Pupils’ Activity: Pupils listen, observe, and note down the characteristics, comparing them with hardwoods.
Learning Point: Pupils understand the specific properties that define softwoods and can differentiate them from hardwoods.

Step 6: Uses of Timber Types

Time: 6 minutes
Teaching Skill: Application/Examples
Teacher’s Activity: The teacher explains how the characteristics of each timber class dictate their uses. The teacher provides examples of common applications for both hardwood and softwood, relating them to furniture making and construction. The uses are listed on the board.
Pupils’ Activity: Pupils listen, take notes, and contribute examples of timber uses they know.
Learning Point: Pupils connect timber properties to practical applications.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What is timber?
2. Mention the two main classifications of timber.
3. State two characteristics of hardwood.
4. List two uses of softwood.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the importance of knowing different timber types. The teacher then gives homework: “Research and bring two more examples of hardwood and two more examples of softwood found in Nigeria.”
Pupils’ Activity: Pupils listen to the summary and copy down the homework assignment.
Learning Point: Pupils consolidate their understanding and are prompted for further research.

Lesson Keywords

• Timber – Wood that has been prepared for use in building and carpentry.
• Hardwood – Wood from deciduous trees (broad-leaved trees that shed leaves annually).
• Softwood – Wood from coniferous trees (evergreen trees with needle-like leaves and cones).
• Deciduous – Trees that shed their leaves annually.
• Coniferous – Trees that bear cones and have needle-like or scale-like leaves, typically evergreen.

Differentiation

For pupils who grasp concepts quickly, the teacher can encourage them to research specific properties like wood grain patterns or moisture content. For pupils needing more support, the teacher will provide additional visual aids and allow more time for hands-on examination of timber samples, reinforcing the core distinctions between hardwood and softwood.

Note for teachers using this lesson plan

Ensure a variety of timber samples are available for pupils to touch and observe, as tactile learning is very effective for this topic. Encourage pupils to relate the lesson to local timber types and their common uses in their community. Safety precautions should be observed when handling wood samples, especially if they have rough edges.