Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 2nd Term
Week: 1
Age: 15 years
Duration: 45 minutes
Subject: Wood Work
Curriculum Theme: Vocational Studies
Previous Lesson: .
Topic: TIMBER PRESERVATION AND REASONS
Subject Matter: timber preservation, reasons for preserving timber, types of timber preservation

Specific Objectives

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

Cognitive Domain:

Define timber preservation.
State at least three reasons for preserving timber.
List three types of timber preservation methods.

Affective Domain:

Appreciate the importance of preserving timber for durability.
Show interest in adopting proper timber preservation techniques.

Psychomotor Domain:

Identify different timber preservatives.
Suggest appropriate preservation methods for various timber uses.

Discuss with peers the benefits of using preserved timber.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Senior Secondary Schools.
State Unified Scheme of Work for Wood Work SSS 1.
Basic Woodwork for Senior Secondary Schools by O. A. Adewale.

Instructional Materials

The teacher will teach this lesson with the aid of:

Samples of preserved timber.
Different types of timber preservatives (e.g., creosote, borax, wood guard).
Charts illustrating timber preservation methods.

Rationale for the Lesson

This lesson helps pupils understand how to protect timber from damage, making it last longer and perform better. Knowing about timber preservation is important for ensuring the longevity and economic value of wooden structures and items they might build or use.

Prerequisite/Previous Knowledge

Pupils have a basic understanding of timber and its uses from previous lessons.

Lesson Content/Board Summary

Timber Preservation and Reasons

Definition of Timber Preservation

Timber preservation is the process of treating wood to protect it from attack by fungi, insects, marine borers, and fire, thereby extending its useful life.

Reasons for Preserving Timber

The following are reasons why timber is preserved:

To protect timber from attack by fungi, which cause rot and decay.
To prevent damage from insects such as termites, wood borers, and beetles.
To increase the durability and service life of timber.
To maintain the strength and structural integrity of timber.
To enhance the aesthetic appearance of timber by preventing discoloration.
To reduce maintenance costs over time.
To make timber resistant to fire (fire retardant treatment).

Types of Timber Preservation

The following are types of timber preservation methods:

Chemical Preservation: Involves treating timber with chemical compounds. Examples include creosote, copper-chrome-arsenic (CCA), borax, and organic solvent preservatives.
Non-Chemical Preservation: Methods that do not rely on chemicals. Examples include:
- Seasoning/Drying: Reducing the moisture content of timber to below the level required for fungal growth.
- Design and Construction: Using appropriate designs to prevent moisture traps and ensure good ventilation.
- Natural Durability: Selecting timber species that are naturally resistant to decay and insect attack.
- Surface Coatings: Applying paints, varnishes, or sealants to create a physical barrier against moisture and pests.

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 recall some properties of timber. The teacher then asks what might happen to timber if it is left exposed to the elements for a long time without protection. This leads to the topic of preservation.
Pupils’ Activity: Pupils respond to questions and listen attentively.
Learning Point: Pupils are prepared for the lesson and connect new knowledge to previous understanding.

Step 2: Definition of Timber Preservation

Time: 10 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines timber preservation, explaining its purpose and importance. The teacher writes the definition on the board.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the meaning of timber preservation.

Step 3: Reasons for Preserving Timber

Time: 10 minutes
Teaching Skill: Listing/Elaboration
Teacher’s Activity: The teacher states and explains the various reasons why timber needs to be preserved, using examples where possible. The teacher lists these reasons on the board.
Pupils’ Activity: Pupils listen, contribute ideas, and copy the points from the board.
Learning Point: Pupils learn the importance and benefits of preserving timber.

Step 4: Types of Timber Preservation

Time: 10 minutes
Teaching Skill: Classification/Demonstration
Teacher’s Activity: The teacher discusses the main types of timber preservation (chemical and non-chemical), explaining specific methods under each. The teacher shows samples of preserved timber and different preservatives.
Pupils’ Activity: Pupils observe the samples, ask questions, and take notes.
Learning Point: Pupils identify and differentiate between various timber preservation methods.

Step 5: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

Define timber preservation.
State three reasons why timber should be preserved.
Mention two types of chemical timber preservatives.
List two non-chemical methods of preserving timber.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 6: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of timber preservation. The teacher assigns homework: Research on the environmental impact of different timber preservatives.
Pupils’ Activity: Pupils listen to the summary and copy the homework.
Learning Point: Pupils consolidate their learning and are given tasks for further study.

Lesson Keywords

Preservation – The act of keeping something in its original state or in good condition.
Timber – Wood prepared for use in building and carpentry.
Decay – The process of rotting or decomposing, typically caused by fungi.
Termites – Social insects that feed on wood and can cause significant damage to timber.
Creosote – A dark brown oil obtained from coal tar, used as a wood preservative.
Seasoning – The process of drying timber to reduce its moisture content.

Differentiation

For struggling learners, the teacher will provide simplified definitions and focus on core concepts, using more visual aids and direct questioning. For advanced learners, the teacher will encourage discussions on the economic implications of timber preservation and the environmental impact of various preservatives.

Note for teachers using this lesson plan

Teachers should ensure they have actual samples of preserved timber and various preservatives to make the lesson more practical and engaging. Safety precautions should be observed when handling chemical preservatives, and adequate ventilation should be ensured if demonstrating their properties.