Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 8
Age: 15 years
Duration: 45 minutes
Subject: Wood Work
Curriculum Theme: Vocational Studies
Previous Lesson: Timber Conversion Characteristics and Market Sizes.
Topic: SEASONING OF TIMBER AND METHODS
Subject Matter: reasons for seasoning timber, natural seasoning, artificial seasoning, stacking practices

Specific Objectives

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

Cognitive Domain:

Define timber seasoning.
State at least three reasons for seasoning timber.
Differentiate between natural and artificial seasoning methods.
Explain the importance of proper stacking practices during seasoning.

Affective Domain:

Appreciate the importance of seasoning timber for durability.
Show interest in learning various timber seasoning techniques.

Psychomotor Domain:

Illustrate good timber stacking practices for natural seasoning.
Identify correctly seasoned timber samples.

Work cooperatively in groups to discuss seasoning methods.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology (JSS 1-3)
State Unified Scheme of Work for Senior Secondary Schools.
Wood Work for Senior Secondary Schools by E.A. Olaitan.
Basic Woodwork for Senior Secondary Schools by Oladele, A.A.

Instructional Materials

The teacher will teach this lesson with the aid of:

Charts showing different seasoning methods.
Posters illustrating timber stacking practices.
Samples of seasoned and unseasoned timber.
Whiteboard and markers.

Rationale for the Lesson

This lesson helps pupils understand why timber must be treated before use. Knowing about timber seasoning ensures that pupils can select and use durable wood for various projects, preventing issues like warping or decay in their wood work products and everyday items.

Prerequisite/Previous Knowledge

Pupils have basic knowledge of timber as a material used in construction and craft, and its general properties.

Lesson Content/Board Summary

SEASONING OF TIMBER AND METHODS

Definition of Timber Seasoning

Timber seasoning is the process of removing moisture or sap from freshly felled timber to reduce its moisture content to an acceptable level for use.

Reasons for Seasoning Timber

The following are reasons for seasoning timber:

To prevent shrinkage, warping, and twisting after the timber has been used.
To increase the strength and durability of the timber.
To make the timber lighter and easier to transport and work with.
To prevent fungal decay and insect attacks.
To improve the timber’s ability to hold paints, varnishes, and adhesives.
To reduce the likelihood of cracks forming.

Methods of Seasoning Timber

There are two main methods of seasoning timber:

Natural Seasoning (Air Seasoning)

Natural seasoning involves drying timber in the open air, allowing moisture to evaporate naturally. It is a slow process that can take several months to years, depending on the timber type and thickness.

Characteristics of natural seasoning include:

Timber is stacked in a well-ventilated area, protected from direct sunlight and rain.
Stickers (small wooden strips) are placed between layers of timber to allow air circulation.
The ends of the timber may be coated to prevent rapid drying and cracking.
It is less expensive but requires a longer time.

Artificial Seasoning

Artificial seasoning involves using controlled environmental conditions to speed up the drying process. It is faster than natural seasoning but more expensive.

Types of artificial seasoning include:

Kiln Seasoning: Timber is dried in a heated chamber (kiln) where temperature, humidity, and airflow are carefully controlled. This method is fast and allows for precise moisture content control.
Water Seasoning: Timber is submerged in flowing water for several weeks. This washes out the sap, which is then replaced by water. After removal, the timber is air-dried.
Chemical Seasoning: Timber is treated with hygroscopic chemicals (e.g., salt solutions) which draw moisture out of the wood. It helps to reduce shrinkage and checking.

Timber Stacking Practices for Natural Seasoning

Proper stacking is essential for efficient natural seasoning. The following practices are important:

Level Foundation: Stack timber on a firm, level foundation to prevent warping.
Airflow: Ensure adequate space between stacks and around individual pieces for free air circulation.
Stickers: Use uniform stickers (spacers) of the same thickness between layers to create air gaps. Align stickers vertically.
Protection: Protect the stack from direct sun and rain using a roof or cover, but allow sides to remain open for ventilation.
End Coating: Apply a moisture-resistant coating to the ends of planks to prevent rapid moisture loss and end-checking.
Stack Height: Keep stack height manageable for stability and air circulation.

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 observe some wooden items in the classroom (e.g., desks, chairs, doors). The teacher then asks what happens to wood if it is not properly prepared before use, guiding them to think about warping, cracking, or decay. This leads to the day’s topic.
Pupils’ Activity: Pupils observe the wooden items and respond to the teacher’s questions, sharing their observations and prior knowledge.
Learning Point: Pupils are introduced to the concept of timber preparation and its importance.

Step 2: Presentation of Definition

Time: 5 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher formally introduces the topic “Seasoning of Timber and Methods” and defines timber seasoning, writing the definition on the board. The teacher explains that it is about removing moisture from wood.
Pupils’ Activity: Pupils listen attentively, copy the definition from the board, and ask questions for clarification.
Learning Point: Pupils learn the definition of timber seasoning.

Step 3: Discussion of Reasons

Time: 8 minutes
Teaching Skill: Questioning/Elaboration
Teacher’s Activity: The teacher guides a discussion on why timber needs to be seasoned, prompting pupils to think about problems associated with using unseasoned timber. The teacher then lists and explains the key reasons for seasoning timber on the board.
Pupils’ Activity: Pupils contribute to the discussion, suggest reasons, and take notes as the teacher lists and explains.
Learning Point: Pupils understand the various benefits and importance of seasoning timber.

Step 4: Explanation of Natural Seasoning

Time: 8 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains natural seasoning (air seasoning) as one method of drying timber. The teacher describes the process, its advantages (cost-effective) and disadvantages (slow), and uses charts to illustrate how timber is stacked for natural seasoning.
Pupils’ Activity: Pupils listen, observe the charts, and note down the key points about natural seasoning.
Learning Point: Pupils learn about natural seasoning as a method and its basic principles.

Step 5: Explanation of Artificial Seasoning

Time: 8 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher introduces artificial seasoning as the second method, explaining that it is faster and more controlled. The teacher describes different types, such as kiln seasoning, water seasoning, and chemical seasoning, highlighting their characteristics and uses charts/pictures to illustrate. The teacher also contrasts it with natural seasoning.
Pupils’ Activity: Pupils listen, observe the visual aids, and take notes on the different artificial seasoning methods.
Learning Point: Pupils understand various artificial seasoning methods and their distinctions.

Step 6: Demonstration of Stacking

Time: 6 minutes
Teaching Skill: Demonstration/Visualisation
Teacher’s Activity: The teacher uses small wooden blocks or a diagram on the board to physically demonstrate or illustrate good stacking practices for natural seasoning. The teacher emphasizes the use of stickers, level foundation, and protection from elements, as outlined in the board summary.
Pupils’ Activity: Pupils observe the demonstration carefully, asking questions about specific stacking techniques and taking notes.
Learning Point: Pupils visualize and understand the practical aspects of proper timber stacking.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

Define timber seasoning.
State three reasons why timber is seasoned.
Differentiate between natural and artificial seasoning.
Mention two good stacking practices for timber during natural seasoning.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of seasoning timber for durable wood work. The teacher then assigns homework: “List five advantages of kiln seasoning over natural seasoning.”
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of the lesson.

Lesson Keywords

Seasoning – The process of removing moisture from timber.
Timber – Wood prepared for use in construction or carpentry.
Natural seasoning – Drying timber in the open air.
Artificial seasoning – Drying timber using controlled conditions like kilns.
Stacking – Arranging timber in an orderly pile for seasoning.
Kiln drying – A method of artificial seasoning using heated chambers.
Shrinkage – Reduction in timber size due to moisture loss.
Warping – Distortion or bending of timber.

Differentiation

For pupils who are visual learners, the teacher will use more charts, diagrams, and actual timber samples. Auditory learners will benefit from clear explanations and discussions. Kinesthetic learners will be encouraged to participate in the stacking demonstration or handle timber samples. Pupils requiring additional support will receive simplified explanations and one-on-one guidance, while advanced learners can research and present on specific chemical seasoning methods.

Note for teachers using this lesson plan

Teachers should adapt this lesson plan to suit the specific needs and context of their pupils and available resources. Practical demonstrations with actual timber or models are highly recommended to enhance understanding.