Class: Junior Secondary School 3 (JSS3, JSS 3)
Term: 1st Term
Week: 3
Age: 14 years
Duration: 45 minutes
Subject: Basic Science And Technology
Curriculum Theme: Basic Technology
Previous Lesson: Processing of Wood: Growth and Felling of Trees
Topic: Processing of Wood (Part 2)
Subject Matter: Conversion, Seasoning

Specific Objectives

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

Cognitive Domain:
(a) Explain the processes involved in the conversion of wood.
(b) State the methods and importance of seasoning wood.
Affective Domain:
(a) Appreciate the importance of proper wood processing in building and furniture making.
Psychomotor Domain:
(a) Identify and sketch diagrams showing the stages of conversion and seasoning of wood.
Social Domain:
(a) Work cooperatively in groups to discuss the uses of well-seasoned and converted wood in the community.

Reference Materials

The following resources was used in planning this lesson:

9 Years Basic Education Curriculum
Lagos State Unified Scheme of work for Junior Secondary Schools
The Constructor – “Seasoning of Timber: Purpose, Types and Methods” (https://theconstructor.org/building/seasoning-of-timber/10747/)
Relevant Textbooks

Instructional Materials

The teacher will teach this lesson with the aid of:

Diagrams or charts showing stages of wood conversion and seasoning
Samples of rough logs, converted timber, and seasoned wood
Video or pictures of sawmills and drying kilns
Flash cards with key terms and definitions
Whiteboard and markers

Rationale for the Lesson

This lesson helps students understand how wood is prepared for use through conversion and seasoning, which ensures strength, durability, and prevention of decay.

Prerequisite/Previous Knowledge

Pupils have previously learned about the meaning and sources of wood, and can identify different types of wood used in carpentry and construction.

Lesson Content/Board Summary

Processing of Wood

Conversion of Wood

Conversion of wood refers to the process of cutting logs of wood into usable sizes and shapes for various purposes such as furniture, roofing, and building materials. It is usually done in sawmills using mechanical saws.

The following are the main methods of conversion of wood:

Through and Through (Plain) Sawing: The log is cut along its entire length into boards of equal thickness. It is fast and economical.
Quarter Sawing: The log is first divided into four quarters and then each quarter is sawn across the grain. This method gives stronger boards with beautiful grain patterns.
Tangential Sawing: The log is cut tangentially to the growth rings, producing wide boards.
Radial Sawing: The log is cut along its radius, giving boards of uniform pattern and high quality.

The importance of converting wood includes:

It makes wood easier to transport and handle.
It helps remove defects and irregular shapes in the log.
It allows wood to be cut into specific sizes for various uses.
It prepares wood for seasoning and finishing processes.

Seasoning of Wood

Seasoning of wood is the process of removing excess moisture or water from freshly cut wood to improve its strength, stability, and durability. Wood that is not seasoned properly can warp, crack, or decay easily.

The following are the methods of seasoning wood:

Air Seasoning: The wood is stacked in open air with spaces between the boards to allow free flow of air. It is simple and inexpensive but slow.
Kiln Seasoning: The wood is dried in a chamber (kiln) with controlled heat, humidity, and air circulation. It is faster and gives well-dried wood.
Water Seasoning: Logs are soaked in running water for some time, then dried in air. This helps remove sap and reduces the time of seasoning.
Solar Seasoning: Wood is placed under sunlight in covered sheds. It is a natural method suitable for small-scale drying.

The importance of seasoning wood includes:

It prevents wood from shrinking, cracking, or warping.
It makes wood lighter and easier to work with.
It increases the strength and durability of wood.
It prevents attack by insects and fungi.
It ensures smooth finishing during carpentry and joinery work.

Teaching Methods/Instructional Techniques:

Discussion, Lecture, Explanation, Demonstration, Question and Answer, Group Work, Visual Aids

Instructional Procedures

To deliver this lesson, the teacher will adopt the following steps:

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: Teacher asks pupils to recall how logs are obtained from trees and what they are used for. Then introduces the topic “Processing of Wood (Part 2)” by showing pictures of logs and processed timber.
Pupils’ Activity: Pupils respond and share their ideas about how wood is prepared for use.
Learning Point: Pupils gain awareness of the need to process wood before use.

Step 2: Conversion of Wood

Time: 10 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher explains the meaning of conversion of wood and describes the various methods using charts and illustrations.
Pupils’ Activity: Pupils listen, observe the charts, and identify each method of conversion.
Learning Point: Pupils understand the different methods of converting wood and their uses.

Step 3: Seasoning of Wood

Time: 10 minutes
Teaching Skill: Discussion
Teacher’s Activity: Teacher explains the meaning, methods, and importance of seasoning wood, using diagrams and examples of seasoned and unseasoned timber.
Pupils’ Activity: Pupils discuss the differences between wet and dry wood and give examples of where seasoned wood is used.
Learning Point: Pupils understand the purpose and benefits of seasoning wood.

Step 4: Demonstration of Seasoning and Conversion

Time: 10 minutes
Teaching Skill: Demonstration
Teacher’s Activity: Teacher displays samples of rough logs, converted timber, and seasoned wood for observation and comparison.
Pupils’ Activity: Pupils examine and touch the samples, noting differences in weight, texture, and appearance.
Learning Point: Pupils can distinguish between converted and seasoned wood.

Step 5: Note-Taking

Time: 5 minutes
Teaching Skill: Reinforcement
Teacher’s Activity: Teacher dictates or writes the summarized board notes for pupils to copy.
Pupils’ Activity: Pupils write down the lesson notes.
Learning Point: Pupils record key points on conversion and seasoning.

Step 6: Evaluation/Review

Time: 3 minutes
Teaching Skill: Questioning
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

What is meant by conversion of wood?
Mention two methods of conversion of wood.
What is seasoning of wood?
List three methods of seasoning wood.
State two importance of seasoning wood.
Pupils’ Activity: Pupils answer the questions orally.
Learning Point: Pupils demonstrate understanding of the lesson objectives.

Step 7: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: Teacher summarizes the lesson, emphasizing the importance of converting and seasoning wood before use.
Pupils’ Activity: Pupils listen attentively and ask relevant questions.
Learning Point: Pupils appreciate the importance of proper wood processing.

Lesson Keywords

Conversion – the process of cutting logs into usable timber
Seasoning – drying wood to remove excess moisture
Sawmill – place where logs are cut into boards
Kiln – chamber used for drying wood
Warping – bending or twisting of wood due to moisture

Differentiation

Teacher provides visual aids and real-life samples for slower learners, while faster learners can explain or sketch the stages of conversion and seasoning to the class.

Note for teachers using this lesson plan

Ensure safety when handling wood samples and tools. Encourage participation through group discussions and visual demonstrations for better understanding.