Processing of Wood II

Subject: Basic Technology
Class: JSS 3
Term: First Term
Week: 3
Age: 12-15 years
Topic: Processing of Wood II
Sub-topic: Conversion and Seasoning
Duration: 60 minutes

Behavioural Objectives

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

1. Define wood conversion and its importance in wood processing.
2. Describe different methods of wood conversion.
3. Explain the seasoning process and its significance in preserving wood.
4. Identify the differences between air drying and kiln drying.

Keywords

• Conversion
• Seasoning
• Drying
• Timber
• Wood Products

Set Induction

Begin the lesson by showing a brief video demonstrating the conversion and seasoning processes of wood. This visual representation will help students understand the practical applications of the concepts.

Entry Behaviour

Students should have a basic understanding of wood processing stages covered in the previous lesson.

Learning Resources and Materials

• Whiteboard and markers
• Projector for video clip
• Printed handouts on wood conversion and seasoning
• Reference books (e.g., Lagos State Scheme of Work)

Building Background/Connection to Prior Knowledge

Discuss the previous lesson’s content on wood processing stages, focusing on the role of conversion and seasoning in making wood suitable for use.

Embedded Core Skills

• Critical thinking
• Practical skills in woodworking
• Communication
• Problem-solving

Learning Materials

• Projector
• Handouts detailing conversion and seasoning processes
• Infographics illustrating drying methods

Reference Books

• Lagos State Scheme of Work
• Basic Technology Curriculum for JSS
• Wood Science and Technology (Resource Book)

Instructional Materials

• Diagrams showing methods of wood conversion
• Samples of seasoned and unseasoned wood

Content

I. Conversion

1. Definition of Wood Conversion:
   • Conversion is the process of transforming raw logs into usable timber or lumber.
   • It involves cutting the logs into desired shapes and sizes for various applications.
2. Methods of Wood Conversion:
   • Sawmilling: The most common method, where logs are sawn into planks and boards.
   • Flitch Cutting: Cutting logs into thick slabs, preserving the grain patterns for aesthetic purposes.
   • Quarter Sawing: A method that produces boards with straight grain and reduces warping.
   • Plain Sawing: The most economical method but may lead to more warping and cupping of the wood.

II. Seasoning

1. Definition of Seasoning:
   • Seasoning is the process of drying wood to reduce its moisture content, making it more stable and durable.
2. Importance of Seasoning:
   • Prevents warping, cracking, and splitting of wood.
   • Reduces the risk of decay and insect infestation.
   • Improves the strength and durability of wood products.
3. Methods of Seasoning:
   • Air Drying:
     • Involves stacking wood in a well-ventilated area, allowing natural airflow to remove moisture.
     • Generally takes longer but is more energy-efficient.
   • Kiln Drying:
     • Uses controlled heat and humidity in a kiln to accelerate the drying process.
     • Results in more uniform moisture content and faster drying time.

Evaluation (Fill-in-the-Blank Questions)

1. The process of transforming raw logs into usable timber is called __________. (a) seasoning (b) conversion (c) drying (d) cutting
2. __________ is the most common method of wood conversion. (a) Flitch cutting (b) Sawmilling (c) Quarter sawing (d) Plain sawing
3. Seasoning helps to reduce the __________ content in wood. (a) air (b) moisture (c) weight (d) size
4. The main purpose of seasoning wood is to prevent __________. (a) color change (b) decay (c) growth (d) all of the above
5. __________ drying involves using natural airflow to remove moisture. (a) Kiln (b) Air (c) Fast (d) Wet
6. The method that produces boards with straight grain is __________. (a) quarter sawing (b) plain sawing (c) flitch cutting (d) none of the above
7. The process of cutting logs into slabs is called __________ cutting. (a) plain (b) sawmilling (c) flitch (d) seasoning
8. Proper seasoning can help prevent wood from __________. (a) being useful (b) becoming too heavy (c) warping (d) changing color
9. Kiln drying is faster than __________ drying. (a) air (b) water (c) sun (d) moisture
10. Sawmilling produces various sizes of __________. (a) logs (b) planks (c) leaves (d) trees
11. Seasoned wood is generally __________ than unseasoned wood. (a) weaker (b) heavier (c) more stable (d) softer
12. Flitch cutting preserves the __________ patterns of wood. (a) color (b) grain (c) thickness (d) age
13. The method that may lead to more warping is __________. (a) quarter sawing (b) plain sawing (c) flitch cutting (d) none of the above
14. The risk of insect infestation is reduced through __________. (a) seasoning (b) conversion (c) cutting (d) sawing
15. A well-seasoned piece of wood is more __________ for furniture making. (a) unstable (b) desirable (c) heavy (d) soft

Class Activity Discussion (FAQs)

1. What is wood conversion?
   Wood conversion is the process of changing raw logs into usable timber.
2. Why is conversion important?
   Conversion is important because it makes wood suitable for construction and furniture.
3. What are the common methods of wood conversion?
   Common methods include sawmilling, flitch cutting, quarter sawing, and plain sawing.
4. What does seasoning do to wood?
   Seasoning reduces the moisture content, preventing issues like warping and decay.
5. What is the difference between air drying and kiln drying?
   Air drying uses natural airflow, while kiln drying uses controlled heat to speed up drying.
6. How does seasoning affect the durability of wood?
   Seasoning improves wood’s strength and resistance to damage, making it last longer.
7. What are the risks of not seasoning wood?
   Unseasoned wood can warp, crack, or become infested with insects.
8. What type of wood is best for air drying?
   Most types of wood can be air dried, but it works best with hardwoods.
9. How long does air drying take compared to kiln drying?
   Air drying can take months, while kiln drying can take days to weeks.
10. Why is flitch cutting used in wood processing?
    Flitch cutting preserves the natural beauty of the wood grain for aesthetic purposes.
11. What types of wood products require seasoning?
    Furniture, flooring, and structural timber all require seasoning.
12. How can I tell if wood is properly seasoned?
    Properly seasoned wood will feel lighter and have a lower moisture content.
13. What happens to wood during the drying process?
    Moisture evaporates from the wood, making it more stable.
14. Is there any disadvantage to kiln drying?
    Kiln drying can sometimes lead to more checking (cracking) in some types of wood.
15. Why do different wood conversion methods matter?
    Different methods affect the quality and appearance of the final wood products.

Teacher’s Activities

1. Review the previous lesson by discussing the stages of wood processing.
2. Introduce the new topic using the video and defining key concepts.
3. Facilitate discussion and encourage student participation, correcting misconceptions as needed.

Learners’ Activities

1. Engage in discussions about conversion and seasoning processes.
2. Work in pairs to research different wood drying methods and present findings.
3. Complete the fill-in-the-blank questions and FAQs.

Evaluation Questions

1. Define wood conversion in your own words.
2. Why is it important to convert logs into timber?
3. What is the purpose of seasoning wood?
4. Explain the difference between air drying and kiln drying.
5. List and describe two methods of wood conversion.
6. How does improper seasoning affect wood products?
7. What is flitch cutting, and why is it used?
8. Discuss the advantages of kiln drying over air drying.
9. What are the signs of unseasoned wood?
10. How can proper wood conversion impact sustainability?

Conclusion

The teacher will circulate the classroom, marking students’ work and providing feedback on their understanding of wood conversion and seasoning processes. This helps reinforce their learning and clarify any remaining questions.