Lesson Notes By Weeks and Term v4 - JHS 2

Lesson Video

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Performance objectives

• Identify joining and assembling materials.
• List tools used for joining and assembling.
• Demonstrate the correct use of some tools.
• Explain the processes of joining and assembling.
• Evaluate different joining methods.

Lesson summary

This lesson introduces the fundamental concepts of joining and assembling. We will explore how different parts of products we use every day—from the desks we sit on and the clothes we wear to the burglar-proof bars on our windows—are put together. Understanding these processes is crucial not only for making new things but also for repairing broken items, saving money, and appreciating the work of local artisans like carpenters, welders, and tailors in our communities. This knowledge forms the basis of practical skills in many technical fields.

Lesson notes

A. What are Joining and Assembling? Joining: This is the process of putting two or more pieces of a material together to form a single unit. For example, using a nail to attach two pieces of wood. Assembling: This is the complete process of putting all the different parts of a product together in the correct sequence to create a finished item. For example, building a complete table involves joining the legs to the tabletop, adding braces, and ensuring everything is stable. Assembling is the bigger picture; joining is one of the key actions within it. B. Types of Joints

We can classify joints based on how easily they can be taken apart. Permanent Joints: These are joints that cannot be separated without damaging or destroying the materials or the fastener. Once it's done, it's meant to stay forever. Examples: Welding: Fusing two pieces of metal together using heat. (Think of a metal gate). Gluing: Using strong adhesives like wood glue (PVA) or epoxy resin (Araldite). (Think of a well-made wooden cabinet). Sewing: Using a thread to stitch fabrics together permanently. (Think of your school uniform). Temporary Joints: These joints are designed to be easily taken apart without damaging any of the components. This is useful for products that may need maintenance, repair, or disassembly. Examples: Bolts and Nuts: A bolt is threaded through holes in two parts and a nut is tightened to hold them together. (Think of the wheels on a car or trotro). Screws: A screw cuts its own thread into a material to hold it securely. They can be unscrewed easily. (Think of the hinges on a door or the back of a TV remote). Semi-Permanent Joints: These joints are not designed for easy disassembly, but they can be taken apart, though it might cause some minor damage to the material. Examples: Nails: A nail is hammered into wood. It can be removed with the claw of a hammer, but this often leaves a hole and can mark the wood. (Think of a simple wooden crate or a 'chop box'). Rivets: A rivet is a metal pin that is passed through two holes and then hammered to form a head on the other side, locking the pieces together. They are common on metal trunks. You have to drill or break the rivet to remove it. C. Identification of Joining Materials, Tools, and Equipment

Let's look at specific examples across different materials we use in Ghana.

| Material Being Joined | Joining Material (The Fastener) | Joining Tool / Equipment (What you use) | Type of Joint | Example Artefact | | :--- | :--- | :--- | :--- | :--- | | Wood | Nail (e.g., wire nail, clout nail) | Claw Hammer or Pin Hammer | Semi-permanent | Building a simple hen coop, making a wooden crate. | | Wood, Metal, Plastic| Screw (e.g., wood screw, self-tapping screw)| Screwdriver (Flat-head, Star/Phillips) or Drilling Machine | Temporary | Attaching hinges to a door, assembling flat-pack furniture. | | Wood | Wood Glue (e.g., PVA - Polyvinyl Acetate) | Glue Spreader, Brush, or direct from bottle; G-Clamps to hold it while drying. | Permanent | Making a fine cabinet, joining corners of a picture frame. | | Metal | Welding Rod (Electrode) | Arc Welding Machine (requires electricity, safety gear) | Permanent | Making burglar-proof windows, repairing a broken metal chair. | | Metal, Wood | Bolt and Nut | Spanner or Wrench (of the correct size) | Temporary | Assembling a metal bed frame, attaching a bench vice to a workbench. | | Thin Metal Sheets | Rivet | Rivet Gun (for pop rivets) or Hammer (for solid rivets) | Semi-permanent | Making a metal 'chop box', attaching handles to a metal pot. | | Fabric / Leather | Thread (e.g., cotton, polyester) | Hand Needle (for small repairs), Sewing Machine (for making clothes) | Permanent | Sewing a dress, mending a torn school uniform. | | Various (Plastic, Wood, Ceramic) | Adhesive/Super Glue | The tube/container itself | Permanent | Repairing a broken plastic toy, fixing a handle back onto a mug. |

Evaluation guide

• B8.3.3.1
• Demonstrate
• understanding of joining
• and assembling materials, tools and equipment used for making artefacts/