Lesson Notes By Weeks and Term v5 - Grade 7

Lesson Video

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Performance objectives

• Identify common basic materials and their products.
• Describe the purpose and use of common hand tools.
• Explain a simple processing technique, like cutting wood.
• Understand the importance of workshop safety.
• Know why different materials are used for different jobs.

Lesson summary

This week, we're diving into the fascinating world of processing basic materials. Processing refers to the actions we take to change raw materials into useful products.

Think about it: the wood used to make your desk wasn't just found in that shape! It had to be cut, shaped, and treated. Similarly, the metal in a bicycle frame went through a complex process of melting, shaping, and welding. Understanding these processes is essential because it allows us to create the things we need and use every day. In South Africa, processing industries are vital for job creation and economic growth, from food processing to manufacturing.

Lesson notes

Basic Materials: Basic materials are the raw substances from which useful products are made. In South Africa, we have abundant natural resources, making the processing of materials a crucial industry.

Some common basic materials include: Wood: Obtained from trees, wood is strong, relatively lightweight, and easy to work with. It's used for furniture, construction, tool handles, and many other products. Different types of wood have different properties. For example, pine is soft and easy to nail, while hardwood like oak is stronger and more durable.

Metal: Metals are strong, durable, and often conductive (able to carry electricity). Common metals include steel (used in construction, vehicles, and tools), aluminum (lightweight and corrosion-resistant, used in cans and aircraft), copper (excellent conductor, used in wiring), and iron (a key component of steel, used in construction).

Plastic: Plastics are synthetic (man-made) materials that can be molded into various shapes. They are lightweight, waterproof, and resistant to corrosion. Plastics are used for packaging, toys, furniture, and countless other applications. Different types of plastic have different properties; some are flexible, while others are rigid.

Textiles (Fabric): Textiles are made from natural fibers (like cotton, wool, and linen) or synthetic fibers (like polyester and nylon). They are flexible and used for clothing, upholstery, and other soft goods.

Clay: A natural earth material that hardens when heated. Used to make bricks, tiles, pottery, and other ceramic products.

Tools for Processing: Tools are essential for processing materials. Here are some common hand tools and their uses, with a focus on wood and metal: Saw: Used for cutting wood or metal. Different types of saws exist, each designed for specific purposes. A hand saw is used for cutting wood by hand. A hacksaw is specifically designed for cutting metal and has a fine-toothed blade. A coping saw is used for cutting curves in wood. Always saw away from your body, and use a clamp to secure the material you are cutting.* Hammer: Used for driving nails or shaping metal. Different types of hammers exist, such as the claw hammer (used for nailing and removing nails) and the ball-peen hammer (used for shaping metal). Always strike the nail squarely on the head to avoid bending it or hitting your fingers.* Screwdriver: Used for driving screws. Different types of screwdrivers exist, depending on the type of screw head (e.g., flathead, Phillips). Ensure the screwdriver head matches the screw head to avoid damaging the screw.* Pliers: Used for gripping, bending, or cutting wire or metal. Different types of pliers include long-nose pliers (for reaching into tight spaces) and cutting pliers (for cutting wire). Always grip the material firmly to avoid slipping.* File: Used for smoothing or shaping metal or wood. Different types of files exist, with varying degrees of coarseness. Always file in one direction only, applying pressure on the forward stroke.* Chisel: Used for shaping or removing wood or metal by striking it with a hammer. Always chisel away from your body, and use a mallet (a wooden hammer) to strike the chisel.* Sandpaper: Used to smooth wood or metal surfaces. Sandpaper comes in different grits (coarseness), with lower numbers indicating coarser sandpaper. Always sand with the grain of the wood to avoid scratching it.* Processing Techniques: Cutting Wood (Example) Let's break down the process of cutting a piece of wood with a hand saw: Safety First: Wear safety glasses to protect your eyes from sawdust. Secure the wood to a workbench using clamps.

Marking: Use a pencil and ruler to mark the line where you want to cut.

Starting the Cut: Place the saw blade on the marked line and use your thumb to guide the blade. Use short, gentle strokes to create a groove.

Cutting: Once the groove is established, use longer, smoother strokes to cut through the wood. Keep the saw blade aligned with the marked line. Apply gentle pressure on the downward stroke and release pressure on the upward stroke.

Finishing the Cut: As you approach the end of the cut, reduce the pressure to prevent splintering. Support the piece of wood that is being cut off to prevent it from breaking off prematurely.

Smoothing: Use sandpaper to smooth the cut edge.

Safety Precautions: Always wear safety glasses to protect your eyes from flying debris. Use the right tool for the job. Don't use a screwdriver as a chisel or a hammer as a wrench. Keep tools sharp and in good condition. Dull tools are more dangerous than sharp tools. Concentrate on what you are doing. Avoid distractions. Secure materials properly before working on them. Clamps and vises can help to hold materials in place. Keep your work area clean and organized. Guided Practice (With Solutions)

Question 1: Identify three different tools that could be used to shape a piece of wood. For each tool, describe its specific purpose and how it is used.