Lesson Notes By Weeks and Term v5 - Grade 7
Revision and consolidation of Grade 7 Technology topics – Week 8 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Revision and consolidation of Grade 7 Technology topics – Week 8 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Technology
Class: Grade 7
Term: Term 4
Week: 8
Theme: General lesson support
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
This week is dedicated to revising and consolidating the key Technology concepts covered throughout Grade
7. We'll be revisiting structures, processing, and mechanical systems with a particular focus on how these concepts are applied in everyday South African life. A strong understanding of these foundational concepts is crucial because Technology, at its core, is about solving problems and creating solutions. These skills are increasingly important in a rapidly developing South Africa, where innovative thinking and practical problem-solving are highly valued.
2.1 Structures: A structure is anything that can withstand forces and support a load. Structures are essential for building houses, bridges, and even the chairs we sit on. We can classify structures based on how they distribute loads and resist forces: Frame Structures: These structures have a skeleton or frame that supports the load. Think of a building under construction, where you can see the steel beams forming the frame. Another example is a bicycle frame. The frame distributes the load across its members (beams, columns, etc.) providing strength and stability.
Examples in South Africa: Eskom power pylons (frame structure made of steel), housing frames.
Shell Structures: These structures have a thin outer surface that supports the load. An egg is a great example of a shell structure. The curved shape makes it incredibly strong for its weight. Car bodies and some building designs also use shell structures. A corrugated iron roof is a good example of a shell structure in South African homes.
Examples in South Africa: Corrugated iron roofing, water tanks, and geodesic domes sometimes used in community centers.
Solid Structures: These structures are made from a solid piece of material and support the load throughout. A brick wall is a solid structure. A solid structure can also be molded, like a clay pot.
Examples in South Africa: Brick walls of houses, concrete dams.
Factors affecting structural strength: The shape, the material, and the way the load is distributed all influence the strength of a structure. Triangles are strong because they distribute forces evenly. Using stronger materials like steel will increase the load-bearing capacity. The location of supports is also crucial - supports too far apart may cause the structure to bend or break. 2.2 Systems (Input, Process, Output): A system is a group of interacting components working together to achieve a specific goal.
All systems have three basic parts: Input: What goes into the system (e.g., effort, energy, materials, information).
Process: What happens inside the system to transform the input (e.g., a series of actions, a chemical reaction).
Output: What comes out of the system as a result of the process (e.g., a product, a service, information).
Example 1: A Fan (Mechanical System)
Input: Electrical energy (from the wall socket)
Process: The electrical energy powers the motor, which turns the fan blades.
Output: Airflow/Cooling Example 2: A Toaster (Electrical System)
Input: Bread, Electrical energy (from the wall socket)
Process: The electrical energy heats the heating element, which toasts the bread.
Output: Toasted bread. 2.3 Simple Machines: Simple machines are basic devices that make work easier by changing the direction or magnitude of a force. They don't reduce the amount of work needed, but they reduce the effort required.
The six simple machines are: Lever: A rigid bar that pivots on a fixed point (fulcrum).
Examples: See-saw, crowbar, bottle opener.
Pulley: A grooved wheel with a rope or cable running along the groove.
Examples: Flagpole, crane, window blinds.
Wheel and Axle: A wheel attached to a smaller axle.
Examples: Car steering wheel, screwdriver, doorknob.
Inclined Plane: A sloping surface.
Examples: Ramp, staircase.
Wedge: A double inclined plane that is used to split objects or hold them in place.
Examples: Axe, knife, doorstop.
Screw: An inclined plane wrapped around a cylinder.
Examples: Screw, bolt, jar lid.
Mechanical Advantage (MA): The Mechanical Advantage (MA) tells us how much easier a simple machine makes work. MA = Load (Force you are trying to overcome) / Effort (Force you apply)
Example Calculation (Lever): A person uses a crowbar to lift a rock. The rock weighs 200N (Load). The person applies a force of 50N (Effort). What is the Mechanical Advantage? MA = 200N / 50N = 4 This means the crowbar makes the lifting force 4 times easier. 2.4 Sustainability in Technology: Sustainability in technology refers to designing and using technology in a way that minimizes its negative impact on the environment and society.
This includes: Using renewable resources: Employing materials that can be replenished naturally, like wood from sustainably managed forests or solar power.
Reducing waste: Designing products that are durable, repairable, and recyclable.
Conserving energy: Developing energy-efficient technologies and promoting responsible energy consumption.
Considering the social impact: Ensuring that technology benefits all members of society and does not exacerbate inequalities. In the South African context, sustainability is particularly important due to challenges like water scarcity, energy poverty, and environmental degradation. We can promote sustainable technology by using recycled materials in construction, developing water-saving irrigation systems, and promoting the use of renewable energy sources like solar panels in rural communities.