Lesson Notes By Weeks and Term v5 - Grade 8

Lesson Video

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Performance objectives

• Identify and explain simple machines.
• Calculate mechanical advantage (MA).
• Describe systems: input, process, and output.
• Explain technology's impact on society.
• Apply design principles to simple solutions.

Lesson summary

This week focuses on revising and consolidating key concepts covered throughout Term 1 and the start of Term 2 in Grade 8 Technology. Technology plays a crucial role in our daily lives, from the cellphones we use to communicate, to the bridges we cross, and even the food we eat. Understanding technological principles allows us to not only use these technologies effectively but also to critically evaluate their impact on our society and environment. In South Africa, technology can be used to address pressing issues like access to clean water, efficient farming practices, and affordable housing.

Lesson notes

2.1 Simple Machines Simple machines are basic mechanical devices that change the direction or magnitude of a force. They make work easier by reducing the amount of force needed to perform a task, although the distance over which the force is applied may increase.

Types of Simple Machines: Lever: A rigid bar that pivots around a fixed point called a fulcrum.

Examples: Seesaw, crowbar, bottle opener. Mechanical Advantage (MA) = Length of Effort Arm / Length of Load Arm Pulley: A wheel with a grooved rim around which a rope, chain, or belt passes.

Examples: Flagpole, crane. MA = Number of rope segments supporting the load (for block and tackle pulleys)* Inclined Plane: A flat surface set at an angle to the horizontal.

Examples: Ramp, stairs. MA = Length of Slope / Vertical Height Wedge: A triangular shape that is used to separate or split objects.

Examples: Axe, knife.

Screw: An inclined plane wrapped around a cylinder.

Examples: Screw, jar lid.

Wheel and Axle: A wheel attached to a central bar (axle) that rotates together.

Examples: Car wheel, doorknob.