Simple Structures and… · JHS3 Career Technology

Lesson notes

Learning Objectives

Indicator: B9.4.1.1.2 - Describe the features and principles of operations of mechanisms

By the end of the lesson, learners can:

Identify and name at least five types of mechanisms (rack and pinion, cam, lever, linkage, pulley, crank, chain and sprocket) from charts, models, or real objects.
Describe the key features of each mechanism, stating its main parts and how those parts work together.
Explain the principle of operation of each mechanism using simple diagrams or labelled sketches.
State at least one advantage and one disadvantage of each mechanism type discussed in class.
Demonstrate how a selected mechanism works using a simple model made from local materials.

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Curriculum details

Strand: Technology (Strand 4)
Sub-strand: Simple Structures and Mechanisms, Electric and Electronic Systems (4.1)
Content standard: B9.4.1.1 - Demonstrate understanding of applications of mechanisms in project constructions
Indicator: B9.4.1.1.2 - Describe the features and principles of operations of mechanisms
Suggested placement: Term 2, Week 8 (Week 20 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Career Technology, Common Core Programme (JHS1-JHS3), 2023, p. 101
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

1. Use charts, models or real objects to describe the features of the various types of mechanisms.
2. Use simple diagrams to illustrate the operations of the various types of mechanisms.
E.g. Rack and pinion, cams, levers and linkages.
3. Discuss the advantages and disadvantages of the various types of mechanisms.
E.g., Pulley system:
- Advantages: No lubrication needed, quiet in operation
- Disadvantage: A slip can occur
4. Watch videos on the various types of mechanisms in operation and discuss in class.
E.g. The operations of the crank, cam, rack and pinion, chain and sprockets