Properties of Materials · SHS1 Manufacturing…

Lesson notes

Learning Objectives

Indicator: 1.1.2.LI.2 - Explain permeability, retentivity and reluctance as magnetic properties of materials.

By the end of the lesson, learners can:

Define permeability, retentivity and reluctance in their own words using correct technical terms.
Distinguish between materials that are easily magnetised (high permeability) and those that resist magnetisation (low permeability), giving local examples.
Explain how retentivity affects whether a material behaves as a permanent magnet or a temporary magnet.
Relate reluctance to the ease or difficulty with which magnetic lines of force pass through a material.
Justify the choice of a material for a specific manufacturing application based on its magnetic properties (e.g., transformer cores, electromagnets, fridge magnets).

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Curriculum details

Strand: Materials for Manufacturing (Strand 1)
Sub-strand: Properties of Materials (1.2)
Content standard: 1.1.2.CS.2 - Demonstrate knowledge in the mechanical properties of materials. 1.1.2.LO.1 Examine the physical and mechanical properties of materials.
Indicator: 1.1.2.LI.2 - Explain permeability, retentivity and reluctance as magnetic properties of materials.
Suggested placement: Semester 1, Week 9 (Week 9 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: NaCCA curriculum document, p. 30

Exemplars (from the NaCCA curriculum)

Research-Based Learning: In mixed-ability groups, learners research on the magnetic properties of materials such as permeability, retentivity and reluctance from the library or Internet and present their findings to the class to receive feedback.
Talk for Learning: In a class, discuss the relevance of the magnetic properties of materials to the manufacturing industries. Summarise views using concept maps or webbing.
Teaching and Learning Materials:
- Textbooks
- Internet access
- Library
- Library resource
- Internet access
- Audio-visuals
- Projectors
Assessment (1.1.2.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding; Level 3 Strategic reasoning.