Plane Geometry · SHS1 Design And Communication…

Lesson notes

Learning Objectives

Indicator: 1.2.1.LI.5 - Construct an Archimedean spiral as a locus.

By the end of the lesson, learners can:

Define a locus and explain how an Archimedean spiral is a special type of locus traced by a point moving at constant speed along a rotating line.
Identify the key elements of an Archimedean spiral: the centre, the constant distance between successive turns, and the number of convolutions (turns).
Construct an Archimedean spiral with 3 convolutions using drawing instruments, following the step-by-step method of dividing a circle and marking proportional points.
Draw a freehand Archimedean spiral that shows a constant gap between successive turns, demonstrating their grasp of the defining property.
Design a simple artefact, such as a spiral stair layout for a two-storey house, by applying the constructed spiral as a functional design element.

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Curriculum details

Strand: Geometry (Strand 2)
Sub-strand: Plane Geometry (2.1)
Content standard: 1.2.1.CS.1 - 1.2.1.CS.1 Apply the concept of plane geometry in designing. 1.2.1.LO.1 Use knowledge of plane geometry to draw plane geometrical shapes and design different artefacts based on plane geometrical figures.
Indicator: 1.2.1.LI.5 - Construct an Archimedean spiral as a locus.
Suggested placement: Semester 2, Week 5 (Week 25 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. 38

Exemplars (from the NaCCA curriculum)

Experiential learning, Problem -based learning:
1. With the aid of YouTube video, charts, cut shapes, school environment and drawing instruments, assist learners to draw an Archimedean spiral.
2. Use the concept of drawing Archimedean spiral to design a spiral stair for a two- story domestic house.

Assessment (1.2.1.AS.5). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding; Level 4 Extended critical thinking and reasoning.

Teaching and Learning Materials:
- Models
- Charts
- Reference books
- Drawing studio
- Drawing instruments
- Access to internet
- LCD Projector