Class: Junior Secondary School 3 (JSS 3 / JS3)
Term: Third Term
Week: 10
Age: 14 years
Duration: 45 minutes
Subject: Basic Science and Technology
Curriculum Theme: Basic Science
Previous Lesson: Orthographic Projection: Definition.
Topic: SCALE AND SCALE DRAWING
Subject Matter: Definition, Types of Scale Drawing

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Define scale.
Define scale drawing.
Identify different types of scales.

Affective Domain:

Appreciate the importance of scale drawing in various fields.

Psychomotor Domain:

Draw simple objects to a given scale.

Collaborate with peers in practical scale drawing activities.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Science and Technology JSS 3
State Unified Scheme of Work for Basic Science and Technology JSS 3
MacMillan Basic Science and Technology for Junior Secondary Schools 3
https://www.youtube.com/watch?v=s20e-dJqX8U

Instructional Materials

The teacher will teach this lesson with the aid of:

Ruler
Pencil
Drawing paper
Sample scale drawings (maps, building plans)
Pictures and video clips showing real-life applications of scale drawing

Rationale for the Lesson

This lesson helps pupils understand how large or small objects can be represented accurately on paper. It enables them to apply concepts of ratio and proportion to practical situations, which is useful in fields like architecture, engineering, and geography.

Prerequisite/Previous Knowledge

Pupils have a basic understanding of measurement, ratios, and proportions.

Lesson Content/Board Summary

SCALE AND SCALE DRAWING

Definition of Scale

Scale is the ratio of a given length on a drawing or model to its corresponding actual length. It shows how much an object has been enlarged or reduced in its representation.

Definition of Scale Drawing

A scale drawing is a drawing of an object with its measurements in proportion to the actual object, but either reduced or enlarged. It accurately represents the dimensions and shape of the real object.

Types of Scales

The following are common ways to express scale:

Linear Scale (or Graphical Scale): This is a line divided into equal parts, each representing a certain unit of actual distance.
Ratio Scale (or Representative Fraction, RF): This is expressed as a fraction or ratio (e.g., 1:100 or 1/100), meaning one unit on the drawing represents 100 units in reality.
Verbal Scale (or Statement Scale): This is expressed in words (e.g., “1 cm represents 10 km”).

Importance/Uses of Scale Drawing

Scale drawing is important in many fields, including:

Architecture: For drawing building plans and models.
Engineering: For designing machines, bridges, and other structures.
Cartography: For creating maps that accurately represent geographical areas.
Fashion Design: For sketching clothing designs.
Science: For representing microscopic organisms or astronomical distances.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher displays a map or a building plan and asks pupils what they observe about its representation compared to real life. The teacher then introduces the topic: Scale and Scale Drawing.
Pupils’ Activity: Pupils observe the displayed materials and share their observations.
Learning Point: Pupils are introduced to the concept of scale representation.

Step 2: Definition of Scale

Time: 7 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher defines “scale” as the ratio of a length on a drawing to the actual length, providing simple examples like 1cm on paper = 10m in reality.
Pupils’ Activity: Pupils listen attentively and copy the definition into their notebooks.
Learning Point: Pupils understand what scale means.

Step 3: Definition of Scale Drawing

Time: 7 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher defines “scale drawing” as a drawing that represents an object accurately but at a different size, using the concept of scale. The teacher shows various examples like house plans, car designs, and maps.
Pupils’ Activity: Pupils listen, observe the examples, and write down the definition.
Learning Point: Pupils understand the meaning and purpose of scale drawing.

Step 4: Types of Scales

Time: 8 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains the different types of scales: linear, ratio (representative fraction), and verbal scales, giving examples for each.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils learn the different ways scale can be expressed.

Step 5: Demonstration and Practical Application

Time: 8 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher demonstrates how to use a scale to measure distances on a map or plan. The teacher also shows a short video clip illustrating the practical applications of scale drawing in architecture or engineering.
Pupils’ Activity: Pupils observe the demonstration and video clip, asking questions.
Learning Point: Pupils see real-world applications of scale drawing.

Step 6: Class Activity

Time: 5 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher gives pupils a simple task, such as drawing a rectangular classroom of actual dimensions 10m by 8m using a scale of 1cm to 2m.
Pupils’ Activity: Pupils attempt the simple scale drawing on their papers.
Learning Point: Pupils practice applying scale to draw an object.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

What is scale?
Define scale drawing.
Mention two types of scales.
State two importance of scale drawing.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarizing
Teacher’s Activity: The teacher summarizes the key points of the lesson and assigns homework: “Draw your bedroom using a scale of 1cm to 1m.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their learning and apply it at home.

Lesson Keywords

Scale – The ratio of a distance on a map or drawing to the corresponding distance on the ground.
Scale Drawing – A drawing that shows a real object with accurate sizes reduced or enlarged by a certain amount (called the scale).
Ratio – A comparison of two quantities by division.
Representative Fraction (RF) – A scale expressed as a ratio, e.g., 1:100.

Differentiation

For pupils who grasp the concept quickly, the teacher can provide more complex objects or different scales to draw. For pupils who need more support, the teacher can provide pre-drawn grids or simpler objects, offering one-on-one guidance during the practical activity.

Note for teachers using this lesson plan

Ensure that pupils understand the concept of ratio before introducing scale. Use clear, real-life examples to make the lesson relatable. Emphasize the importance of consistent units when working with scale. Encourage pupils to bring their own rulers and pencils for practical sessions.