Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 4
Age: 15 years
Duration: 45 minutes
Subject: Technical Drawing
Curriculum Theme: Technical Drawing
Previous Lesson: Safe Working Habits in the Drawing Studio.
Topic: LINES AND LINE WORK.
Subject Matter: types of lines and their uses, thin continuous line for projection construction and dimension, thick continuous line for outlines, thin long chain line for centre lines, short dashes for hidden details, drawing parallel lines, drawing inclined lines using tee square and set squares.

Specific Objectives

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

Cognitive Domain:

Define various types of lines used in technical drawing.
State the specific uses of at least four types of lines.
Identify the instruments used for drawing parallel and inclined lines.

Affective Domain:

Appreciate the importance of correct line work in technical drawing.
Show interest in learning and applying standard drawing practices.

Psychomotor Domain:

Draw different types of lines accurately according to their specifications.
Construct parallel lines using a tee square and set squares.
Construct inclined lines at specified angles using a tee square and set squares.

Work independently to produce accurate line work.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Technical Drawing.
State Unified Scheme of Work for Technical Drawing SSS 1.
Nduka, O. (2018). Comprehensive Technical Drawing for Senior Secondary Schools. A. Johnson Publishers.

Instructional Materials

The teacher will teach this lesson with the aid of:

Tee square
Set squares (30/60 and 45 degrees)
Straight edge
Compasses
Pencils (HB, 2H)
Drawing board
Drawing paper
Examples of technical drawings showing different line types.

Rationale for the Lesson

This lesson helps pupils understand the fundamental language of technical drawing, which is line work. Correct use of lines is important for clear communication and interpretation of engineering and architectural drawings in daily life.

Prerequisite/Previous Knowledge

Pupils should have a basic understanding of drawing instruments and how to hold a pencil correctly for drawing.

Lesson Content/Board Summary

LINES AND LINE WORK

Types of Lines and Their Uses

Lines are the basic elements of technical drawing. Each type of line has a specific meaning and use.

The following are common types of lines and their uses:

Thin Continuous Line: Used for projection lines, construction lines, dimension lines, extension lines, leader lines, and hatching.
Thick Continuous Line: Used for visible outlines, visible edges, and main object lines.
Thin Long Chain Line: Used for centre lines, axes of symmetry, and paths of motion.
Short Dashes (Hidden Line): Used for hidden details, invisible edges, and features that are not directly visible.

Drawing Parallel Lines

Parallel lines are lines that are equidistant apart and never meet.

Ways to draw parallel lines using a tee square and set squares:

Place the tee square firmly against the drawing board’s edge.
Place a set square against the edge of the tee square.
Draw a line along one edge of the set square.
Slide the set square along the tee square and draw another line parallel to the first.

Drawing Inclined Lines

Inclined lines are lines drawn at an angle to the horizontal or vertical.

Ways to draw inclined lines using a tee square and set squares:

Place the tee square firmly against the drawing board’s edge.
Place a set square (e.g., 30/60 degrees or 45 degrees) against the edge of the tee square.
Draw a line along the desired angled edge of the set square (e.g., 30°, 45°, 60°).
For other angles, use combinations of set squares or a protractor with the tee square.

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 greets the pupils, reviews the previous lesson briefly, and then introduces the new topic, “Lines and Line Work,” by asking pupils about the importance of different types of lines in everyday drawings.
Pupils’ Activity: Pupils respond to greetings and questions, and listen attentively to the introduction.
Learning Point: Pupils connect the new lesson to their prior knowledge and daily experiences.

Step 2: Explanation of Types of Lines and Their Uses

Time: 10 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher displays examples of drawings showing different types of lines. The teacher explains each line type (thin continuous, thick continuous, thin long chain, short dashes) and their specific uses, as outlined in the board summary.
Pupils’ Activity: Pupils observe the displayed drawings, listen to the explanations, and ask questions for clarity.
Learning Point: Pupils understand the names and functions of various lines in technical drawing.

Step 3: Demonstration of Drawing Different Line Types

Time: 10 minutes
Teaching Skill: Demonstration/Modelling
Teacher’s Activity: The teacher demonstrates on the drawing board how to draw each type of line correctly, emphasizing line thickness and consistency, using appropriate pencils.
Pupils’ Activity: Pupils observe the demonstration carefully, noting the techniques for drawing each line type.
Learning Point: Pupils learn the practical skills required to draw different types of lines.

Step 4: Demonstration of Drawing Parallel Lines

Time: 5 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher demonstrates how to draw parallel lines using a tee square and a set square, explaining the process clearly.
Pupils’ Activity: Pupils observe the demonstration of drawing parallel lines.
Learning Point: Pupils understand the method for constructing parallel lines.

Step 5: Demonstration of Drawing Inclined Lines

Time: 5 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher demonstrates how to draw inclined lines at specific angles (e.g., 30°, 45°, 60°) using a tee square and set squares.
Pupils’ Activity: Pupils observe the demonstration of drawing inclined lines.
Learning Point: Pupils understand the method for constructing inclined lines at various angles.

Step 6: Class Activity/Practice

Time: 5 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher guides pupils to practice drawing different line types, parallel lines, and inclined lines on their drawing sheets, providing individual assistance where needed.
Pupils’ Activity: Pupils practice drawing the lines and constructions as demonstrated by the teacher.
Learning Point: Pupils apply their newly acquired skills under supervision.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

Define a thin continuous line and state its use.
Mention two uses of a thick continuous line.
What type of line is used for hidden details?
Describe how to draw parallel lines using a tee square and set squares.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 0 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key learning points about line types and their uses, and how to draw parallel and inclined lines. The teacher assigns homework: Pupils are to draw a simple object showing at least three different line types.
Pupils’ Activity: Pupils listen to the summary and copy down the assignment.
Learning Point: Pupils consolidate their understanding and are given an opportunity to practice further.

Lesson Keywords

Line Work – The act of drawing and using various types of lines in a technical drawing.
Continuous Line – A line drawn without breaks.
Chain Line – A line consisting of long and short dashes used for centre lines.
Hidden Line – A line made of short dashes, representing features that are not visible.
Parallel Lines – Lines that are equidistant apart and never intersect.
Inclined Lines – Lines drawn at an angle to the horizontal or vertical.
Tee Square – A T-shaped drawing instrument used for drawing horizontal lines and guiding set squares.
Set Squares – Triangular drawing instruments used for drawing lines at specific angles (e.g., 30°, 45°, 60°).

Differentiation

The teacher will provide additional support for pupils who are struggling by offering one-on-one guidance and simpler drawing exercises. Advanced pupils will be encouraged to draw more complex shapes incorporating various line types and constructions.

Note for teachers using this lesson plan

Ensure all drawing instruments are available and in good condition before the lesson. Emphasize the importance of neatness and accuracy in line work from the beginning. Encourage pupils to practice regularly to improve their drawing skills.