# Lesson Notes By Weeks and Term - Senior Secondary 1

Isometric drawing 1

TERM – 3RD TERM

WEEK SEVEN

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Technical Drawing

Topic: ISOMETRIC DRAWING 1

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Define isometric projection

II.) Discuss the isometric axis and angles

III.) Describe the principle of parallel lines.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher introduces isometric projection and discuss the angles and axes. Students listens attentively to the teacher STEP 2 EXPLANATION Teacher discusses the principles of parallel lines. Students exhibit attentiveness and active engagement STEP 3 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

ISOMETRIC DRAWING 1

Isometric drawing is a type of pictorial drawing used in technical and engineering illustrations to represent three-dimensional objects in two dimensions. In an isometric drawing, the object is presented with its three principal dimensions (length, width, and height) parallel to the three isometric axes at 120-degree angles to each other. This results in a representation where all three dimensions of the object are equally foreshortened, giving the drawing a more realistic appearance compared to orthographic projections.

Isometric axes and angle

The angle that is use to present any object in isometric form is 30⁰. However, this angle is placed within some lines called isometric axis. The 30⁰ is placed between two slant lines and a horizontal line. In the diagram below, X, Y and Z are the axes of the projection, while Alpha and Beta(indicated by symbols) are the angles in the projection.

Principle of parallel lines

This is the principle that actually does the drawing. The technician simply follows the stated rule in this principle. Whether the person knows how to draw anything or not, by carefully following the rule, he or she will be able to draw any shape in isometric forms. The rule states that:

"All vertical, horizontal, slant (inclined) and curved lines must remain parallel unless the shape of the object suggests otherwise."

EVALUATION: 1. What is isometric projection ?

1. Draw a cabinet in isometric projection

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively