TERM – 3^{RD} TERM
WEEK TEN
Class: Junior Secondary School 3
Age: 14 years
Duration: 40 minutes of 5 periods each
Date:
Subject: BASIC TECHNOLOGY
Topic: ORTHOGRAPHIC PROJECTION
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,
demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures, mathematical sets, drawing instruments
INSTRUCTIONAL PROCEDURES
PERIOD 1-2
PRESENTATION |
TEACHER’S ACTIVITY |
STUDENT’S ACTIVITY |
STEP 1 INTRODUCTION |
The teacher explains the meaning of orthographic projection to the students |
Students pay attention |
STEP 2 EXPLANATION |
Teacher discuss the types of orthographic projection |
Students pay attention and participate |
STEP 3 DEMONSTRATION |
Teacher explains dimensions techniques and guide students to construct simple objects |
Students pay attention and participate |
STEP 4 NOTE TAKING |
The teacher writes a summarized note on the board |
The students copy the note in their books |
NOTE
ORTHOGRAPHIC PROJECTION
An orthographic drawing, also known as an orthographic projection, is a drawing in which a three-dimensional object is represented in two dimensions. This is is done making multiple two-dimensional drawings of the object, viewed from different angles.
Types of orthographic Projection
The methods used in orthographic projection, a technique for representing a three-dimensional object in two dimensions are:
1. First Angle Projection: In this method, the object is imagined to be located in the first quadrant (positive quadrant) of the imaginary coordinate system. The object is positioned between the observer and the plane of projection, with the principal planes (front, top, and side views) arranged accordingly.
2. Third Angle Projection: In contrast, third angle projection assumes the object is in the third quadrant (negative quadrant) of the imaginary coordinate system. The object is placed behind the plane of projection, and its views are projected onto the planes with the principal views arranged similarly to how they would be seen by the observer.
Drawing of Orthographic Views of Simple Objects
Procedure
The following steps take you through the creation of an orthographic projection.
Dimension Techniques
The three principal dimensions of an object are width, height, and depth. The front view shows only the height and width of the object and not the depth. In fact, any principal view of a 3D object shows only two of the three principal dimensions; the third is found in an adjacent view.
EVALUATION: 1. What is orthographic projection
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively