TERM – 2^{ND} TERM
WEEK FIVE
Class: Senior Secondary School 1
Age: 15 years
Duration: 40 minutes of 5 periods each
Date:
Subject: Technical Drawing
Topic: DIAGONAL AND CHORDAL SCALES
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
I.) Define a diagonal scale
II.) Differentiate between a diagonal scale and a chordal scale.
III.) Construct a diagonal scale and a chordal scale
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 Differentiate a diagonal scale from a chordal scale |
Students listens attentively to the teacher |
STEP 2 EXPLANATION |
Teacher guide students to construct diagonal scale and chordal scale. |
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
DIAGONAL AND CHORDAL SCALES
Diagonal scale
A diagonal scale is a type of scale used in technical drawings, maps, and blueprints to represent distances accurately at different scales. Diagonal scale is used to read lengths with higher accuracy as it represents a unit into three different multiple in metres, centimeters and millimeters. It consists of a series of diagonal lines or bars, each representing a specific unit of measurement.
To construct a diagonal scale:
Chordal scale
A chordal scale, also known as a string scale, is a type of scale used in engineering and technical drawings to represent distances accurately at different scales. It consists of a series of arcs or circles with their radii corresponding to different units of measurement.
To construct a chordal scale:
EVALUATION: 1. Differentiate between diagonal scale and chordal scale
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively