# Lesson Notes By Weeks and Term - Senior Secondary 1

Plain scales

TERM – 2ND TERM

WEEK FOUR

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Technical Drawing

Topic: PLAIN SCALES

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

I.) Define plain scale

II.) Discuss the uses of plane 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 explains the meaning of plane scale to the students Students listens attentively to the teacher STEP 2 EXPLANATION Teacher discusses the uses of plane scale using the scale tool. 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

PLAIN SCALES

A plain scale, also known as a linear scale, is a measuring tool used in technical drawing, engineering, architecture, and other fields. It consists of a straight line divided into evenly spaced increments, each representing a specific unit of measurement, such as inches, centimeters, or millimeters.

The term scale also refer to the ratio of the size of a drawing to the size of the actual object. The ratio or fraction is called the representative fraction of the scale.

The Representative fraction (R.F) = distance or size represented.

The following are the common used RF:

1:1 Full size image

1:2 Half full size

1:5 One - fifth full size

1:10 One - tenth full size

5:1 Five times the full size

Uses of plain scales

The primary uses of plain scales include:

1. Engineers, architects, and designers use plain scales to measure distances on blueprints, technical drawings, and maps accurately.
2. Plain scales enable the conversion of distances on paper to real-world distances. By using the scale provided on a drawing, one can determine the actual dimensions of objects being represented.
3. Artists and drafters use plain scales to draw accurate lines and shapes to scale. By referencing the scale, they ensure that their drawings are proportional and correctly sized.
4. Plain scales can also be used for rough estimation. By quickly measuring distances on a map or drawing, one can estimate lengths without the need for precise measurements.

EVALUATION: 1. What is a plane scale

1. Briefly describe the uses of plane scale

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively