**Lesson Plan: Orthographic Projection of Buildings, Including Sectional Views and the Use of Different Scales (up to Floors Only)**
**Class:** Senior Secondary 2
**Subject:** Technical Drawing
**Duration:** 2 hours
**Lesson Objective:**
1. Define orthographic projection and explain its importance in technical drawing.
2. Illustrate and interpret orthographic projections of building floors.
3. Demonstrate creating sectional views of building components.
4. Apply different scales in drawing orthographic projections and sectional views.
**Materials Needed:**
- Drawing sheets
- Pencils (HB, 2H)
- Ruler
- Set squares
- Protractor
- Drawing compass
- T-Square
- Eraser
- Scale ruler
- Example blueprints or sample drawing
**Preparation:**
- Prepare examples of completed orthographic projections and sectional views.
- Draw simple building floor plans to practice projections and sections.
- Arrange drawing tools and materials for each student.
**Lesson Outline:**
**Introduction (15 minutes)**
1. **Greeting and Attendance (5 minutes)**
- Welcome students.
- Take attendance.
2. **Icebreaker and Pre-assessment (10 minutes)**
- Ask students if they have seen technical drawings of buildings before.
- Briefly discuss where orthographic projections are used (e.g., architecture, engineering).
**Body (60 minutes)**
1. **Explanation of Orthographic Projection (15 minutes)**
- Define orthographic projection: a method of representing three-dimensional objects on a two-dimensional plane.
- Discuss its importance in accurately conveying design intent and measurements.
- Show examples of orthographic projections.
2. **Drawing Orthographic Projections (20 minutes)**
- Describe the three primary views used in orthographic projections: plan (top view), front elevation (front view), and side elevation (side view).
- Illustrate step-by-step how to draw these views using a simple building floor plan.
- Emphasize correct alignment and scale usage.
3. **Introduction to Sectional Views (15 minutes)**
- Define sectional views and explain their purpose in showing interior details of buildings that cannot be seen in standard projections.
- Describe different types of sectional views (full, half, offset sections).
- Demonstrate how to draw a sectional view of a building floor, indicating cut planes and interior details.
4. **Using Different Scales (10 minutes)**
- Explain the importance of scales in technical drawing for accurate representation.
- Teach how to convert real-life dimensions into scaled drawings using a scale ruler.
- Provide examples of drawings in different scales (e.g., 1:50, 1:100).
**Activity (35 minutes)**
1. **Practical Exercise (30 minutes)**
- Distribute the prepared example building floor plan to each student.
- Guide students step-by-step to draw orthographic projections and a sectional view of the plan.
- Ensure students apply the appropriate scale to their drawings.
2. **Review and Feedback (5 minutes)**
- Circulate around the room, providing individual feedback and assistance.
- Discuss common mistakes and corrective measures.
**Conclusion (10 minutes)**
1. **Q&A Session (5 minutes)**
- Invite students to ask questions about the lesson.
- Address any confusion and provide clarifications.
2. **Summary and Assignment (5 minutes)**
- Summarize the lesson's key points.
- Assign homework: Ask students to choose a simple building (e.g., their home or school) and create orthographic projections and a sectional view.
- Remind students to apply proper scales in their homework.
**Assessment:**
- Evaluate the students' in-class activities for accuracy, alignment, and correct scale application.
- Review the assigned homework for comprehension and skill application.
**Resources:**
- Reference textbooks on Technical Drawing fundamentals.
- Online tutorials and videos on orthographic projections and sectional views.
- Software tools (optional) like AutoCAD for advanced students.
This lesson plan provides a comprehensive structure to teach Senior Secondary 2 students about orthographic projections of buildings, including sectional views and the appropriate use of scales.