# Lesson Plan: Orthographic Projection in Technical Drawing
## Grade Level: Senior Secondary 2
### Grade: Senior Secondary 2
### Subject: Technical Drawing
### Duration: 70 minutes
### Topic: Orthographic Projection
### Objective:
By the end of the lesson, students will be able to:
1. Understand the concept of orthographic projection.
2. Identify the three main views used in orthographic projections (front, top, and side).
3. Draw simple orthographic projections of basic 3D objects.
4. Apply proper scaling and dimensioning techniques in their drawings.
### Materials Needed:
- Whiteboard and markers
- Projector and computer
- Ruler, compasses, protractors
- Graph paper
- 3D models for demonstration (e.g., cubes, cylinders, cones)
- Technical drawing textbooks or reference materials
### Lesson Outline:
#### **Introduction (10 minutes)**
1. **Greeting and Motivation:**
- Start with a question, "Have you ever seen blueprints or engineering sketches of machines or buildings? How do you think those are created?"
- Discuss the importance of technical drawing in engineering, architecture, and manufacturing.
- Introduce the topic: Orthographic Projection.
2. **Learning Objectives:**
- Clearly state the objectives of the lesson and what students will achieve by the end.
#### **Lesson Body (45 minutes)**
1. **Definition and Purpose (10 minutes):**
- Explain what orthographic projection is: A method of representing three-dimensional objects in two dimensions.
- Emphasize the purpose: To accurately convey the dimensions and geometry of an object through multiple 2D views.
2. **Understanding the Three Views (15 minutes):**
- **Front View:** The view from the front of the object.
- **Top View:** The view from above the object.
- **Side View:** The view from the side of the object.
- Use a projector to show examples of each view from an object.
- Demonstrate with a physical 3D model, rotating it to show each view.
3. **Drawing Simple Orthographic Projections (20 minutes):**
- Use basic geometric shapes (e.g., cubes, cylinders) to show how to draw each view.
- Step-by-step drawing instructions on the whiteboard.
- Discuss scaling and dimensioning conventions in technical drawing.
4. **Class Activity:**
- Distribute worksheets with 3D objects depicted.
- Students should draw the orthographic projections based on the given 3D objects.
- Monitor and assist students as needed.
#### **Conclusion (15 minutes)**
1. **Review and Recap:**
- Ask questions to review key points (e.g., "What are the three main views in orthographic projection?").
- Quickly go over the steps involved in creating an orthographic projection.
2. **Q&A Session:**
- Open the floor for any questions or doubts.
3. **Assignment:**
- Assign a homework task where students must choose a household item and draw its orthographic projection (front, top, and side views).
4. **Closing Remarks:**
- Summarize the importance of precision and practice in mastering technical drawing skills.
- Encourage students to review their notes and practice drawing different objects.
### Assessment:
- Monitor students during the class activity and provide immediate feedback.
- Review and grade the homework assignment for understanding and accuracy.
- Conduct a short quiz in the following class to assess comprehension of orthographic projection principles.
### References:
- “Technical Drawing with Engineering Graphics” by Frederick E. Giesecke, Alva Mitchell, Henry C. Spencer, and John T. Dygdon.
- Online tutorials and videos on orthographic projection.
- Technical drawing software (for advanced practice)
### Additional Notes:
- Adapt the complexity of the objects based on students' progress and understanding.
- Incorporate digital tools (like CAD software) in future lessons to enrich the learning experience.
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This lesson plan balances theory and practical application, ensuring that students grasp the fundamental concepts and the value of orthographic projection in technical drawing.