# Lesson Plan for Technical Drawing: Enlargement and Reduction of Plain Figures
### Grade Level: Senior Secondary 1
### Subject: Technical Drawing
### Duration: 90 minutes
### Topic: Enlargement and Reduction of Plain Figures
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### Learning Objectives:
1. **Understand the concepts** of enlargement and reduction in technical drawing.
2. **Apply scale factors** to enlarge or reduce plain figures accurately.
3. **Develop skills** in using technical drawing tools effectively.
4. **Appreciate the practical applications** of enlargement and reduction in engineering and design.
### Materials Required:
- Drawing paper
- Technical drawing pencils (2H, H, HB)
- Rulers
- Compasses
- Protractors
- Set squares
- Erasers
- Scale rulers
- Graph paper
- Example plain figures (handouts)
### Key Vocabulary:
- Scale Factor
- Enlargement
- Reduction
- Plain Figures
- Proportions
### Activities and Time Breakdown:
#### Introduction (10 minutes)
1. **Welcome and Warm-Up:**
- Greet the students and introduce the day’s topic.
2. **Review of Previous Lesson:**
- Briefly discuss key points from the previous lesson on basic geometric drawing.
3. **Introduction to New Topic:**
- Explain the concepts of enlargement and reduction.
- Discuss real-life applications (e.g., architecture, engineering, and design).
#### Direct Instruction (20 minutes)
1. **Demonstration:**
- Use a plain figure (e.g., a square or triangle) and demonstrate how to enlarge and reduce it using a scale factor.
- Show how to use the technical drawing tools for accuracy.
2. **Explain Scale Factors:**
- Define scale factor and show mathematical calculations for enlarging and reducing figures (e.g., Multiplying by 2 for enlargement, 1/2 for reduction).
3. **Step-by-Step Guide:**
- Provide a step-by-step process for applying scale factors to plain figures.
#### Guided Practice (30 minutes)
1. **Enlargement Activity:**
- Provide students with a simple plain figure and ask them to enlarge it by a scale factor of 2.
- Circulate the classroom, provide support and feedback.
2. **Reduction Activity:**
- Provide students with another plain figure and ask them to reduce it by a scale factor of 1/2.
- Continue to offer guidance and check for understanding.
#### Independent Practice (20 minutes)
1. **Individual Tasks:**
- Assign each student a different plain figure on graph paper and ask them to choose a scale factor for enlargement and another for reduction.
- Encourage students to apply the process independently.
#### Review and Closing (10 minutes)
1. **Peer Review:**
- Have students pair up and review each other’s drawings, providing constructive feedback.
2. **Q&A Session:**
- Address any questions or concerns from students regarding the lesson.
3. **Homework Assignment:**
- Assign a take-home task where students will draw a plain figure and enlarge and reduce it with different scale factors.
4. **Summary and Wrap-Up:**
- Summarize the key points of the lesson.
- Preview the next lesson topic.
### Assessment:
- **Formative Assessment:** Monitor students’ progress during guided practice and provide immediate feedback.
- **Summative Assessment:** Evaluate the accuracy of students' independent practice drawings and the take-home assignment.
### Differentiation:
- **For Advanced Students:** Challenge them with more complex plain figures and different scale factors.
- **For Struggling Students:** Provide additional one-on-one support and simpler figures initially.
### Reflection:
- **Teacher’s Reflection:**
- Reflect on the effectiveness of the lesson.
- Note what went well and areas for improvement.
- Consider student engagement and understanding for future planning.
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### Standards Alignment:
- **STEM/Technical Education Standards:** Ensure alignment with relevant curriculum standards for technical drawing and engineering.
### Notes:
- Ensure all students have access to the necessary drawing tools.
- Encourage a positive and supportive learning environment conducive to technical skill development.
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This lesson plan aims to build foundational skills in technical drawing focused on enlargement and reduction, fostering both practical proficiencies and theoretical understanding for Senior Secondary 1 students.