Lesson Plan Teknis | Surface Expansion

Objective

Duration: (10 - 15 minutes)

The aim of this stage of the lesson plan is to ensure that learners grasp the fundamental concepts of thermal expansion, linking them to practical scenarios and the job market. Developing practical skills is vital for learners to apply theoretical knowledge in real-world contexts such as engineering and industry, where thermal expansion can impact the structural integrity of materials and components.

Objective Utama:

1. Understand the basic concepts of thermal expansion and how this applies to various materials.

2. Solve real-world problems involving the thermal expansion of solid objects.

3. Use the knowledge gained to tackle specific scenarios, such as the expansion of holes in metal sheets.

Objective Sampingan:

Introduction

Duration: (15 - 20 minutes)

The aim of this segment is to contextualise the topic of thermal expansion, connecting it to real-life situations and the job market while piquing learners' interest and curiosity through an engaging introduction.

Curiosities and Market Connection

Did you know that bridges and overpasses incorporate expansion joints to prevent structural damage from temperature changes? Additionally, in the aerospace sector, it’s critical to consider the thermal expansion of materials to prevent serious failures in aircraft. In electronics manufacturing, like for smartphones and computers, managing material expansion is necessary to avoid malfunctions.

Contextualization

Thermal expansion is a physical process that happens when solid materials expand or contract due to changes in temperature. This principle is not only important in physics but also in a variety of practical applications that we encounter daily, such as in construction, manufacturing mechanical components, and materials engineering. Understanding how materials respond to different temperatures is critical for guaranteeing the safety and longevity of structures and devices.

Initial Activity

Encourage learners to watch a short 3-minute video demonstrating thermal expansion in various materials. After viewing, pose the following thought-provoking question: How do you think thermal expansion can impact the safety of a building during different seasons?

Development

Duration: (60 - 65 minutes)

The objective of this stage is to guarantee that learners comprehend and apply the principles of thermal expansion in real-life situations and within the job market. By engaging in model-building and problem-solving, learners cultivate practical and reflective skills vital for their academic and professional growth.

Topics

1. Concept of thermal expansion

2. Coefficient of thermal expansion

3. Practical applications of thermal expansion

4. Problems involving holes in metal sheets

5. Impact of thermal expansion on various materials and structures

Thoughts on the Subject

Guide learners to reflect on how thermal expansion can influence everyday structures, like bridges, buildings, and vehicles. Pose questions about how engineers and architects manage these challenges and what measures are necessary to ensure the safety and longevity of constructions and devices.

Mini Challenge

Mini Challenge: Building a Bridge with Expansion Joints

Learners will construct a model of a bridge using simple materials such as ice lolly sticks, hot glue, and rubber bands. The model should include expansion joints that accommodate the structure's expansion and contraction due to temperature fluctuations.

1. Divide learners into groups of 4 to 5 members.

2. Provide the required materials: ice lolly sticks, hot glue, rubber bands, and a cardboard base.

3. Instruct groups to design and build a small bridge, incorporating rubber bands as expansion joints.

4. After building, ask each group to explain how their expansion joints function and why they matter.

5. Facilitate a discussion around the challenges faced and the solutions implemented by each group.

To develop practical construction and design skills while understanding the significance of expansion joints in structures subjected to temperature fluctuations.

**Duration: (40 - 45 minutes)

Evaluation Exercises

1. Calculate the area change of a 2m² aluminium sheet when the temperature rises from 25°C to 75°C. The coefficient of superficial expansion for aluminium is 48 x 10^-6 °C^-1.

2. A steel sheet has a circular hole with an initial radius of 5 cm. If the temperature of the sheet increases by 50°C, and knowing that the coefficient of superficial expansion for steel is 24 x 10^-6 °C^-1, what is the new radius of the hole?

3. Discuss how thermal expansion might affect the safety of train tracks on a very hot day.

Conclusion

Duration: (10 - 15 minutes)

This phase of the lesson plan aims to reinforce learning, ensuring that learners appreciate the practical significance of the concepts studied. By promoting discussion and reflection, learners have the opportunity to internalize knowledge, linking theory to practice and understanding its relevance in the job market and their daily lives.

Discussion

Encourage learners to discuss what they have learnt throughout the lesson, particularly regarding the practical applications of thermal expansion. Ask them about the challenges faced during the bridge construction mini challenge and how they overcame these issues. Facilitate a reflection on how theoretical principles were applied in practice and the usefulness of this knowledge in their future careers, whether in engineering, architecture, or related fields.

Summary

Summarize the key points discussed, stressing the concept of thermal expansion, the coefficient of thermal expansion, and the practical uses of these concepts. Highlight the problems tackled involving holes in metal sheets and the importance of expansion joints in structures experiencing temperature changes.

Closing

Clarify to learners how the lesson linked theory with practice and its implications in the job market. Highlight the necessity of grasping thermal expansion to ensure the safety and durability of various structures and devices in everyday life. Conclude by emphasizing that the knowledge acquired is vital not only for physics but also across numerous professional fields, and that the capability to apply theoretical concepts in practical contexts is a significant asset in the job market.