Lesson Plan Teknis | Surface Expansion

Objective

Duration: (10 - 15 minutes)

This stage of the lesson plan aims to ensure that students understand the core concepts of thermal expansion by relating them to real-life scenarios and job market needs. Building practical skills is essential for students to leverage their theoretical knowledge in hands-on situations, like in engineering or industry, where thermal expansion can impact the structural integrity of materials and components.

Objective Utama:

1. Grasp the fundamental concepts of thermal expansion and how they apply to various materials.

2. Tackle practical problems related to the thermal expansion of solid objects.

3. Utilize the knowledge gained to address specific issues, such as the expansion of holes in sheets.

Objective Sampingan:

Introduction

Duration: (15 - 20 minutes)

The aim of this stage is to set the context for thermal expansion, linking it to real-world situations and job prospects, while engaging students' interest through an interactive introductory activity.

Curiosities and Market Connection

Did you know that bridges and overpasses are equipped with expansion joints to prevent structural damage from temperature fluctuations? In the aerospace sector, considering thermal expansion of materials is crucial to avoid severe failures in aircraft. Furthermore, in manufacturing electronics like smartphones and computers, managing material expansion is necessary to prevent malfunctions.

Contextualization

Thermal expansion is a physical phenomenon where solid materials expand or contract due to changes in temperature. This concept is not only vital in physics but also found in various everyday applications, such as construction, manufacturing of mechanical parts, and materials engineering. Understanding how materials react to temperature fluctuations is key to ensuring the safety and longevity of structures and devices.

Initial Activity

Have students watch a short 3-minute video that showcases thermal expansion in various materials. After the video, pose this thought-provoking question: How might thermal expansion impact the safety of a building across different seasons?

Development

Duration: (60 - 65 minutes)

This stage of the lesson plan is designed to ensure students comprehend and apply the concepts of thermal expansion in practical contexts relevant to the job market. By building models and solving problems, students develop the practical and reflective skills essential for their academic and professional pursuits.

Topics

1. Thermal expansion concept

2. Coefficient of thermal expansion

3. Real-world applications of thermal expansion

4. Challenges with holes in metal sheets

5. Effects of thermal expansion on various materials and structures

Thoughts on the Subject

Encourage students to consider how thermal expansion impacts everyday structures, including bridges, buildings, and vehicles. Ask them how they feel engineers and architects tackle these challenges, and what measures are needed to ensure the safety and durability of buildings and devices.

Mini Challenge

Mini Challenge: Building a Bridge with Expansion Joints

Students will construct a model bridge using simple materials like popsicle sticks, hot glue, and rubber bands. The model must include expansion joints to allow for the movement due to temperature changes.

1. Divide students into groups of 4 to 5.

2. Provide the necessary materials: popsicle sticks, hot glue, rubber bands, and a cardboard base.

3. Instruct the groups to design and build a small bridge, integrating rubber band expansion joints.

4. Once built, have groups demonstrate how their expansion joints function and explain why they are essential.

5. Lead a discussion on the challenges faced and the innovative solutions the groups developed.

Enhance practical construction and design skills, while illustrating the importance of expansion joints in temperature-sensitive structures.

**Duration: (40 - 45 minutes)

Evaluation Exercises

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

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

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

Conclusion

Duration: (10 - 15 minutes)

This stage of the lesson plan aims to consolidate learning, ensuring that students recognize the practical importance of the concepts studied. By promoting discussion and reflection on the topic, students get the chance to internalize knowledge, connecting theory to practice and appreciating its relevance in the job market and everyday life.

Discussion

Facilitate a discussion where students share what they learned during the lesson, focusing on practical applications of thermal expansion. Encourage them to talk about the challenges they faced during the bridge-building mini challenge and how they resolved those issues. Lead a reflection on how theoretical concepts were practically applied and how this knowledge will benefit their future careers, whether in engineering, architecture, or related fields.

Summary

Summarize the key content covered, emphasizing the concept of thermal expansion, its coefficient, and the real-world applications of these ideas. Highlight the problems solved regarding holes in metal sheets and the significance of expansion joints in temperature-sensitive structures.

Closing

Conclude by explaining how the lesson bridged theory to practical applications relevant in the job market. Stress the importance of understanding thermal expansion to maintain the safety and durability of structures and devices in daily life. Reinforce that this knowledge is vital not only for physics but also across various professional paths, and that the ability to apply theory in practical scenarios is a valuable skill in today’s job landscape.