Contextualization

Physics, a discipline loved by many and feared by some, has as one of its branches the study of geometric optics. In this segment of physics, different concepts and luminous phenomena are addressed, among them, the flat mirror stands out. This is one of the most common mirrors we encounter in our daily lives, from bathroom mirrors to the rearview mirrors of the vehicles we use in our daily movements. Mastering the theory behind this phenomenon allows us to understand various visual phenomena that we experience routinely, but that often go unnoticed.

A flat mirror is one whose reflecting surface is flat and smooth. The surface can be made of glass, metal, or any other polished material that reflects light. The image formed by a flat mirror has the following characteristics: it is virtual (cannot be projected), upright (not inverted), and the same size as the object. In addition, the distance from the image to the mirror is equal to the distance from the object to the mirror.

Analyzing the different representations of the real world that we see in flat mirrors, we realize that it is not a simple 1:1 representation of reality. In fact, we perceive an inverted world, both laterally and in depth. Through the study of flat mirrors, we can deepen our understanding of how light and images interact, allowing for the production of rearview mirrors and high-definition cameras.

In the practical world, the study of mirrors is of great relevance. Mirrors are widely used in various sectors of industry and science. In medicine, for example, mirrors are used in diagnostic instruments. In construction, they are used to improve lighting and visibility. In astronomy, large mirrors are an essential part of the telescopes we use to observe the universe. The lessons we learn from flat mirrors form the basis for understanding curved mirrors, which have even more practical applications.

To deepen knowledge, I suggest the following sources for research and study:

1. EDUCATION PORTAL. Flat mirrors: characteristics and properties. Available at: https://www.portaleducacao.com.br/conteudo/artigos/ensino-medio/espelhos-planos-caracteristicas-e-propriedades/58789. Accessed on: Oct 20, 2021.
2. SOUZA, C. A. Geometric Optics: Light reflection. São Paulo: FTd, 2018.
3. JUST PHYSICS. Flat Mirrors. Available at: https://www.sofisica.com.br/conteudos/Mecanica/Otica/espelhosplanos.php. Accessed on: Oct 20, 2021.
4. YOUTUBE. The physics of Mirrors | Nerdologia. Available at: https://www.youtube.com/watch?v=vbFvJo1G2Yc. Accessed on: Oct 20, 2021.

Practical Activity: "The Magic of Flat Mirrors"

Project Objectives

Students should:

• Understand and experimentally verify the properties of images formed by flat mirrors.
• Design a "mirror maze" that demonstrates light reflection.
• Apply theoretical concepts of geometric optics and flat mirrors in the project construction.
• Describe the entire process and the results obtained in an academic report.

Detailed Project Description

In this project, student groups will explore the properties of flat mirrors by constructing a "mirror maze." The maze will be built using small mirrors, so that light can be reflected several times before exiting the maze. From this, students will observe how light reflects and can experimentally confirm the properties of light reflection in flat mirrors.

Required Materials

• Small mirrors (from 5 to 10, depending on the maze size)
• Cardboard or paperboard for the maze base
• Glue
• Paper straw or laser pointer
• Adhesive tape
• Ruler and square

Detailed Step-by-Step

1. Research the characteristics and properties of flat mirrors, using the suggested sources or others you find.
2. Plan the mirror maze: try to create a path in which light will reflect at least 3 times before exiting the maze. Make sure the path follows the rules of light reflection in flat mirrors.
3. Mark the maze planning on the cardboard or paperboard, including the locations where the mirrors will be placed.
4. Glue the mirrors in the marked locations. Use the ruler and square to ensure the mirrors are in the correct position.
5. Test the maze by placing a paper straw or laser pointer at the maze entrance and observe the path of light.
6. Make adjustments to the maze, if necessary, until the reflected light follows the planned path.
7. Document the entire construction and testing process of the maze, including failures and successes, so that you can describe in detail in the report.

Project Deliverables

At the end of the project, each student group should present:

• The constructed mirror maze.
• An academic report, containing:
  • Introduction: Describing the context of flat mirrors and the relevance of this study.
  • Development: Detailing the theory behind flat mirrors, the methodology used for planning and constructing the mirror maze, the results obtained, and the discussion about these results.
  • Conclusion: Summarizing the main points of the work, reflecting on what they learned, and establishing connections between theory and practice.
  • Bibliography: Citing all sources of information consulted for the project.

The report should be written in a clear and objective manner, demonstrating the knowledge acquired during the project. It is important for students to discuss not only the results but also the difficulties encountered and how they were overcome, as well as the skills developed during the work, especially regarding collaboration and teamwork.