Contextualization

The world of photography has countless techniques and equipment to explore, but before all these modern resources, there was something simple and powerful: the Camera Obscura. This device is one of the oldest concepts in the history of photography and the study of light, dating back thousands of years.

The camera obscura is a closed box that has a small hole on one of its sides, which allows light to pass through. The light that enters through this hole projects an inverted image of the outside on the opposite side of the box. From this simple principle, it is possible to explore fundamental concepts in the study of physics, such as the rectilinear propagation of light, reflection, and refraction.

Importance and Real-World Applications

The principle of the camera obscura is the foundation of modern photography and cinematography. In fact, photographic cameras are essentially improved camera obscuras with lenses and a film or sensor to capture the projected image.

Furthermore, the camera obscura also has various applications in sciences such as astronomy, where it has been used to observe solar eclipses safely. Even in art, artists like Leonardo Da Vinci and Vermeer used it as an aid to create drawings and paintings with precise perspective.

Knowing its relevance, why not build a Camera Obscura ourselves? Let's put into practice the studied physics concepts and still have a glimpse of the history of photography and optical sciences.

Practical Activity: Building and Experimenting with the Camera Obscura

Project Objective:

Students will design, build, and conduct experiments with a camera obscura in order to understand the concepts of light reflection and refraction. Throughout this project, students will also enhance their teamwork skills, critical thinking, problem-solving, and communication.

Detailed Project Description:

Student groups will be tasked with building a camera obscura using common materials, testing it, and conducting experiments to understand how it works and how light behaves. They will be challenged to adjust the camera to achieve the best possible image and to investigate how varying certain parameters (such as the size of the hole or the distance from the object to the hole) affects the image. They will then use these results to formulate a comprehensive report on their findings.

Required Materials:

• A shoebox or any box of similar size
• Aluminum foil
• Tape
• Scissors
• White paper

Step by Step:

1. Take the shoebox and cut a small square (about 2cm x 2cm) on one of the ends.

2. Cover the hole with aluminum foil and secure it with tape.

3. Make a very small hole (about 1mm in diameter) in the aluminum foil, using a pin or needle.

4. Inside the box, at the end opposite the hole, place a sheet of white paper. This will be the screen where the image will be projected.

5. Close the box so that no light enters, except through the hole made in the aluminum foil.

6. Point the hole of the camera obscura towards a well-lit object. You can start with a window during the day. The image of the object (inverted) will be projected on the paper inside the box.

7. Now experiment: change the aluminum foil (and consequently the hole) for others of different sizes, change the distance between the box and the object, try with different illuminations, and observe the changes in the projected image.

8. Document all steps, observations, and changes made during the experiments.

Project Deliverables:

At the end of the project, each group must submit a written report containing the following parts:

1. Introduction: In this section, the group must explain the theory of the camera obscura and the project's objective.

2. Development: Here the group must describe in detail the entire process of building and experimenting with the camera obscura. Students should explain the experiments they conducted, the variables they changed, and what they observed with each change. They should also explain the methodology used to conduct the experiments.

3. Conclusions: Students must conclude the work by summarizing their main points, explaining the learnings obtained, and the conclusions drawn about the project.

4. Bibliography: The group must indicate the sources of information used to understand the theory and develop the project.

The report should be written clearly, covering all the details of the camera obscura's construction and the experiment, as well as the interpretation of the results obtained. The report will be the opportunity to express the theoretical and practical understanding of how the camera obscura works. Additionally, students will have to make a presentation to the class, explaining the process and discussing their results.