Contextualization

The first law of thermodynamics, also known as the law of conservation of energy, is a central concept in physics. It states that energy cannot be created or destroyed, only converted from one form to another. Thus, the total energy of an isolated system remains constant.

This law has deep and varied applications, from internal combustion engines that power our cars to power plants that provide electricity to our homes. More significantly, the first law of thermodynamics gives us a complete and cohesive understanding of how work, internal energy, and heat exchanged between systems can be calculated and predicted.

Studying the first law of thermodynamics provides us with valuable insight into natural processes and a solid foundation for technological innovations. For example, the efficiency of engines, the optimization of industrial processes, and the development of new renewable energy sources are all direct applications of this law.

Therefore, the importance of this topic should not be underestimated. By mastering the first law of thermodynamics, you, as students, will be acquiring skills that can be applied in various careers, including engineering, materials science, chemistry, and even economics.

To deepen the understanding of the topic, I recommend the following resources:

• Book: "Physics for Scientists and Engineers - Volume 1", by Paul A. Tipler and Gene Mosca.
• Videos: YouTube channel Ciência todo dia has a series of videos on thermodynamics.
• Website: Brasil Escola offers a clear and accessible explanation of the first law of thermodynamics.

Practical Activity

Activity Title: "Building a Homemade Stirling Engine"

Project Objective:

Demonstrate the application of the first law of thermodynamics through the construction of a simple and functional model of a Stirling engine, a type of heat engine.

Detailed Project Description: Students will be divided into groups of three to five members and will build a prototype of a Stirling Engine, document the entire creation and testing process, and create a report addressing the project, its results, and how the first law of thermodynamics applies at each stage.

Materials Needed:

1. 2 empty soda cans;
2. Party balloon;
3. 4 bottle cork stoppers;
4. Copper wire;
5. Candle;
6. Cotton and alcohol;
7. Scissors and glue.

Detailed Step-by-Step for the Activity:

1. One group member should research the basic operation of the Stirling Engine and explain it to the others;
2. After the theoretical explanation, everyone should participate in building the Engine. Use the 2 soda cans to form the hot and cold chambers of the engine;
3. The balloon will be used as the piston that will be moved by heat;
4. The cork stoppers will seal the chambers, and the copper wire will be the piston shaft;
5. Use the candle to generate the heat necessary for the engine to function. For safety, cotton soaked in alcohol can be used as a more controlled alternative to fire;
6. Document the entire process through photos, videos, and notes, as this will be necessary for the report.

Project Deliverables and How They Connect to the Project:

1. Final Report: The report should be written in the format of a scientific article, divided into four main parts: Introduction, Development, Conclusions, and Bibliography.

   • (Introduction): Students should explain the purpose of building the Stirling engine, contextualizing the application of the first law of thermodynamics.

   • (Development): Here, students should detail the entire construction and testing process of the engine, with attachments of photos, videos, and diagrams illustrating the process. Theoretical explanations of the engine's operation and how the first law of thermodynamics applies at each stage of the engine's operation should also be presented.

   • (Conclusions): Students should summarize the main results obtained, what they learned during the process, and what difficulties they encountered.

   • (Bibliography): They should reference all the consultation materials used during the project.

2. Oral Presentation: Each group must present their project to the class, highlighting the main points of the project and demonstrating the operation of the built engine.

Project Duration: One month. During this time, students should organize themselves to divide tasks and meet the established deadlines.

Group Size: 3 to 5 students.

At the end of the project, students should be able to apply the concepts of the first law of thermodynamics to explain the operation of the Stirling engine, as well as develop skills such as teamwork, problem-solving, time management, and creative thinking.