Objectives (5 - 7 minutes)

1. Understand the concept of Biogeochemical Cycle: Students should be able to define what a biogeochemical cycle is and identify the main components of each one (chemical elements, processes, and compartments).

2. Analyze the Nitrogen, Carbon, and Water Cycles: Students should be able to describe in detail the nitrogen, carbon, and water cycles, identifying the main processes that occur in each one, as well as the locations where these cycles are most intense.

3. Relate Biogeochemical Cycles to Environmental Sustainability: Students should be able to understand the importance of biogeochemical cycles for environmental sustainability, identifying how human intervention can affect these cycles and, consequently, the balance of ecosystems.

Secondary Objectives:

• Develop Critical Thinking: Students will be encouraged to think critically about the impact of human actions on biogeochemical cycles and the importance of preserving these cycles for the maintenance of life on Earth.

• Promote Group Discussion: Students will be divided into small groups to carry out practical activities, promoting discussion and the exchange of ideas among them.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should start the lesson with a quick review of the concepts of ecology, biomes, and ecosystems, highlighting the interdependence between living beings and the environment. For example, he can question students about how living beings obtain energy and nutrients, and how these processes are linked to biogeochemical cycles. (3 - 5 minutes)

2. Presentation of Problem Situations: The teacher can then present two problem situations to arouse students' interest and contextualize the lesson theme. For example, he can ask:

   • "How does the burning of fossil fuels affect the carbon cycle and contribute to global warming?"
   • "How can the intensive use of nitrogen fertilizers in agriculture lead to river and sea pollution and the emergence of 'dead zones'?"

   These questions should serve as a starting point for the exploration of biogeochemical cycles and their relationship with environmental sustainability. (3 - 5 minutes)

3. Contextualization of the Subject's Importance: Next, the teacher should contextualize the importance of studying biogeochemical cycles, highlighting how these processes are fundamental for the maintenance of life on Earth. For example, he can mention that without the water cycle, there would be no rain, rivers, seas, and consequently, life. Similarly, without the carbon cycle, there would be no photosynthesis and therefore no oxygen production. The teacher can also briefly discuss the consequences of the imbalance of these cycles, such as global warming and pollution of aquatic ecosystems. (3 - 5 minutes)

4. Capturing Students' Attention: To capture students' attention, the teacher can share some curiosities about biogeochemical cycles. For example:

   • "Did you know that the carbon in your body right now may have been in the atmosphere, soil, and sea? This happens thanks to the carbon cycle!"
   • "Did you know that the water you drank today may have been drunk by a dinosaur millions of years ago? This is possible thanks to the water cycle!"

   These curiosities should help arouse students' curiosity and demonstrate the practical importance of biogeochemical cycles. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Puppet Theater Activity (10 - 12 minutes): The teacher should divide the class into small groups and provide each group with a set of puppets representing the main elements of nature (for example, a carbon atom puppet, a water molecule puppet, a nitrogen-fixing bacteria puppet, etc.). Each group will receive a short play to perform, where the characters (the puppets) interact with each other, representing the different processes of biogeochemical cycles. The plays should be short (approximately 5 minutes) and creative, encouraging students to use their imagination and sense of humor. For example, in a play about the carbon cycle, a group can represent a tree that "breathes" CO2 from the atmosphere, a bird that eats the tree's seed and releases CO2 when flying, and a river that dissolves the CO2, forming carbonates that will be used by algae for photosynthesis.

   This playful and interactive activity allows students to visualize and better understand the processes of biogeochemical cycles, while developing teamwork and communication skills.

2. Debate Activity (5 - 7 minutes): After the presentations, the teacher should lead a debate among the groups, where each one will have the opportunity to explain their play and answer questions from other students. The objective of this debate is to deepen students' understanding of biogeochemical cycles and their importance for environmental sustainability, as well as to encourage the exchange of ideas and critical thinking.

3. Concept Map Activity (5 - 6 minutes): Finally, the teacher should ask students, in their groups, to create a concept map representing the biogeochemical cycles. The map should include the main components of each cycle (chemical elements, processes, and compartments), as well as the connections between them. This activity allows students to review and consolidate the learned content, while developing their organization and information visualization skills.

   Concept maps can be created on paper, cardboard, or using digital tools such as MindMeister or Coggle. The teacher should move around the room, assisting the groups and clarifying doubts.

These practical and dynamic activities allow students to learn in a meaningful and contextualized way, while developing essential skills for their education, such as critical thinking, communication, teamwork, and information organization.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes): The teacher should gather the whole class and promote a group discussion about the solutions or conclusions found by each team during the group activities. Each group will have a maximum of 3 minutes to share their puppet plays and their concept maps. During this discussion, the teacher should encourage students to ask questions and make comments, promoting a collaborative learning environment. The teacher should also provide brief feedback on the presentations, highlighting strengths and areas for improvement.

2. Connection with Theory (2 - 3 minutes): After the discussion, the teacher should make the connection between the practical activities carried out and the theory presented in the Introduction of the lesson. For example, he can show how the puppet plays represented the processes of biogeochemical cycles (such as photosynthesis, respiration, decomposition, etc.) and how the concept maps summarized the main elements and connections of these cycles. The teacher should also emphasize how understanding biogeochemical cycles is fundamental to understanding environmental phenomena and problems, such as global warming and pollution of ecosystems.

3. Final Reflection (2 - 3 minutes): Finally, the teacher should propose that students reflect for a minute on the following questions:

   • "What was the most important concept you learned today?"
   • "What questions have not been answered yet?"

   Students should write down their answers on a piece of paper, which will be collected by the teacher at the end of the lesson. These reflections will allow the teacher to assess students' understanding of the lesson's theme and identify possible gaps in learning, which can be addressed in future classes.

   Additionally, the teacher can propose that students reflect on how biogeochemical cycles are present in their daily lives and how their actions can affect these cycles. For example, he can ask: "How is your diet related to the nitrogen cycle? What can you do to reduce your environmental impact and preserve biogeochemical cycles?" This reflection allows students to apply what they have learned in the lesson to understand everyday environmental issues and to develop sustainable attitudes.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion by recalling the main points covered during the lesson. For example, he can highlight the definition of biogeochemical cycles, the main elements and processes of the nitrogen, carbon, and water cycles, and the importance of these cycles for environmental sustainability. This summary serves to reinforce students' learning and ensure that they have understood the key concepts of the lesson.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes): Next, the teacher should explain how the lesson connected theory, practice, and applications. For example, he can mention how the puppet theater and concept map activities allowed students to visualize and understand the processes of biogeochemical cycles, while the problem situations and group discussion encouraged the application of these concepts and reflection on their implications for the environment. The teacher should also highlight how the study of biogeochemical cycles has practical applications, such as understanding the effects of burning fossil fuels and the intensive use of fertilizers in agriculture, and promoting sustainable attitudes.

3. Additional Materials (1 - 2 minutes): The teacher should then suggest some additional materials for students who wish to deepen their knowledge of biogeochemical cycles. These materials may include books, scientific articles, educational videos, websites of environmental organizations, among others. For example, the teacher can recommend the documentary "Home," which explores the interaction between biogeochemical cycles and environmental sustainability. The teacher should also guide students on how to find and evaluate these materials, encouraging autonomous knowledge seeking.

4. Importance of the Subject for Daily Life (1 minute): Finally, the teacher should reinforce the importance of studying biogeochemical cycles for students' daily lives. For example, he can highlight how understanding these processes can help to comprehend natural phenomena, such as the occurrence of rain and soil formation, and to make more conscious and sustainable decisions regarding the use of natural resources and environmental preservation. The teacher should also emphasize that the knowledge acquired in the lesson is not limited to the academic sphere but can be applied in various everyday situations, contributing to the formation of more conscious and responsible citizens.

   Additionally, the teacher should encourage students to share what they have learned in the lesson with their families and friends, promoting the dissemination of knowledge and awareness of the importance of biogeochemical cycles for life on the planet.