Objectives (5 - 7 minutes)

1. Understand the human excretory system: Students should be able to identify and describe the organs that make up the human excretory system and their respective functions. They should also be able to explain the importance of the excretory system for maintaining homeostasis in the human body.

2. Identify the main substances excreted by the human body: Students should be able to list and describe the main substances that are excreted by the human body through the excretory system. They should understand that these substances are waste products of metabolism that need to be eliminated to avoid harming the body.

3. Relate the excretory system to other systems of the human body: Students should be able to understand how the excretory system interacts with and depends on other systems of the human body, such as the circulatory system and the digestive system. They should be able to explain how excretion is a continuous process that occurs in conjunction with other bodily processes.

Secondary Objectives:

• Stimulate critical thinking: Throughout the lesson, students should be encouraged to make connections between the concepts learned and everyday situations, in order to develop critical thinking about the importance of the excretory system for human health.

• Foster active participation: Through practical activities and group discussions, students should be encouraged to actively participate in the lesson, sharing their ideas, questions and opinions on the subject.

Introduction (10 - 15 minutes)

1. Review of related content: The teacher begins the lesson by reminding students about the systems of the human body that have already been studied, with an emphasis on the circulatory and digestive systems. He can ask questions to check students' prior knowledge of these systems and how they are interconnected. (3 - 5 minutes)

2. Problem situations: The teacher proposes two hypothetical situations to arouse students' interest in the topic. The first situation could involve a person who is sweating a lot on a hot day and wants to understand why this happens. The second situation could involve a person who has drunk a lot of liquid and is going to the bathroom frequently, and wants to know why this occurs. (3 - 5 minutes)

3. Contextualization of the importance of the subject: The teacher explains that understanding the excretory system is essential for understanding how our body stays healthy. He can cite examples of diseases that affect the excretory system, such as kidney failure, and how these diseases can impact people's lives. In addition, he can mention the importance of hydration and healthy eating for the proper functioning of the excretory system. (2 - 3 minutes)

4. Gaining students' attention: To make the topic more appealing, the teacher can share curiosities about the excretory system. For example, he can mention that, on average, the human body produces about 1.5 liters of urine per day. Another curiosity is that the kidneys are so efficient that they can filter all the blood in the body about 400 times a day. (1 - 2 minutes)

5. Introduction of the topic: Finally, the teacher formally introduces the topic of the lesson - the excretory system. He explains that the excretory system is responsible for eliminating toxic and excess substances from our body, maintaining our health. He also points out that the excretory system is not limited to the kidneys, but includes several other organs, such as the skin and lungs. (1 - 2 minutes)

Development (20 - 25 minutes)

1. Activity "The Water Cycle in the Human Body" (10 - 12 minutes):

   • Activity description: In this activity, students will be divided into groups and will receive a large sheet of paper, colored pens and stickers with drawings of organs of the excretory system. They will draw a large cycle, representing the "Water Cycle in the Human Body". The cycle should include the stages of water ingestion, absorption in the digestive tract, circulation through the circulatory system, filtration by the kidneys, urine formation, excretion by the bladder and elimination from the body. The drawings of the organs should be pasted on the corresponding parts of the cycle.

   • Step-by-step of the activity:

     1. The teacher distributes the material and explains the activity.
     2. Students, in their groups, discuss and plan the design of the cycle.
     3. They draw the cycle and paste the drawings of the organs.
     4. After completion, each group presents its cycle to the class, explaining each stage.
     5. The teacher makes comments and clarifies doubts.

2. Activity "The Life of a Nephron" (10 - 12 minutes):

   • Activity description: In this activity, students continue in their groups and receive a set of cards with words representing different stages of the blood filtration process in the kidneys (e.g. filtration, reabsorption, secretion, urine formation). They also receive a large paper poster with an image of a nephron, the functional unit of the kidneys. The objective is for them to place the cards in the correct order along the nephron, explaining each stage.

   • Step-by-step of the activity:

     1. The teacher distributes the material and explains the activity.
     2. Students, in their groups, discuss and plan the order of the cards.
     3. They place the cards on the nephron, explaining each stage.
     4. After completion, each group presents its nephron to the class, explaining the stages.
     5. The teacher makes comments and clarifies doubts.

3. Discussion and Conclusion (5 - 8 minutes):

   • Activity description: After the two activities, the teacher leads a classroom discussion. He can ask questions such as: "What was the most important stage of the water cycle in the human body?", "Why is urine formation a crucial process for maintaining homeostasis?", "What are the similarities and differences between the water cycle in the human body and the water cycle in nature?".

   • Step-by-step of the activity:

     1. The teacher initiates the discussion, asking questions and listening to students' answers.
     2. He makes comments, clarifies doubts and reinforces the main points.
     3. The teacher concludes the lesson, reinforcing the importance of the excretory system for human health and encouraging students to continue exploring the topic on their own.

Feedback (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes): The teacher asks each group to share the solutions or conclusions they reached during the activities. Each group has a maximum of 3 minutes to present. The teacher should ensure that all groups have the opportunity to speak and encourage the participation of all students. During the presentations, the teacher can ask questions to stimulate students' critical thinking and to check if they understood the concepts covered. For example, the teacher might ask: "Why did you place the reabsorption step before the urine formation in the human body water cycle?" or "What is the relationship between nephron activity and the amount of urine produced?".

2. Connection with Theory (2 - 3 minutes): After all the presentations, the teacher makes a recap of the activities, highlighting how they relate to the theory presented at the beginning of the lesson. He can, for example, remind that the kidneys are the main organs of the excretory system, responsible for filtering the blood and forming urine. He can also reinforce the importance of the circulatory system in excretion, since it is through it that the excreted substances are transported out of the body. The teacher should use examples from the activities to illustrate these concepts.

3. Individual Reflection (2 - 3 minutes): To conclude the lesson, the teacher suggests that students reflect for a minute on the following questions:

   1. What was the most important concept you learned today?
   2. What questions do you still have about the excretory system?

   The teacher can ask students to write down their answers on a piece of paper or in their notebooks. Then, he can ask some students to share their answers with the class. This can help the teacher identify which concepts need to be reinforced in future lessons and to clarify any remaining doubts of the students. The teacher should encourage students to be honest in their reflections and to express any difficulties they may be facing. He should reinforce that it is normal to have doubts and that the important thing is to be willing to learn and to seek answers to these doubts.

Conclusion (5 - 7 minutes)

1. Summary of the Contents (2 - 3 minutes): The teacher begins the Conclusion by recapping the main points covered in the lesson. He reinforces that the excretory system is responsible for eliminating toxic and excess substances resulting from metabolism from the human body. He emphasizes that the main organs of the excretory system are the kidneys, but that other organs, such as the skin and lungs, also contribute to excretion. In addition, the teacher reiterates that excretion is a continuous process that involves the interaction between several systems of the human body, such as the circulatory system and the digestive system.

2. Connection between Theory, Practice and Applications (1 - 2 minutes): Next, the teacher highlights how the lesson was able to connect theory, practice and applications. He mentions that the group activities allowed students to visualize and better understand the complex processes that occur in the excretory system. In addition, he recalls that the problem situations presented in the Introduction helped to contextualize the importance of the excretory system for human health. The teacher can also mention that the final reflection allowed students to apply what they learned to their own experiences and to question what they still did not fully understand.

3. Supplementary Materials (1 minute): The teacher suggests some additional study materials for students who wish to deepen their knowledge about the excretory system. He can recommend books, websites, videos and documentaries that address the topic in a clear and interesting way. The teacher can also indicate simple experiments that students can do at home to observe the functioning of the excretory system.

4. Relevance of the Subject (1 - 2 minutes): Finally, the teacher emphasizes the importance of the excretory system for everyday life. He explains that a proper understanding of the excretory system can help students to better understand their own body and to make healthy choices. For example, students can learn the importance of adequate hydration and a balanced diet for the proper functioning of the excretory system. In addition, the teacher can mention that a basic knowledge of the excretory system is essential for understanding certain diseases, such as kidney failure, and for taking preventive measures against these diseases.