Objectives (5 - 7 minutes)

1. Understand the difference between reversible and irreversible transformations: Students should be able to distinguish between transformations that can be undone (reversible) and those that cannot (irreversible). This may include simple examples, such as drawing and erasing on a blackboard (reversible) versus burning a piece of paper (irreversible).

2. Identify different types of reversible and irreversible transformations: Students should be able to identify and name different types of reversible and irreversible transformations, both in terms of physical changes (such as melting ice and solidifying water) and chemical changes (such as cooking food and burning wood).

3. Apply the concept of reversible and irreversible transformations in everyday situations: Students should be able to apply the concept of reversible and irreversible transformations in everyday situations. For example, they may consider how their clothes dry after being washed (reversible transformation) or how the leaves of a tree change color in the autumn (irreversible transformation).

Secondary Objectives:

• Stimulate critical thinking: Students should be encouraged to think about the transformations that occur around them and to consider whether these transformations are reversible or irreversible.

• Develop observation skills: During the lesson, students will be invited to observe and describe different transformations. This will help develop their observation skills, which are fundamental to the study of science.

Introduction (10 - 12 minutes)

1. Review of concepts: The teacher starts the lesson by briefly reviewing concepts that students should have encountered in previous classes. This may include the definition of matter, the difference between solids, liquids, and gases, and the idea that matter can change shape or state. This review serves as a starting point for the new topic that will be introduced.

2. Problem situations: The teacher proposes two problem situations related to the theme of the lesson:

   • Situation 1: "Have you noticed that when we draw with a pencil on paper, we can erase the drawing and start over, but if we burn the paper, it doesn't return to its original state? Why does this happen?"
   • Situation 2: "When we put an ice cube in a glass, it melts and turns into water. If we put that glass in the refrigerator, the water turns back into ice. Is this transformation reversible or irreversible?"

3. Contextualization: The teacher explains that understanding reversible and irreversible transformations is important for everyday life. For example, by understanding that burning paper is an irreversible transformation, students can be more careful when handling flammable objects. Additionally, knowledge about reversible and irreversible transformations is essential in the study of many areas of science, such as chemistry and physics.

4. Capturing students' attention: To spark students' interest, the teacher can share some curiosities or interesting facts about the topic. For example:

   • Curiosity 1: "Did you know that the transformation of water into ice and ice into water is one of the few transformations that occur in nature and are completely reversible? This means that if we have ice, we can turn it into water, and if we have water, we can turn it into ice, as many times as we want, without losing any of the materials."
   • Curiosity 2: "Have you heard of the water cycle? It is an example of a transformation that occurs in nature and involves several reversible transformations. Water evaporates, forms clouds, rains, and then evaporates again."

This introduction helps to arouse students' interest in the topic, making learning more engaging and meaningful.

Development (20 - 25 minutes)

1. Theoretical explanation of reversible and irreversible transformations (5 - 7 minutes)

   • The teacher starts the theoretical part by presenting the definition of reversible and irreversible transformations.
   • To facilitate students' understanding, the teacher uses practical and everyday examples to illustrate each type of transformation. For example, how ice turns into water and vice versa (reversible) and how burnt paper cannot return to its original state (irreversible).
   • The teacher emphasizes that transformations are part of nature and that many of them can be reversed, but some are permanent, and these are called irreversible transformations.

2. Practical activity: Observing and identifying transformations (10 - 12 minutes)

   • The teacher proposes a series of practical activities where students can observe different types of transformations and identify whether they are reversible or irreversible.
   • The first activity can be the demonstration of the transformation of water into ice and ice into water. The teacher prepares some ice cubes and places them in a glass, and the students observe what happens. Then, the teacher puts the glass in the refrigerator, and the students observe again. The teacher asks the students if this transformation is reversible or irreversible.
   • The second activity can be burning a piece of paper. The teacher lights one end of the paper, and the students observe what happens. The teacher asks the students if this transformation is reversible or irreversible.
   • The teacher can propose other similar activities, depending on the available time and the students' receptivity.

3. Group discussion about the activities (5 - 6 minutes)

   • After the activities, the teacher gathers all students in a circle for a group discussion.
   • The teacher asks students to share their observations and conclusions about the transformations they observed and whether they are reversible or irreversible.
   • The teacher also encourages students to make connections between the practical activities and the theory presented earlier. For example, by asking: "How does the transformation we observed from ice to water and back to ice relate to what we discussed about reversible and irreversible transformations?"

4. Conclusion of the activity with a moment of reflection (5 - 7 minutes)

   • To conclude the development stage, the teacher proposes a moment of individual reflection.
   • The teacher asks two simple questions for students to reflect on what they learned in the lesson:
     • Question 1: "Think of a transformation you observe at home or at school. Is it reversible or irreversible? Why?"
     • Question 2: "Think of a transformation that occurs in nature. Is it reversible or irreversible? Why?"
   • Students will have a minute to think, and then they can share their answers with the class if they wish.

This active and practical development allows students to apply what they have learned in real situations, strengthening their understanding of the concept of reversible and irreversible transformations.

Return (8 - 10 minutes)

1. Group discussion (3 - 4 minutes)

   • The teacher starts the return by gathering all students in a circle.
   • Each student who wanted to share their answers to the reflection questions will have the opportunity to do so. The teacher will encourage students to explain their reasoning and how they applied the concept of reversible and irreversible transformations in their answers.
   • The teacher can also select some of the observations and conclusions shared during the previous group discussion to reinforce the key concepts of the lesson.

2. Connection with theory (2 - 3 minutes)

   • Next, the teacher will highlight how the practical activities and group discussion connected theory with practice. He may recall the examples of reversible and irreversible transformations observed during the lesson and how these transformations relate to the theoretical concepts presented at the beginning of the lesson.
   • The teacher will clarify any doubts that may have arisen during the lesson and provide further explanations, if necessary, to ensure that all students have a solid understanding of the topic.

3. Final reflection (3 - 4 minutes)

   • To conclude the lesson, the teacher proposes that students reflect on what they have learned. He asks two questions to guide students' reflection:
     • Question 1: "What was most interesting to you in today's lesson? Why?"
     • Question 2: "How can you apply what you learned today about reversible and irreversible transformations in your daily life?"
   • Students will have a minute to think about the answers to these questions. Then, they will be invited to share their answers with the class if they wish.
   • The teacher will encourage students to continue observing the transformations around them and to think about whether these transformations are reversible or irreversible, which will help reinforce the learned concept.

This return is a crucial part of the lesson plan, as it allows the teacher to assess students' understanding of the topic and reinforce key concepts. Additionally, it offers students the opportunity to reflect on what they have learned, promoting autonomous learning and connecting the content to real life.

Conclusion (5 - 7 minutes)

1. Summary of the main points of the lesson (2 - 3 minutes)

   • The teacher starts the conclusion by recalling the main points of the lesson. He recaps the definition of reversible and irreversible transformations, and how students identified them in different situations.
   • He also recalls the practical examples observed during the lesson, such as the transformation of water into ice and ice into water (reversible) and the burning of paper (irreversible), in order to consolidate students' understanding of the topic.

2. Connection between theory, practice, and applications (1 - 2 minutes)

   • The teacher highlights how the lesson connected theory, practice, and applications. He emphasizes how the practical activities allowed students to directly observe reversible and irreversible transformations, and how these observations reinforced the theory presented.
   • He also mentions the practical applications of the concept of reversible and irreversible transformations, such as understanding why we cannot reverse the burning of paper and how we can transform water into ice and vice versa.

3. Additional materials for further study (1 - 2 minutes)

   • The teacher suggests some additional materials for students who wish to deepen their knowledge on the topic. This may include children's science books, educational videos online, and interactive games that explore the concept of transformations.
   • He may also suggest activities for students to do at home, such as observing and recording reversible and irreversible transformations that occur around them.

4. Importance of the topic for daily life and other disciplines (1 minute)

   • Finally, the teacher emphasizes the importance of the subject for students' daily lives and for other disciplines. He explains that understanding reversible and irreversible transformations can help students better understand the world around them and make more informed decisions.
   • He also mentions how the concept of reversible and irreversible transformations is relevant to other areas of science, such as chemistry and physics.

This conclusion helps to consolidate students' learning, while providing them with resources to continue exploring the topic on their own. Additionally, it reinforces the relevance of the topic, making learning more meaningful for students.