Objectives (5 - 7 minutes)

1. Understand the concept of transformations: Students should be able to define and identify what transformations are, both reversible and irreversible. They should understand that transformations are changes that occur in objects or substances, which can be reversed or not.

2. Differentiate reversible and irreversible transformations: Students should be able to distinguish between reversible and irreversible transformations. They should be able to identify examples of each type of transformation and understand the differences between them.

3. Apply the concepts learned: Students should be able to apply the concepts of reversible and irreversible transformations in everyday situations. They should be able to identify and describe reversible and irreversible transformations that occur at home, at school, or elsewhere.

Introduction (10 - 15 minutes)

1. Review of previous content: The teacher starts by reminding students about the concept of change and transformation. They can discuss simple examples of transformations that students already know, such as the change from a caterpillar to a butterfly, the transformation of water into ice, among others. This serves to prepare the ground for the new information about reversible and irreversible transformations.

2. Problem situation 1: Melted ice: The teacher proposes a situation where a child puts an ice cube in a cup and leaves the cup on the table. The next day, the child checks the cup and the ice is no longer there. The teacher asks: 'What happened to the ice? Is this a reversible or irreversible transformation?'

3. Problem situation 2: Burnt food: The teacher proposes another situation where a child leaves a piece of bread in the toaster for a long time and it ends up burning. The teacher asks: 'What happened to the bread? Is this a reversible or irreversible transformation?'

4. Contextualization of the importance of the subject: The teacher explains that understanding reversible and irreversible transformations is important because it helps us understand the world around us. For example, if we understand that burning a piece of paper is an irreversible transformation, we will know that we cannot recover that piece of paper. Similarly, if we understand that water can turn into vapor and then return to water, we will know that we can use evaporation and condensation to obtain clean water.

5. Introduction to the topic: To arouse students' interest, the teacher can share some curiosities about reversible and irreversible transformations. For example, they can mention that the transformation of an egg into an omelette is an irreversible transformation, but the transformation of a caterpillar into a butterfly is a reversible transformation (the process can be reversed when the butterfly lays eggs that turn into caterpillars).

Development (20 - 25 minutes)

1. Activity 1: Ice and fire experiment (10 - 12 minutes)

   • In groups of up to 5 students, each receives an ice cube and an extinguished match.
   • The teacher instructs the students to observe what happens to the ice cube over time and what happens when they try to light the match.
   • After the observations, the teacher guides a group discussion, asking: 'What happened to the ice cube? Is this a reversible or irreversible transformation?' and 'What happened to the match? Is this a reversible or irreversible transformation?'

2. Activity 2: The water cycle (10 - 12 minutes)

   • The teacher explains that the water cycle is an example of reversible transformations.
   • Students, still in their groups, receive a sheet of paper, colored pens, and a cup of water.
   • The teacher instructs the students to draw and color the stages of the water cycle on the paper, while observing what happens to the water in the cup.
   • After the observations, the teacher guides a group discussion, asking: 'What happened to the water in the cup? Is this a reversible or irreversible transformation?'

3. Activity 3: Material transformations (10 - 12 minutes)

   • The teacher proposes that students, in their groups, take different objects (paper, plastic, wood, metal, etc.) and try to transform them in different ways (tear, crumple, burn, etc.).
   • The teacher instructs the students to observe what happens to each object during the transformations and whether these transformations are reversible or irreversible.
   • After the observations, the teacher guides a group discussion, asking: 'What happened to the paper when you burned it? And when you crumpled it? Were these transformations reversible or irreversible? Why?'

During these activities, the teacher should circulate around the room, clarifying doubts, encouraging participation, and ensuring that all students are involved. They should also ask questions that stimulate students to think critically about the transformations they are observing and to apply the concepts they have learned.

Return (10 - 12 minutes)

1. Group discussion (5 - 6 minutes): The teacher gathers all students in a large circle and starts a group discussion. They ask each group what they observed during the activities, which transformations they considered reversible and irreversible, and why. The teacher should encourage the participation of all students and ensure that all voices are heard. They can also add additional information to enrich the discussion.

2. Connection with theory (2 - 3 minutes): After the discussion, the teacher reinforces the concepts of reversible and irreversible transformations. They can ask students if they can think of more examples of transformations that are reversible or irreversible. They can also recall the examples given during the activities and ask students if they can explain why these transformations are reversible or irreversible.

3. Individual reflection (3 - 4 minutes): To end the lesson, the teacher proposes that students reflect on what they have learned. They ask two simple questions, which students can answer mentally:

• 'What was the transformation you enjoyed observing the most today? Was it reversible or irreversible?'
• 'Can you think of a transformation that occurs every day in your home or school? Is it reversible or irreversible?'

During the return, the teacher should reinforce the importance of respecting the opinions of classmates and the diversity of ideas. They should also take the opportunity to praise the efforts of the students, encourage them to continue exploring and learning, and reinforce that making mistakes is part of the learning process.

Conclusion (5 - 7 minutes)

1. Summary of contents (2 - 3 minutes): The teacher starts the conclusion by recalling the main points of the lesson. They recap that transformations are changes that occur in objects or substances and can be reversible or irreversible. They reinforce that reversible transformations are those that can be undone and that irreversible transformations are those that cannot be undone. They can use examples from the activities to illustrate these concepts.

2. Connection between theory and practice (1 - 2 minutes): The teacher explains that during the lesson, students had the opportunity to observe several transformations and classify them as reversible or irreversible. They emphasize that this practical experience helps reinforce the theory and makes learning more meaningful.

3. Extra materials (1 minute): The teacher suggests some extra materials for students who wish to deepen their knowledge on the subject. They can recommend children's books that address transformations in nature, educational videos online about the water cycle, or simple experiments that students can do at home to observe more reversible and irreversible transformations.

4. Relevance of the subject (1 minute): Finally, the teacher highlights the importance of understanding reversible and irreversible transformations in everyday life. They explain that this knowledge can help students better understand the processes that occur around them, such as the change in the state of water, the transformation of food during cooking, among others. They also emphasize that understanding these transformations can be useful in practical activities, such as cooking, taking care of plants, or even fixing broken toys.

During the conclusion, the teacher should maintain a positive and encouraging tone, reinforcing that students did a great job exploring and learning about reversible and irreversible transformations. They should also emphasize that learning is a continuous process and that students can always seek more information and make more discoveries.