Objectives (5 - 7 minutes)

• Understand the concept of solution: Students should be able to explain what a solution is and how it is formed from the mixture of two or more components.

• Identify types of solutions: Students should be able to recognize the different types of solutions, such as solid, liquid, and gas solutions, and understand their characteristics.

• Differentiate solutions from mixtures without reaction: Students should be able to distinguish between solutions and mixtures that do not generate a chemical reaction, understanding that not every mixture results in a solution.

Secondary Objectives:

• Develop practical skills: Students should be able to apply the theoretical concepts learned in practice through simple experiments.

• Stimulate critical thinking: Students should be encouraged to think critically about the concepts learned, relating them to everyday situations and other chemistry topics already studied.

Introduction (10 - 15 minutes)

• Review of related contents: The teacher should start the lesson by quickly reviewing basic chemistry concepts such as atoms, elements, compounds, mixtures, and chemical reactions. This review can be done through questions directed at the students, encouraging active participation.

• Problem situations: The teacher can then propose two problem situations to instigate the students' curiosity and prepare them for the content to be covered. For example, the teacher can ask: "Why does sugar dissolve in water but not in oil?" or "What happens when you mix salt and sand?". These questions serve to highlight the difference between a solution and a mixture without reaction.

• Contextualization: The teacher should explain the importance of studying solutions and mixtures without reaction, showing their presence in various everyday situations. For example, the teacher can mention the preparation of juices, where sugar dissolves in water, or the preparation of salads, where oil and vinegar do not mix.

• Introduction to the topic: To capture the students' attention, the teacher can share some curiosities or stories related to the theme. For example, the teacher can tell the story of how the discovery of salt solubility in water led to the invention of the refrigerator, or mention the curiosity that olive oil is a solution of various substances, including antioxidants and vitamins.

• Presentation of the topic: Finally, the teacher should formally introduce the topic of the lesson, explaining that the focus will be on the study of solutions and mixtures without reaction. The teacher should make it clear that, by the end of the lesson, students will be able to identify and differentiate these two concepts.

Development (20 - 25 minutes)

• Experimentation Activity - "The Magic of Sugar and Sand" (10 - 12 minutes)

  1. Experiment Preparation: The teacher should prepare in advance two transparent bottles, one with water and sugar and another with water and sand. The quantities should be sufficient for the students to clearly see what is happening. The teacher should also have a spoon on hand to mix the mixtures.

  2. Experiment Demonstration: The teacher should perform the experiment demonstration in front of the class. First, he should add a quantity of sugar to the water and stir until the sugar dissolves completely, forming a solution. Then, he should add a quantity of sand to the water and stir, showing that the sand does not dissolve, remaining as a mixture without reaction.

  3. Discussion of Results: After the demonstration, the teacher should lead a discussion in the classroom, questioning the students about what they observed. He should guide the discussion so that students realize the difference between a solution (sugar) and a mixture without reaction (sand).

  4. Repetition of the Experiment by the Students: Now it's the students' turn to perform the experiment. The teacher should divide the class into groups and distribute the materials. The students should follow the same steps as the demonstration, observing and discussing the results among themselves.

• Discussion Activity - "What is a Solution?" (5 - 7 minutes)

  1. Group Division and Card Distribution: The teacher should divide the class into groups and distribute a set of cards to each group. Each card should contain the name of a substance (for example, salt, sugar, alcohol, water, oil, sand, etc.).

  2. Discussion and Classification of Substances: The students, in their groups, should discuss and classify the substances into two groups: "substances that form solutions when mixed with water" and "substances that do not form solutions when mixed with water".

  3. Presentation and Discussion of Classifications: After the classification, each group should present their conclusions to the class. The teacher should moderate the discussion, correcting misconceptions and reinforcing the correct concepts.

• Problem Solving Activity - "Types of Solutions" (5 - 7 minutes)

  1. Problem Presentation: The teacher should present a problem for the students to solve in their groups. For example: "Imagine you have a mixture of water and sugar. If you heat the mixture until the water evaporates, what will remain? Why?". The teacher should ensure that the students clearly understand the problem before they start solving it.

  2. Problem Solving by the Students: The students, in their groups, should discuss and come up with a solution to the proposed problem. They should consider the concepts of solution and evaporation to arrive at the correct answer.

  3. Presentation of Solutions by the Groups: Each group should present their solution to the problem. The teacher should again moderate the discussion, correcting mistakes and reinforcing correct answers.

These activities are designed to actively engage students in the learning process, allowing them to explore the concept of solutions and mixtures without reaction in a practical and interactive way. Additionally, they stimulate critical thinking and collaboration among students.

Return (8 - 10 minutes)

• Group Discussion (3 - 4 minutes): After the conclusion of the activities, the teacher should gather all students for a group discussion. Each group should share the solutions they found for the proposed problems. The teacher should moderate the discussion, ensuring that all students have the opportunity to speak and clarify any doubts they may have. The objective of this discussion is to allow students to learn from each other and for the teacher to assess their understanding of the lesson's topic.

• 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 at the beginning of the lesson. He should highlight how the concepts of solution and mixture without reaction apply to the experiments and problems solved. Additionally, the teacher should answer any questions students may have about the theory.

• Individual Reflection (2 - 3 minutes): To conclude the lesson, the teacher should propose that students reflect individually on what they have learned. He should ask questions like: "What was the most important concept you learned today?" and "What questions do you still have about the topic?". Students should have a minute to think about their answers. After that, the teacher can ask some students to share their reflections with the class.

• Assessment (1 minute): Finally, the teacher should assess the students' progress during the lesson. He can do this by observing their participation in discussions and activities, or by reviewing their answers to the proposed problems. Based on this assessment, the teacher can plan adjustments for future lessons, if necessary.

This Return stage is crucial to consolidate students' learning and for the teacher to verify if the lesson's Objectives were achieved. Additionally, it allows students to express any doubts or difficulties they may have, which can guide the planning of future lessons.

Conclusion (5 - 7 minutes)

• Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion of the lesson by summarizing the main points covered. He should reinforce the concept of solution, explaining that it is a homogeneous mixture of two or more substances that do not react with each other. He should also recap the different types of solutions, such as solid, liquid, and gas solutions. Additionally, the teacher should highlight the difference between solutions and mixtures without reaction, recalling the experiments and activities carried out.

• Connection between Theory, Practice, and Applications (1 - 2 minutes): Next, the teacher should make the connection between the presented theory, the practical activities carried out, and the real-world applications. He should explain that practical activities, such as the experiment with sugar and sand, helped illustrate the theoretical concepts in a concrete and visual way. Additionally, he should mention that understanding these concepts is essential to comprehend a variety of everyday chemical phenomena, such as salt dissolution in water or the preparation of juices.

• Additional Materials (1 minute): The teacher should suggest additional study materials for students who wish to deepen their knowledge of solutions and mixtures without reaction. These materials may include videos, books, chemistry websites, and online activities. The teacher can also recommend that students practice more by solving problems related to the topic.

• Importance of the Subject for Everyday Life (1 - 2 minutes): Finally, the teacher should emphasize the importance of the learned subject for students' daily lives. He should explain that solutions and mixtures without reaction are present in many aspects of our daily lives, from food and beverage preparation to house cleaning. Additionally, he can mention that understanding these concepts is fundamental to comprehend many other chemistry topics, such as substance reactivity and the formation of new compounds.

• Lesson Closure (1 minute): To conclude the lesson, the teacher should thank the students for their participation and encourage them to continue studying the topic. He should also remind the students of the Objectives of the next lesson and what will be covered.