Objectives (5 - 7 minutes)

1. Understand the definition of activation energy, its importance, and how it affects the speed of chemical reactions. Students should be able to explain the concept of activation energy in their own words and recognize its relevance in the context of chemical reactions.

2. Identify and describe the factors that can affect the activation energy of a reaction. Students should be able to list and explain factors such as temperature, concentration of reactants, and the presence of a catalyst that can influence activation energy.

3. Apply the concept of activation energy to predict the effect of changes in reaction conditions on the reaction rate. Students should be able to use their understanding of activation energy to make predictions about how the reaction rate will change if the reaction conditions are altered.

   Secondary Objectives:

   • Stimulate critical thinking and problem-solving. Through practical activities, students will be encouraged to apply the concept of activation energy to solve problems and predict outcomes.
   • Develop communication skills. Students will be invited to discuss and explain their answers and conclusions, promoting oral and written expression skills.
   • Foster curiosity and interest in Chemistry. Through practical and contextualized examples, the lesson aims to spark students' interest in the study of Chemical Kinetics.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher will start the lesson by briefly reviewing the concepts of chemical reactions, including the meaning of reactants and products, the idea that chemical reactions occur when bonds between atoms are broken and new bonds are formed, and that the speed of reactions can vary. This review is essential to ensure that students have a solid foundation for understanding the new content.

2. Problem Situation: The teacher will present two problem situations:

   a. "Why does food cook faster when we increase the stove temperature?"

   b. "Why doesn't food cook at room temperature, even when all the ingredients are present?"

   These questions serve to stimulate students' curiosity and prepare them for the introduction of the concept of activation energy.

3. Contextualization: The teacher will explain that the concept of activation energy is fundamental to understanding many everyday chemical phenomena, such as cooking food, fuel combustion, and the effectiveness of medications.

4. Attention Gain: To capture students' attention, the teacher may share some curiosities or practical applications of the activation energy concept:

   a. "Did you know that activation energy is one of the reasons why life on Earth is possible? If chemical reactions occurred very slowly, the biological processes that sustain life would not be possible."

   b. "Have you ever wondered why fireworks in fireworks displays are so bright and fast? This happens because the gunpowder, which is the reactant, has a very high activation energy, causing the reaction to release a large amount of energy in a short period of time."

Development (20 - 25 minutes)

1. Activity 'The Chemical Kitchen' (10 - 12 minutes)

   This activity involves a practical simulation of the activation energy concept, where students will 'cook' different foods on 'stoves' at various temperatures.

   a. Material Preparation: The teacher should prepare small quantities of different foods, such as potatoes, pasta, and rice, and 'stoves' at different temperatures. The 'stoves' can be represented by plastic cups, where the temperature is controlled by the amount of hot water added.

   b. Activity Development: Students will be divided into groups, and each group will receive a type of food and two 'stoves' at different temperatures. They must record the temperature of each 'stove' and the time required for the food to be ready to eat.

   c. Discussion and Analysis: After completing the activity, the groups should share their results with the class. The teacher will lead a discussion on how the temperature change (representing activation energy) affected the cooking time of the food (representing the reaction rate).

2. Activity 'The Catalyst Effect' (10 - 12 minutes)

   In this activity, students will observe how the presence of a catalyst can affect the speed of a reaction.

   a. Material Preparation: The teacher should prepare two transparent jars containing hydrogen peroxide and a solution of potassium permanganate. In one of the jars, the teacher should add a piece of liver, which will serve as a catalyst.

   b. Activity Development: Students, again divided into groups, will receive a set of materials. They should observe the reaction that occurs when hydrogen peroxide is added to the potassium permanganate solution in both jars and record their observations.

   c. Discussion and Analysis: After completing the activity, the groups should share their observations with the class. The teacher will lead a discussion on how the presence of the catalyst (the liver) affected the reaction rate (effervescence).

3. Activity 'The Unknown Reaction' (5 - 7 minutes)

   This activity is a challenge for students to apply what they have learned about activation energy to predict the effect of a change in reaction conditions.

   a. Material Preparation: The teacher should prepare a set of 'ingredients' (common substances found in a chemistry laboratory) and a set of 'reaction conditions' (temperature, concentration, presence of a catalyst, etc.) that can be altered.

   b. Activity Development: Students, still in their groups, will receive an 'ingredient' and a 'reaction condition.' They should use what they have learned about activation energy to predict if the reaction will occur, and if so, at what speed.

   c. Discussion and Analysis: After completing the activity, the groups should share their predictions with the class. The teacher will provide feedback and clarifications as needed and discuss the correct answers.

These activities provide students with the opportunity to explore and experiment with the concept of activation energy in a practical and engaging way, developing their critical thinking and problem-solving skills.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes)

   The teacher should facilitate a group discussion where each team shares their solutions, conclusions, and difficulties encountered during the activities. This allows students to learn from each other, reinforce their understanding of the activation energy concept, and develop communication and collaboration skills.

   a. Each group should have up to 3 minutes to present their observations and conclusions. The teacher should guide the discussion by asking questions to stimulate reflection and deepen students' understanding.

   b. During the presentations, the teacher should emphasize the importance of explaining the reasoning behind their predictions or conclusions, rather than just presenting the final result.

2. Connection to Theory (2 - 3 minutes)

   After the presentations, the teacher will review the theoretical concepts discussed during the lesson and how they connect to the practical activities. The teacher should emphasize how the concept of activation energy was applied in the different experimental situations and how the observed results are consistent with the theory.

   a. The teacher should highlight how activation energy affects the speed of reactions and how changes in reaction conditions, such as temperature and the presence of a catalyst, can affect activation energy and, consequently, the reaction rate.

   b. The teacher should reinforce the importance of understanding the theory behind practical activities so that students can apply their knowledge in new situations and solve problems more effectively.

3. Individual Reflection (2 - 3 minutes)

   To conclude the lesson, the teacher should encourage students to reflect individually on what they have learned. The teacher should ask questions that prompt students to think about the relevance of the content learned, the practical applications of the activation energy concept, and any remaining questions they may have.

   a. The teacher can ask questions such as: 'What was the most important concept you learned today?', 'How can you apply what you learned about activation energy in your daily life?' and 'What questions do you still have about activation energy?'

   b. The teacher should encourage students to write down their answers, as this can be useful for later review and for assessing students' understanding of the topic.

This Return process is crucial for consolidating learning, clarifying any doubts, and preparing students for independent study of the topic.

Conclusion (5 - 7 minutes)

1. Summary and Recapitulation: The teacher should start the Conclusion of the lesson by summarizing the main points covered. This includes the definition of activation energy, its importance in the speed of chemical reactions, and the factors that can affect it, such as temperature, concentration of reactants, and the presence of a catalyst. The teacher can do this through a verbal or visual summary, such as a board or slide. (1 - 2 minutes)

2. Theory-Practice Connection: Next, the teacher should highlight how the practical activities carried out in the lesson helped to illustrate and apply the theory of activation energy. The teacher can briefly review the main observations or conclusions of the students and how they relate to the theoretical concept. This will help reinforce students' understanding of the topic. (1 - 2 minutes)

3. Additional Materials: The teacher should suggest additional resources for students to deepen their knowledge of activation energy. This may include textbooks, educational videos online, virtual simulations, and chemistry websites. The teacher can share these resources in an email or online learning platform so that students can easily access them. (1 minute)

4. Everyday Applications: To conclude, the teacher should highlight some practical applications of the activation energy concept in everyday life. This may include examples such as cooking food, the effectiveness of medications, fuel combustion, and the reaction of gunpowder in fireworks. The teacher can encourage students to observe these phenomena in their daily lives, connecting the theory they learned with the real world. (1 - 2 minutes)

5. Question and Answer Session: If time allows, the teacher can open a brief question and answer session to clarify any final doubts from students. This can help ensure that students have a comprehensive and clear understanding of the activation energy concept. (Optional - depending on remaining time)

The Conclusion of the lesson is a crucial moment to consolidate learning, provide guidance for future studies, and demonstrate the relevance of the topic to students' everyday lives.