Objectives (5 - 7 minutes)

1. Understanding Coulomb's laws for electric forces: The teacher should explain how Coulomb's laws describe the interaction between two electric charges and how the intensity of the electric force varies with the distance between the charges. Students should be able to apply these laws to calculate the electric force between two charges.

2. Solving problems of electric forces: Students should be able to apply Coulomb's laws to solve problems involving the determination of the electric force between two charges. To achieve this goal, the teacher should provide a series of practical examples and guide students in step-by-step resolution.

3. Understanding the difference between electric forces and electric fields: The teacher should clarify the difference between electric forces and electric fields. Students should understand that the electric force is the result of an electric field acting on an electric charge, and that an electric field is a region of space around an electric charge or a set of electric charges in which another electric charge experiences an electric force.

Secondary objectives:

1. Develop critical thinking skills: By solving problems of forces and electric fields, students will have the opportunity to develop their critical, analytical, and problem-solving skills.

2. Promote active learning: The teacher should encourage students to actively participate in the class by asking questions, discussing the presented concepts, and solving problems in groups.

Introduction (10 - 15 minutes)

1. Review of previous concepts: The teacher should start the class by reviewing the concepts of electric charge and interaction between charges, which were studied in previous classes. This can be done through a brief theoretical review or by conducting a simple experiment to demonstrate the attraction and repulsion between charges of the same and opposite signs.

2. Problem situations: After the review, the teacher should present two problem situations involving forces and electric fields. For example:

   • "Imagine you have two electric charges, one with a positive charge and the other with a negative charge. If you increase the distance between them, what happens to the force of attraction or repulsion between them?"

   • "Now, imagine you have an electric charge and want to know if there is an electric field around it. How can you determine that?"

   The purpose of these situations is to arouse students' interest in the subject and encourage them to think about the questions that will be addressed in the class.

3. Contextualization: The teacher should then contextualize the importance of studying forces and electric fields, explaining how these concepts are fundamental to understanding everyday electrical phenomena, such as static electricity and the operation of electronic devices.

4. Introduction to the topic: To introduce the topic in an engaging way, the teacher can present two curiosities:

   • "Did you know that electric force is one of the four fundamental forces of nature? It is responsible for the interaction between charged particles, and without it, matter could not exist as we know it."

   • "Another interesting curiosity is that electric fields can be invisible, but their effects can be easily observed. For example, when you comb your hair and the comb is attracted to your hand, this is due to the action of an electric field."

   By the end of this Introduction, students should be motivated to learn more about Coulomb's laws, electric forces, and electric fields.

Development (20 - 25 minutes)

1. Presentation of theory (10 - 12 minutes): The teacher should start the theory presentation by explaining Coulomb's laws, which describe the interaction between two electric charges. They should emphasize that the electric force between two charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. The teacher can use the formula F = k * (|q1| * |q2|) / r^2 to illustrate this relationship.

   • Example 1: The teacher can present a practical example to illustrate the application of Coulomb's laws. For instance, they can ask students to calculate the electric force between two charges, one with a charge of 2C and the other with a charge of -3C, separated by a distance of 4m. The teacher should guide students in solving the problem, showing how to substitute the values in the formula and calculate the electric force.

   • Example 2: The teacher can present a second example, but this time with charges of the same sign. For example, they can ask students to calculate the electric force between two charges, both with a charge of 5C, separated by a distance of 10m. The goal of this example is to show that charges of the same sign repel each other, and the electric force is negative.

2. Discussion and clarification of doubts (5 - 7 minutes): After the theory presentation, the teacher should open the floor for questions and clarification of doubts. They should ensure that students have understood Coulomb's laws and how to apply them to solve problems of electric forces.

3. Introduction to the electric field (5 - 6 minutes): Next, the teacher should introduce the concept of an electric field. They should explain that an electric field is a region of space around an electric charge or a set of electric charges in which another electric charge experiences an electric force. The teacher can use the formula E = F / q to illustrate the relationship between electric force and electric charge in an electric field.

   • Example 3: The teacher can ask students to calculate the electric field created by a charge of 4C at a distance of 5m from it. The goal of this example is to show how to calculate the electric field from the electric force and the electric charge.

4. Solving problems of electric fields (5 - 7 minutes): Finally, the teacher should guide students in solving problems involving electric fields. They should provide practical examples and explain step by step how to calculate the electric field in each case.

   • Example 4: The teacher can ask students to calculate the electric field at the midpoint between two equal charges with the same sign, separated by a distance d. The goal of this example is to show that the electric field of two equal charges with the same sign cancels out at the midpoint between them.

   • Example 5: The teacher can present a second example, but this time with two charges of opposite signs. For example, they can ask students to calculate the electric field at the midpoint between two equal charges with opposite signs, separated by a distance d. The goal of this example is to show that the electric field of two charges with opposite signs adds up at the midpoint between them.

By the end of this Development, students should have understood Coulomb's laws, be able to solve problems of electric forces, and calculate electric fields.

Return (8 - 10 minutes)

1. Review and Recapitulation (2 - 3 minutes): The teacher should start the Return by reviewing the main concepts presented during the class. This can be done through an oral summary, recalling Coulomb's laws, the relationship between electric forces and electric fields, and how to solve problems involving these concepts. Additionally, the teacher should reinforce the importance of these concepts for understanding everyday electrical phenomena.

2. Connection with the real world (2 - 3 minutes): Next, the teacher should establish connections between the concepts learned and real-world situations. For example, they can mention how understanding Coulomb's laws and electric fields is essential for the operation of electronic devices, such as cell phones and computers. Additionally, the teacher can briefly discuss the importance of these concepts for the study of other areas of physics, such as electromagnetism and optics.

3. Individual reflection (2 - 3 minutes): The teacher should then propose that students reflect individually on what they learned in the class. This can be done through questions like:

   1. "What was the most important concept you learned today?"
   2. "What questions have not been answered yet?"

   Students should be encouraged to write down their answers, as this can facilitate the review and further study process.

4. Sharing and discussion (2 - 3 minutes): Finally, the teacher should promote a classroom discussion where students are invited to share their reflections. The teacher should be open to hearing students' doubts and difficulties, and clarify any misunderstandings. Additionally, the teacher can use this opportunity to reinforce the most important concepts and encourage students to continue studying the subject.

By the end of this Return, students should have consolidated their knowledge of Coulomb's laws, electric forces, and electric fields, and should be prepared to apply these concepts in practical situations and in the study of other physics topics.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion of the class by summarizing the main points covered during the class. They should recall Coulomb's laws, the relationship between electric forces and electric fields, and how to solve problems involving these concepts. The teacher should emphasize the importance of these concepts for understanding everyday electrical phenomena and for the study of other areas of physics.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes): Next, the teacher should emphasize how the class connected theory, practice, and applications. They should remind students of how the theory of Coulomb's laws was applied to solve problems of electric forces, and how the concept of an electric field was introduced and applied in problem-solving. Additionally, the teacher should reinforce the practical applications of these concepts, mentioning again the example of the operation of electronic devices.

3. Supplementary Material (1 - 2 minutes): The teacher should then suggest some supplementary materials for students who wish to deepen their knowledge. They can recommend physics books, educational websites, YouTube videos, and simulation apps. Additionally, the teacher can propose some extra exercises for students to practice at home.

4. Importance of the Subject (1 minute): Finally, the teacher should emphasize the importance of the subject for everyday life. They should explain that, although electric forces and electric fields may seem abstract, they are fundamental to our understanding of how the world around us functions. For example, the teacher can mention how electricity, based on the interaction between electric charges and electric fields, is essential for our modern life, from lighting to communication and transportation.

By the end of this Conclusion, students should have understood the importance of the concepts learned in the class and should be motivated to continue studying the subject.