Objectives (5 - 7 minutes)

1. Understand the concept of magnetic force on charges and how it manifests in magnetism. This includes the notion that magnetic force is the force acting on a charged particle in motion in a magnetic field.

2. Develop the ability to calculate the magnetic force on charges. This involves applying the formulas of magnetic force in different situations, which may involve considering velocity, charge, and magnetic field.

3. Apply the acquired knowledge to solve practical problems involving magnetic force on charges. This means being able to interpret situations and apply the concepts and formulas learned to reach a solution.

Secondary Objectives:

• Promote critical and analytical thinking skills when working with complex physics concepts.

• Encourage active student participation through discussions and practical activities to enhance understanding and retention of the content.

Introduction (10 - 15 minutes)

1. Review of Previous Concepts:

   • The teacher starts the lesson by recalling basic concepts of magnetism, such as the fact that magnets have two poles (north and south) and that like poles repel each other, while opposite poles attract. (3 - 5 minutes)
   • Next, the teacher revisits the definition of magnetic field and how magnetic field lines behave around a magnet. (2 - 3 minutes)
   • Finally, the concept of electric charge and its relationship with magnetism is recapitulated, emphasizing that electric charges in motion are affected by magnetic fields. (2 - 3 minutes)

2. Problem Situations:

   • The teacher presents two situations to spark students' interest. The first one could be an electron in motion in a magnetic field, and the second one could be a magnet being attracted by another. (3 - 5 minutes)

3. Contextualization:

   • The teacher explains the importance of magnetism and magnetic force in our daily lives, citing examples such as the operation of electric motors, generators, and even magnetic resonance imaging devices. (2 - 3 minutes)

4. Engaging Students' Attention:

   • The teacher can tell the story of how magnetism was discovered, mentioning the ancient Greek people and their observations of the magnetic properties of magnetite. (2 - 3 minutes)
   • Then, the teacher can share some curiosities, such as the fact that compasses, which use the property of magnetism to indicate north, were invented by the Chinese over a thousand years ago. Another interesting curiosity is that the Earth's magnetic field is constantly changing, and scientists believe this may indicate a reversal of magnetic poles. (2 - 3 minutes)

This Introduction aims to situate students in the lesson's theme, review necessary concepts for understanding the topic, and spark their interest through problem situations, contextualization, and curiosities.

Development (20 - 25 minutes)

1. Theory on Magnetic Force on Charges (5 - 7 minutes)

1.1. Definition of Magnetic Force: - The teacher starts the theoretical part by explaining that magnetic force is the force acting on a charged particle in motion in a magnetic field. - He emphasizes that, unlike electric force, magnetic force does not do work on a charged particle, as magnetic force is always perpendicular to the particle's motion.

1.2. Magnetic Force Formula: - Next, the teacher presents the magnetic force formula (F = qvBsinθ), explaining each term. - He clarifies that F is the magnetic force, q is the particle's charge, v is the particle's velocity, B is the magnetic field's magnitude, and θ is the angle between the particle's velocity and the magnetic field.

1.3. Direction of Magnetic Force: - The teacher discusses the direction of magnetic force, stating that it is always perpendicular to the plane defined by the particle's velocity and the magnetic field. - He can illustrate this with a diagram and reinforce that magnetic force never causes the particle to change speed, only altering its velocity's direction.

2. Practical Examples of Magnetic Force Application (10 - 12 minutes)

2.1. Applications in Electric Motors: - The teacher explains how magnetic force is crucial for the operation of electric motors, widely used in various devices and vehicles. - He briefly describes the process in which magnetic force acts on electric charges in a motor, generating circular motion.

2.2. Applications in Generators: - Next, the teacher discusses how magnetic force is also fundamental in generators, which convert mechanical energy into electrical energy. - He explains that in these devices, magnetic force is responsible for generating an induced electric current.

2.3. Applications in Magnetic Resonance Imaging: - Finally, the teacher mentions how magnetic force is employed in medicine, specifically in magnetic resonance imaging devices. - He explains that these devices use magnetic force to create detailed images of the human body's interior, aiding in the diagnosis of various medical conditions.

3. Exercise Resolution (5 - 6 minutes)

3.1. The teacher hands out a series of exercises involving the calculation of magnetic force on charges. 3.2. He guides students to solve the exercises in groups, encouraging collaboration and discussion among them. 3.3. The teacher circulates around the room, clarifying doubts and providing guidance as needed.

This lesson's Development allows students to understand the theory behind magnetic force on charges and apply it to practical examples. Additionally, solving exercises in groups promotes interaction among students and the development of problemsolving skills.

Return (8 - 10 minutes)

1. Content Summary (3 - 4 minutes):

   • The teacher begins this stage by giving a brief summary of the main points covered during the lesson. He may recall the definition of magnetic force, the formula for calculating magnetic force, the direction of this force, and examples of its application in electric motors, generators, and magnetic resonance imaging.
   • He may also revisit the problem situations presented in the lesson's Introduction and check if students are now able to understand and explain the phenomenon presented.

2. Learning Verification (2 - 3 minutes):

   • The teacher can then ask students to briefly share what they learned during the lesson. For example, he can inquire how they would describe magnetic force on charges or how they could calculate this force in a specific situation.
   • The teacher should pay attention to students' answers, clarifying doubts and reinforcing concepts as necessary.

3. Reflection on Content Application (2 - 3 minutes):

   • The teacher should then guide students in reflecting on the practical application of the learned content. He can ask, for instance, how understanding magnetic force on charges could be useful in their daily lives or future careers.
   • The teacher can also question students about other applications of magnetism and magnetic force that were not addressed during the lesson, encouraging them to think critically about the topic.

4. Feedback and Closure (1 - 2 minutes):

   • Finally, the teacher should provide overall feedback on students' participation and performance, praising effort and dedication and offering suggestions for improvements if necessary.
   • The teacher can then conclude the lesson, reinforcing the importance of magnetism and magnetic force in our lives and encouraging students to continue exploring the topic on their own.

The Return is a crucial stage to ensure that students have understood the concepts presented during the lesson and to promote reflection on the applicability of these concepts in different contexts. Additionally, interacting with students during this stage allows the teacher to assess the effectiveness of his approach and make adjustments as needed.

Conclusion (5 - 7 minutes)

1. Recapitulation of Contents (2 - 3 minutes):

   • The teacher starts the Conclusion by summarizing the main points covered during the lesson. He reaffirms the definition of magnetic force, the formula for calculating magnetic force, the direction of this force, and examples of its application in electric motors, generators, and magnetic resonance imaging.
   • He may also recall the problem situations presented in the lesson's Introduction and check if students are now able to understand and explain the phenomenon presented.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes):

   • The teacher makes a connection between the theory presented and the practical applications discussed during the lesson. He emphasizes how understanding magnetic force is essential to comprehend the operation of various devices and technologies present in our daily lives.
   • He may also highlight how solving the exercises allowed students to apply the theory in a practical manner, reinforcing the importance of active and contextualized learning.

3. Suggestion of Supplementary Materials (1 - 2 minutes):

   • The teacher suggests some additional materials for students who wish to deepen their knowledge of magnetism and magnetic force. These materials may include explanatory videos, interactive simulations, educational websites, and reference books.
   • For example, he can recommend a video that visually and intuitively explains the action of magnetic force in an electric motor, or a website with a simulation that allows students to explore how magnetic force varies according to charge, velocity, and magnetic field.

4. Importance of Magnetism in Daily Life (1 minute):

   • Finally, the teacher highlights the importance of magnetism in our lives. He may mention, for instance, how magnetism is essential for generating energy in hydroelectric, thermal, and nuclear power plants, or how magnetic resonance imaging devices are used in medicine to diagnose a wide range of health conditions.
   • He concludes the lesson by reinforcing the idea that, although it may seem like an abstract concept, magnetism and magnetic force are present in numerous situations in our daily lives, becoming essential for understanding the world around us.

The Conclusion is a crucial stage to consolidate students' learning, reinforce the connection between theory and practice, and encourage autonomous exploration of the topic. Additionally, by emphasizing the relevance of magnetism in our lives, the teacher helps spark students' interest and curiosity, motivating them to continue learning about the subject.