Objectives (5 - 10 minutes)

1. Understand the concept of resistivity: Students should be able to define resistivity as an inherent property of a material that determines the ease with which electric current flows through it. Additionally, they should understand that resistivity depends on the intrinsic characteristics of the material, such as its composition and structure.

2. Apply the 2nd Ohm's Law: Students should be able to apply the 2nd Ohm's Law to calculate the electrical resistance of a conductor, given its resistivity and the dimensions of the conductor. They should understand that resistance is inversely proportional to the cross-sectional area of the conductor and directly proportional to its length.

3. Solve practical problems of resistivity and the 2nd Ohm's Law: Students should be able to solve practical problems involving the resistivity of a material and the application of the 2nd Ohm's Law. This includes calculating the resistance of a wire with known length and diameter, and determining the length of a wire given its resistance and diameter.

Secondary Objectives:

• Develop critical thinking and problem-solving skills: Through solving practical problems, students should develop their critical thinking and problem-solving skills by applying the concepts of resistivity and the 2nd Ohm's Law in different contexts.

• Promote active learning: The lesson plan is designed to promote active learning, encouraging students to actively participate in discussions and practical activities.

Introduction (10 - 15 minutes)

1. Review of previous concepts: The teacher should start the lesson by reviewing the concepts of electric current, resistance, and the 1st Ohm's Law. This review can be done through targeted questions to the students, encouraging their participation and checking the retention of these fundamental concepts.

2. Problem-based situations: Next, the teacher should present two problem-based situations involving resistivity and the application of the 2nd Ohm's Law. For example:

   • "Imagine you have two wires made of the same material, but one is twice as long as the other. Which wire has the higher resistance and why?"
   • "Suppose you have a wire with a resistance of 10 ohms. If you increase the diameter of the wire, does the resistance increase or decrease?"

3. Contextualization: Next, the teacher should contextualize the importance of the topic, explaining that resistivity is a fundamental property of the materials used in electrical wires and cables. Knowledge of resistivity allows designing efficient and safe electrical systems. Additionally, the application of the 2nd Ohm's Law is essential to understand how electrical resistance affects the flow of current in a circuit.

4. Introduction to the topic: To spark students' interest, the teacher can share curiosities or applications of the topic. For example:

   • "Did you know that the resistivity of copper is about 1/60 of the resistivity of iron? This is one of the reasons why copper is widely used in electrical wires."
   • "The 2nd Ohm's Law is used in many everyday applications. For example, when connecting a speaker to an amplifier, the speaker's resistance must be compatible with the amplifier's power, otherwise, the speaker may burn."

With this Introduction, students should be prepared for the Development of the lesson, with a clear understanding of the relevance and application of the concepts to be addressed.

Development (20 - 25 minutes)

1. Modeling Activity (10 - 15 minutes)

   • Preparation: The teacher should organize students into groups of three or four. Each group will receive a set of materials: wires of different materials (copper, iron, aluminum), ruler, tape measure, and a multimeter (or separate ammeter and voltmeter).

   • Activity: Each group should measure the length, diameter, and resistance of each wire. Students should record the measured values and the material of the wire.

   • Analysis and Discussion: After the measurement, the groups should calculate the resistivity of each wire using the 2nd Ohm's Law. Then, they should compare the obtained values with the provided resistivity values for each material. This will allow students to see the relationship between resistivity and the material's characteristics.

   • Conclusions: The groups should discuss together the conclusions reached. The teacher should guide the discussion, highlighting the main observations and reinforcing the concepts of resistivity and the 2nd Ohm's Law.

2. Practical Activity (10 - 15 minutes)

   • Preparation: The teacher should provide students with a series of practical problems involving resistivity and the 2nd Ohm's Law. The problems should vary in difficulty to meet the needs of different levels of student skills.

   • Activity: Students, still in groups, should work together to solve the problems. They should use the formulas of the 2nd Ohm's Law and the resistivity equation to calculate the answers.

   • Problem Solving: The teacher should circulate around the room, offering guidance and clarifying doubts as necessary. The goal is for students to apply the learned concepts to solve real problems.

   • Presentation of Solutions: After the set time, each group should present the solution to at least one of the problems. The teacher should facilitate a classroom discussion, allowing students to share their problem-solving strategies and learn from each other.

These activities allow students to explore the concepts of resistivity and the 2nd Ohm's Law in a practical and interactive way. By working in groups, students also have the opportunity to develop collaboration and communication skills.

Feedback (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes):

   • The teacher should gather all students in a large group and ask each group to share their solutions or conclusions from the previous activities.
   • Each group will have a maximum of 3 minutes to present, which will encourage clarity and conciseness in their presentations.
   • The teacher should encourage the exchange of ideas among groups, allowing them to ask each other questions and comment on their peers' presentations.
   • This group discussion will allow students to see a variety of approaches to problem-solving and reinforce the concepts of resistivity and the 2nd Ohm's Law.

2. Teacher's Verification (3 - 5 minutes):

   • After the groups' presentations, the teacher should provide a general review of the concepts and solutions presented, highlighting key points and correcting any misunderstandings.
   • The teacher may also ask additional questions to verify students' understanding and clarify any remaining doubts.
   • This teacher's verification is crucial to ensure that the learning objectives of the lesson were achieved and that all students understood the main concepts.

3. Individual Reflection (2 - 3 minutes):

   • Finally, the teacher should ask students to reflect individually on what they learned in the lesson.
   • The teacher can ask guiding questions, such as: "What was the most important concept you learned today?" and "What questions have not been answered yet?"
   • Students should have a minute to think about their answers, and then the teacher can ask some students to share their reflections with the rest of the class.
   • This individual reflection step allows students to consolidate their learning and identify any areas that they still do not fully understand.

This Feedback is a crucial part of the lesson, as it allows the teacher to assess the effectiveness of their instruction, provides students with the opportunity to clarify any remaining doubts, and helps reinforce and consolidate what was learned.

Conclusion (5 - 7 minutes)

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

   • The teacher should start the Conclusion by summarizing the main points covered during the lesson. This includes defining resistivity, the 2nd Ohm's Law and how to calculate it, and the relationship between resistivity, length, and cross-sectional area of a conductor.
   • It is important for the teacher to reiterate these concepts clearly and concisely, so that students can easily review them later.

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

   • Next, the teacher should explain how the lesson connected theory to practice. This can be done by highlighting how the modeling activity and the solving of practical problems allowed students to apply the theoretical concepts of resistivity and the 2nd Ohm's Law in a tangible and realistic way.
   • The teacher can recall some of the problem-based situations discussed during the lesson and how they were solved using the learned concepts.

3. Extra Materials (1 minute):

   • The teacher should then suggest some extra materials for students who wish to deepen their understanding of the topic. This may include books, articles, online videos, interactive simulations, among others.
   • For example, the teacher may recommend a video demonstrating the application of the 2nd Ohm's Law in a real electrical circuit, or an interactive website that allows students to explore how the resistivity of different materials affects electrical resistance.

4. Relevance of the Topic (1 - 2 minutes):

   • Finally, the teacher should emphasize the importance of the topic for everyday life. They should explain that resistivity is a fundamental property of the materials used in electrical wires and cables, and that the application of the 2nd Ohm's Law is essential to understand how electrical resistance affects the flow of current in a circuit.
   • The teacher can cite practical examples, such as the importance of resistivity in the efficiency and safety of electrical systems, and how the 2nd Ohm's Law is used in many everyday applications, such as when connecting a speaker to an amplifier.

With the Conclusion of the lesson, students should have a clear and comprehensive understanding of the topic, be aware of its relevance, and have the necessary resources to continue learning about the subject.