Objectives (5 - 10 minutes)

Main Objectives:

1. Understand the definition and role of resistors in an electrical circuit, especially in parallel.
2. Develop the ability to calculate the total resistance of a circuit with resistors in parallel.
3. Learn to apply Ohm's Law to calculate the current flowing through each resistor and the voltage across the entire circuit configuration.

Secondary Objectives:

1. Stimulate the ability to analyze and interpret electrical circuit diagrams.
2. Promote the practice of problem-solving involving electricity and resistance concepts.
3. Encourage active participation and discussion in the classroom, fostering a collaborative learning environment.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher starts the lesson by reviewing the concepts of resistors and Ohm's Law. It is important for students to have a good understanding of these concepts as they will form the basis for understanding the current topic. The teacher can do this through a brief theoretical review, followed by some practical examples to reinforce learning. (3 - 5 minutes)

2. Problem Situations: The teacher presents two problem situations to arouse students' interest and contextualize the importance of the topic to be studied.

   • Situation 1: 'Imagine you have a circuit with several light bulbs connected in parallel. If one of the light bulbs burns out, what will happen to the other light bulbs? And to the intensity of the electric current in the circuit?'

   • Situation 2: 'Now, imagine you have a circuit with two batteries in parallel. How would adding a second battery affect the intensity of the electric current in the circuit? And the voltage?' (5 - 7 minutes)

3. Contextualization: The teacher explains that understanding resistors in parallel is essential to comprehend the operation of many everyday electrical devices, such as light bulbs, electronic devices, and even cars. The teacher may also mention that this is an important topic for solving practical problems and for test and exam preparation. (2 - 3 minutes)

4. Introduction to the Topic: To capture students' attention, the teacher can introduce the topic of resistors in parallel with two curiosities or practical applications:

   • Curiosity 1: 'Did you know that most electronic devices we use in our daily lives, such as smartphones, tablets, and computers, use circuits with resistors in parallel? This is because resistors in parallel allow the electric current to be efficiently distributed among the circuit components.'

   • Curiosity 2: 'Have you ever wondered why, when a light bulb burns out in a circuit with several light bulbs connected in parallel, the other light bulbs remain lit? This happens because, in a circuit with resistors in parallel, the electric current is divided among the resistors, so that even if one resistor fails, the electric current continues to flow through the other resistors.' (3 - 5 minutes)

Development (20 - 25 minutes)

1. Activity 'Light Circuits' (10 - 12 minutes)

   • Necessary Materials: 2 small LED light bulbs, 2 AA batteries, conductor wires with alligator clips, 1 lamp holder, 1 switch, 2 10-ohm resistors.

   • Preparation: The teacher must preassemble the circuit by connecting the light bulbs in parallel, with one resistor in each of them. The batteries should be connected in series, providing the voltage to the circuit. The switch should be placed in series with the batteries.

   • Development: Students will be divided into groups of up to 5 people. Each group will receive an assembled circuit and must perform the following tasks:

     1. Measure the resistance of each light bulb and each resistor with a multimeter.
     2. Calculate the total resistance of the circuit (suggestion: record the resistances in a table and sum them).
     3. Calculate the current passing through each light bulb and the resistor (using Ohm's Law).
     4. Observe and record the brightness of the light bulbs when the switch is turned on and off.

   • Discussion: After the activity, the teacher should lead a discussion in the classroom, highlighting the concepts of resistors in parallel, total resistance, current, effects of resistance change, and voltage. Students should be encouraged to share their observations and conclusions.

2. Activity 'Calculating Total Resistance' (10 - 13 minutes)

   • Necessary Materials: Paper, pencil, and calculator.

   • Development: The teacher will present students with a hypothetical scenario of a circuit with resistors in parallel. The students, in their groups, will have to:

     1. Draw the circuit diagram, clearly indicating the resistors.
     2. Choose values for the resistors (e.g., 10 ohms, 20 ohms, 30 ohms).
     3. Calculate the total resistance of the circuit.
     4. Calculate the current passing through each resistor, assuming a voltage of 12 volts.
     5. Verify their answers by building the circuit with the actual resistors and measuring the current with an ammeter.

   • Discussion: The groups should present their results to the class. The teacher must ensure that all calculations are correct and explain any errors that may have occurred. This will help reinforce the concepts and practice of the students.

   These practical activities will allow students to experience and better understand the concepts of resistors in parallel, total resistance, current, and voltage. Additionally, they promote teamwork, discussion, and problem-solving skills, essential for active and collaborative learning.

Return (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes)

   • The teacher requests each group to share their solutions or conclusions from the activities carried out. Each group will have up to 3 minutes to present their observations, challenges encountered, and how they overcame them.
   • After all presentations, the teacher should summarize the main points addressed, highlighting the successes and correcting any possible misinterpretations.
   • The teacher can take this opportunity to reinforce the importance of collaboration and teamwork, emphasizing that these are fundamental skills for both physics and life.

2. Connection with Theory (3 - 5 minutes)

   • The teacher should then connect the practical activities carried out with the theoretical concepts presented in the Introduction of the lesson.
   • For example, it can be highlighted how the activities demonstrated the division of electric current in a circuit with resistors in parallel, the variation of total resistance, and the application of Ohm's Law.
   • The teacher should encourage students to make connections on their own, asking them, for example, how the addition of a resistor would affect the total resistance of the circuit or the current passing through each resistor.

3. Individual Reflection (2 - 3 minutes)

   • To conclude the lesson, the teacher should propose that students reflect individually on what they have learned.
   • The teacher can ask questions like: 'What was the most important concept you learned today?' and 'What questions have not been answered yet?'.
   • Students should write down their answers and, if they wish, share them with the class or hand them to the teacher.
   • This individual reflection helps students consolidate what they have learned and identify any gaps in their understanding, which can be addressed in future lessons.

4. Teacher Feedback (1 - 2 minutes)

   • Finally, the teacher can provide general feedback on the class's participation and performance during the lesson.
   • The teacher should praise the students' efforts, highlight strengths, and offer guidance for improvements.
   • This will help motivate students and keep them engaged in the learning process.

This final Return is crucial for students to consolidate what they have learned, make connections with theory, and prepare for the next lesson. Additionally, it provides the teacher with the opportunity to assess the class's progress and adjust the planning of future lessons, if necessary.

Conclusion (5 - 10 minutes)

1. Recap of Contents (2 - 3 minutes)

   • The teacher should start the Conclusion by briefly summarizing the main points covered in the lesson. This includes the definition of resistors, Ohm's Law, the total resistance of a circuit with resistors in parallel, and how to calculate the current flowing through each resistor and the voltage across the entire circuit.
   • It is important for the teacher to reinforce these concepts as they will serve as the basis for future lessons, which will address more advanced topics in electricity.

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

   • Next, the teacher should explain how the lesson connected theory to practice. This may include a discussion of the activities carried out and how they helped illustrate the theoretical concepts.
   • The teacher can, for example, mention how the 'Light Circuits' activity allowed students to see in practice how resistors in parallel affect the current and voltage in a circuit. Or how the 'Calculating Total Resistance' activity reinforced the application of Ohm's Law.

3. Supplementary Materials (1 - 2 minutes)

   • The teacher should then suggest additional study materials for students who wish to deepen their knowledge of resistors in parallel. This may include textbooks, physics websites, educational videos, and practical exercises.
   • For example, the teacher may suggest that students watch a video explaining resistors in parallel, read a chapter on the subject in a physics book, and try to solve additional practical problems.

4. Importance of the Topic (1 - 2 minutes)

   • To conclude the lesson, the teacher should emphasize the importance of resistors in parallel in the real world. This may include a discussion on how resistors in parallel are used in everyday electronic devices, such as light bulbs, electronic devices, and even cars.
   • The teacher may also mention that understanding resistors in parallel is essential for solving practical problems and for test and exam preparation.

5. Closure (1 minute)

   • The teacher thanks the students for their participation and effort during the lesson.
   • The teacher reminds students to review the concepts and practice calculations at home.
   • Finally, the teacher announces the topic of the next lesson and encourages students to prepare in advance by reading the recommended study material.

The Conclusion is an essential part of the lesson as it helps students consolidate what they have learned, make connections to the real world, and prepare for future lessons. Additionally, it provides students with the necessary resources to continue learning independently.