Lesson plan of Electricity: Ohm's First Law

Objectives (5 - 7 minutes)

1. Understand the concept of Ohm's law, which describes the relationship between electric current, resistance, and voltage applied to an electric circuit.
2. Apply Ohm's law formula (V = R * I) to solve practical problems involving electric current, resistance, and voltage in a circuit.
3. Relate Ohm's law to everyday life by identifying practical examples of how the law applies to real-world situations.

Secondary objectives:

• Encourage active participation by students in the learning process, promoting discussion and group problem-solving.
• Develop critical-thinking and problem-solving skills in students by applying the theory of Ohm's law to practical situations.
• Foster interest in physics among students by demonstrating how its principles apply in the real world.

Introduction (10 - 15 minutes)

1. Review of previous knowledge: The teacher should begin the lesson by recalling important concepts covered previously, such as the definition of electric current, voltage, and resistance. Furthermore, the idea that electricity is an essential component in our lives and present in almost all activities we carry out should be reinforced.

2. Problem situations: The teacher should present two situations that pique the students' curiosity and make them question how Ohm's law applies. For example, one could ask why a light bulb glows brighter when a new battery is inserted, or why a shower gets hotter when we increase the power setting. These situations will help students understand the relevance of the topic and the importance of their studies.

3. Contextualization: The teacher should explain the importance of Ohm's law in various areas of everyday life. For instance, the law is fundamental to electrical engineering and is used in the design of circuits and troubleshooting electrical problems. In addition, the law is applied in various professions, such as electricians and engineers, who need to understand how current, voltage, and resistance operate in a circuit.

4. Introduction to the topic: To capture the students' attention and spark interest in the subject, the teacher could share some fun facts. For example, they could mention that Ohm's law was formulated by Georg Simon Ohm in 1827 and that the unit of electrical resistance, the ohm, was named in his honor. Another interesting fact is that Ohm's law is one of the most fundamental laws in physics and is used worldwide in a wide range of applications.

Development (20 - 25 minutes)

1. Activity "Unveiling Ohm's Law" (10 - 12 minutes):

   • Divide into groups: The teacher should divide the class into groups of up to 5 students. Each group will receive a set of materials that include a battery, conducting wires, a light bulb, and a current and voltage meter.
   • Task: Each group should assemble a simple circuit by connecting the battery to the light bulb and the current and voltage meter, according to the teacher's instructions. The aim is to observe how current, voltage, and resistance are interconnected.
   • Data recording: After assembling the circuit, the students should record the current and voltage meter readings. Next, they should replace the light bulb with one of a higher wattage and record the readings again. Finally, they should replace the light bulb with one of a lower wattage and repeat the process.
   • Group discussion: Following the observations, each group should discuss and record their conclusions. They should try to relate their observations to Ohm's law formula (V = R * I).

2. Activity "Applying Ohm's Law in Real Situations" (10 - 13 minutes):

   • Introduction to the scenario: The teacher should present the students with a series of everyday situations that involve electricity, such as the operation of a shower, a light bulb, a fan, among others.
   • Group analysis: Each group should choose one of these situations and, using Ohm's law, try to explain what happens in the circuit. They should identify the current, resistance, and voltage in the circuit and explain how an increase or decrease in one of these variables would affect the functioning of the appliance.
   • Presentation of conclusions: Each group should present their conclusions to the class, explaining how Ohm's law applies to the situation they chose. The teacher should mediate the discussion, clarifying doubts and reinforcing the concepts.

3. Activity "Ohm's Law Quiz" (5 - 10 minutes):

   • Preparation: The teacher should prepare a quiz with multiple-choice questions and problems involving Ohm's law. The questions should be varied, addressing different aspects of the law and applying it to a variety of situations.
   • Quiz implementation: Each group should answer the quiz together. The teacher should circulate around the room, clarifying doubts, and monitoring the groups' progress.
   • Correction and discussion: After the quiz has been completed, the teacher should correct it, discussing the correct answers and clarifying any doubts that may have arisen.

The lesson Development is the time when students will have the opportunity to apply in practice what they learned in the Introduction. The proposed activities are designed to promote collaboration and discussion among students, encouraging critical thinking and problem-solving. Moreover, the activities are contextualized, which will help students understand the relevance of the topic to their own lives.

Closure (8 - 10 minutes)

1. Sharing of Group Conclusions (3 - 4 minutes)

   • The teacher should ask each group to share their solutions and conclusions on the activities carried out. Each group will have up to 3 minutes to share, ensuring that all students have the opportunity to speak.
   • During the presentations, the teacher should encourage students to explain how they arrived at their conclusions, making references to Ohm's law and the formula V = R * I.
   • The teacher should ask questions to stimulate students' reflection, such as: "Why do you think the current increased when you changed the light bulb to one with lower resistance?" or "How do voltage and resistance affect the brightness of a light bulb?".

2. Connection to Theory (2 - 3 minutes)

   • After all the presentations, the teacher should provide a brief summary, connecting the groups' conclusions to the theory of Ohm's law.
   • The teacher should highlight the main ideas and concepts that emerged from the activities, reinforcing the relationship between current, voltage, and resistance, and how these quantities relate to each other according to Ohm's law.
   • The teacher can then review the formula V = R * I, explaining again what each quantity represents and how they are related.

3. Individual Reflection (2 - 3 minutes)

   • Finally, the teacher should ask the students to do an individual reflection on what they learned in the lesson.
   • The teacher should ask questions to guide students' reflection, such as: "What was the most important concept you learned today?" and "What questions are still unanswered?"
   • Students should have a minute to think about their answers. They can then share their reflections with the class, if they wish.

The Closure is a crucial part of the lesson, as it allows the teacher to assess students' progress and identify any gaps in understanding. Additionally, it gives students the opportunity to reflect on what they have learned and how they can apply this knowledge in future situations. By the end of the Closure, students should have a solid understanding of Ohm's law and how it applies in the real world.

Conclusion (5 - 7 minutes)

1. Content Summary (1 - 2 minutes)

   • The teacher should begin the Conclusion by recapping the main points discussed during the lesson. This includes the definition of Ohm's law, the relationship between electric current, resistance, and voltage, and the formula V = R * I.
   • The teacher should recall the activities carried out and the conclusions reached by the students, reinforcing how they illustrate and apply the theory of Ohm's law.

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

   • Next, the teacher should highlight how the lesson succeeded in establishing connections between the theory, practice, and applications of the subject.
   • The teacher should reinforce how the practical activities allowed students to apply the theory of Ohm's law in real-world contexts, and how group discussions and individual reflection helped solidify students' theoretical understanding.

3. Extra Materials (1 minute)

   • The teacher should suggest extra materials for students who wish to further their knowledge of Ohm's law. This could include explanatory videos, circuit simulation websites, physics books, among others.
   • For example, the teacher could suggest the following experiment for students to try at home: try to light a bulb using different combinations of batteries and copper wires, and observe how current, resistance, and voltage interrelate in this context.

4. Importance of the Subject in Everyday Life (1 - 2 minutes)

   • Finally, the teacher should emphasize the importance of Ohm's law in everyday life.
   • The teacher should explain that understanding this law is fundamental to grasping the operation of many electrical appliances we use daily, from light bulbs and showers to computers and cell phones.
   • Furthermore, the teacher can stress that Ohm's law is essential for professions involving electricity, such as electricians and engineers, and that, therefore, the knowledge acquired in the lesson may have practical and professional applications in students' futures.

The Conclusion is a crucial time to consolidate students' learning and to ensure that they have grasped the key concepts of the lesson. Additionally, by highlighting the topic's relevance to the real world, the teacher can help increase student engagement and motivation to learn more about the subject.