Lesson Plan | Traditional Methodology | Electricity: Electric Charge

Objectives

Duration: (10 - 15 minutes)

The purpose of this stage is to provide an overview of what will be addressed during the lesson, establishing a clear foundation for understanding the concept of electric charge. This will help students focus on the main points and understand the importance of each topic to be discussed. By the end of this section, students will have a clear idea of what is expected for them to learn and how it will apply in subsequent explanations.

Main Objectives

1. Understand the concept of electric charge.

2. Understand that only negative charge is transferred between bodies.

3. Calculate the charge of a body based on the electric charge of an electron.

Introduction

Duration: (10 - 15 minutes)

The purpose of this stage is to provide an overview of what will be addressed during the lesson, establishing a clear foundation for understanding the concept of electric charge. This will help students focus on the main points and understand the importance of each topic to be discussed. By the end of this section, students will have a clear idea of what is expected for them to learn and how it will apply in subsequent explanations.

Context

Start the lesson by explaining that electricity is a fundamental part of our modern world. From the operation of our electronic devices, such as smartphones and computers, to the lighting of our homes, electricity is present in almost every aspect of our lives. To understand electricity, it is essential to comprehend the concept of electric charge, which is the foundation of all electrical phenomena.

Curiosities

Did you know that one of the first discoveries about electricity was made by the ancient Greeks? They noticed that by rubbing amber with animal skin, the amber attracted small pieces of straw. This phenomenon was one of the first steps toward understanding static electricity. Additionally, the word 'electricity' comes from the Greek 'elektron', which means amber.

Development

Duration: (45 - 55 minutes)

The purpose of this stage is to deepen students' understanding of the concept of electric charge, its properties, and how charge transfer occurs in practice. By the end of this section, students will be able to define electric charge, understand its behavior in different situations, and perform basic charge calculations using the charge of an electron as a reference.

Covered Topics

1. Definition of Electric Charge: Electric charge is a fundamental property of subatomic particles that determines their electromagnetic interactions. There are two types of electric charges: positive and negative. Particles with opposite charges attract each other, while particles with the same charge repel each other. 2. Unit of Electric Charge: The unit of measure for electric charge in the International System (SI) is the Coulomb (C). The charge of an electron is approximately -1.6 x 10^-19 C. 3. Principle of Conservation of Electric Charge: In any isolated system, the total amount of electric charge remains constant. This means that electric charge cannot be created or destroyed, only transferred from one body to another. 4. Transfer of Electric Charge: Explain that in charging processes by friction, contact, and induction, only electrons (negative charges) are transferred from one material to another. Protons (positive charges) remain fixed in the nuclei of atoms. 5. Practical Examples of Electrification: Provide examples such as the electrification of a comb by rubbing it on hair or the electrification of a balloon by rubbing it on a wool shirt. These examples help visualize the transfer of electrons in practice. 6. Calculating the Charge of a Body: Demonstrate how to calculate the total charge of a body by multiplying the number of excess or deficit electrons by the charge of an electron. For example, if a body has an excess of 5 x 10^13 electrons, its total charge is (5 x 10^13) x (-1.6 x 10^-19 C).

Classroom Questions

1. What is the electric charge of a body with a deficit of 3 x 10^14 electrons? 2. Explain what happens in terms of charge transfer when a comb is rubbed against a piece of wool. 3. Calculate the total charge of a body that has an excess of 2 x 10^15 electrons.

Questions Discussion

Duration: (25 - 30 minutes)

The purpose of this stage is to review and consolidate students' understanding of the concepts discussed in the lesson. By discussing the answers to the questions, students have the opportunity to clarify doubts, correct possible errors, and deepen their understanding of electric charge and its principles. This feedback moment allows for more active and participatory learning, promoting student engagement and ensuring that everyone is keeping up with the content.

Discussion

• Discussion of Question 1: The electric charge of a body with a deficit of 3 x 10^14 electrons can be calculated by multiplying the number of electrons by the value of the charge of an electron. Therefore, the total charge is (3 x 10^14) x (1.6 x 10^-19 C) = 4.8 x 10^-5 C. Note that the sign is positive because there is a deficit of electrons, indicating a positive charge.

• Discussion of Question 2: When a comb is rubbed against a piece of wool, there is a transfer of electrons from the wool to the comb. This occurs due to the difference in the electronic affinities of the materials involved. The comb, by gaining electrons, becomes negatively charged, while the wool, by losing electrons, becomes positively charged.

• Discussion of Question 3: To calculate the total charge of a body that has an excess of 2 x 10^15 electrons, we multiply the number of electrons by the charge of an electron. Thus, the total charge is (2 x 10^15) x (-1.6 x 10^-19 C) = -3.2 x 10^-4 C. The negative sign indicates that the body is negatively charged.

Student Engagement

1. What is the importance of the principle of conservation of electric charge in the electrification of materials? 2. How would you explain the difference between electrification by friction, contact, and induction? 3. Why are only electrons transferred between bodies during electrification? 4. If a body initially neutral loses 1 x 10^12 electrons, what will its new electric charge be? 5. Describe a daily situation in which you can observe electrification by contact.

Conclusion

Duration: (10 - 15 minutes)

The purpose of this stage is to review and consolidate the knowledge acquired during the lesson. By summarizing the main points discussed and connecting theory with practice, students have the opportunity to review and reinforce their understanding, ensuring a complete and integrated comprehension of the topic of electric charge.

Summary

• Definition of electric charge as a fundamental property of subatomic particles.
• Existence of two types of electric charges: positive and negative.
• Unit of measure for electric charge in the International System (SI) is the Coulomb (C).
• Principle of conservation of electric charge.
• Transfer of electric charge occurs only with electrons (negative charges).
• Practical examples of electrification, such as rubbing a comb in hair or a balloon on a wool shirt.
• Calculation of the charge of a body based on the charge of an electron.

The lesson connected theory with practice by providing concrete examples of electrification, such as rubbing a comb in hair or a balloon on a wool shirt, and guiding students in solving practical problems of electric charge calculation. This helped illustrate how the abstract concepts of electric charge manifest in everyday life and are applicable in real situations.

Understanding electric charge is essential for the comprehension of many everyday phenomena, from the operation of electronic devices to natural phenomena such as lightning. Knowing that only electrons are transferred between bodies during electrification allows for a deeper understanding of how and why objects become electrified, which is fundamental to both science and technology.