Contextualization

Coulomb's Law describes the electrostatic force between two charged particles. This law was established by the French physicist Charles-Augustin de Coulomb in 1785 and has since been one of the fundamental laws of physics.

Coulomb's Law can be expressed as: F = k * |q1*q2|/r^2. In this formula, F is the force of interaction between the two charges, q1 and q2 are the charges of the two particles, r is the distance between the particles and k is a constant called the Coulomb constant.

Coulomb's Law is the basis for understanding electrostatic phenomena and for describing the forces that govern the behavior of particles in the atomic and subatomic universe. It is a fascinating subject of paramount importance to physics.

In our daily lives, Coulomb's Law is present in countless situations. The static electricity we feel when rubbing a balloon on our hair, the functioning of our electronic devices, such as cell phones and computers, and even the simple act of turning on a light bulb are examples of phenomena that involve the electrostatic forces described by Coulomb's Law.

Coulomb's Law also plays a crucial role in many areas of modern technology. For example, particle accelerators and electron microscopes, vital tools in much scientific research, work based on the electrostatic forces described by this law.

We suggest the following resources for further study:

• Book "Physics for Scientists and Engineers" by Paul A. Tipler & Gene Mosca.
• Brasil Escola website about Coulomb's Law.
• Canal Ciência em Ação video about Coulomb's Law.

Practical Activity: Building an Electroscope

Project Objective

The objective of this project is for students to build an electroscope, one of the oldest instruments used in the study of electrostatics. The electroscope allows for the visualization of electrostatic charges and the understanding of concepts related to Coulomb's Law.

Detailed Project Description

Students should work in groups of 3 to 5 people. The project will last approximately two weeks, with each student dedicating 2 hours per day to the project activities, resulting in more than 12 hours of work per student.

The key concepts that students will need to understand and apply are:

1. Coulomb's Law
2. Electrostatic Forces
3. Nature of electric charges
4. Neutralization and electrostatic induction

This project will involve the disciplines of Physics and Arts, as students will build the electroscope with accessible materials.

Required Materials

1. Glass bottle with metal or plastic nozzle
2. Copper wire
3. Gold or aluminum leaves
4. Balloon
5. Wool, hair or paper towel

Step by Step

1. Take the copper wire and make a hook at the end.
2. Hang two gold or aluminum leaves on the hook.
3. Carefully insert the wire into the glass bottle, making sure that the leaves do not touch the sides of the bottle.
4. Rub the balloon on the hair, wool or paper towel to create a static charge.
5. Bring the charged balloon close to the nozzle of the bottle. Observe the behavior of the gold leaves.

During the project, students should record their observations, difficulties and results.

Project Deliverables

At the end of the project, students must submit a written report explaining the process of building the electroscope and the physical concepts involved. The report should be divided into four parts: Introduction, Development, Conclusions and Bibliography used.

1. Introduction: Students should explain what Coulomb's Law is, its importance and how it applies to our daily lives. In addition, they should describe what an electroscope is and the objective of the project, including the construction of the instrument.

2. Development: Students should detail each step of the process, explaining the reason for each step. They should apply the theoretical concepts of Coulomb's Law and electrostatic forces in explaining the operation of the electroscope, showing the relationship between theory and practice.

3. Conclusions: Students should share their findings, learnings and difficulties encountered throughout the project. They can also suggest other possible practical applications of Coulomb's Law.

4. Bibliography: Students should cite all sources of information used during the project, such as books, websites and videos.

The groups should present the constructed electroscope to the class, explaining its operation and their learnings during the construction and use of the apparatus. In addition, students should be prepared to answer questions from classmates and the teacher about the project.