Contextualization

When we talk about physical forces, certainly one of the first that comes to mind is gravity. This is indeed the most easily observable force in our daily lives. However, there are other forces acting all the time, even if we do not see them - or feel them - as directly as gravity. One of these examples is the electric force. In an increasingly connected world dependent on electrical and electronic systems, understanding this force becomes crucial.

The electric force is described by Coulomb's law, which establishes that two charged bodies attract or repel each other with a force proportional to the product of their charges and inversely proportional to the square of the distance between them. This force, like all others, can do work, which is a fundamental concept in physics.

The work done by a force is related to its ability to cause changes in energy in a system, whether potential energy, kinetic energy, among others. In the specific case of the electric force, when it does work, it changes the electric potential energy of a system, which can be used to define the electric charge at a point or to calculate velocities, depending on the situation.

Importance

The electric force is the basis of our modern electricity and electronics. From simply turning on a light to complex satellite communication, the electric force is in action. Furthermore, chemical reactions, which are the basis of life and many industrial processes, are also phenomena governed by the electric force. Understanding the work of this force is the first step to comprehend the theory that governs many of the phenomena around us.

Studies on the electric force and its work also have a significant impact on research and development of sustainable energy sources, such as photovoltaic cells used in solar panels, for example. Such technology uses the electric force to convert solar energy into electrical energy.

Practical Activity

Activity Title: The Work of Electric Force in Action

Project Objective:

The objective of this activity is to offer students a practical experience regarding the work of the electric force. Students will build a mini wind energy project, where a moving charge will cause work and, therefore, energy.

Detailed Project Description:

Students, divided into groups of 3 to 5 members, will build a small homemade wind energy generator. Without the need for complex tools or expensive materials, students will be able to observe the electric force in action, experience the work done by it when moving a charge, and learn about related Physics concepts.

Required Materials:

• Small DC motor (3 to 12 volts)
• LED
• Connection wires
• Wine cork
• Popsicle sticks (or equivalent plastic rods)
• Adhesive tape
• Scissors
• Magnet

Step-by-Step Guide for the Activity:

1. Use the wine cork as the base for the mini wind tunnel. Attach the popsicle sticks (or equivalent rods) to it forming a kind of cross. This will be the wind turbine of the generator.
2. Fix the motor on the top of the cork, so that the motor shaft is in contact with the wind turbine. When the sticks rotate, they will make the motor rotate as well.
3. Connect the wires to the motor and the LED, ensuring that the current can flow. Pay attention when making the connections, be careful not to cause shorts.
4. Place the magnet near the motor. The idea is that the force of the magnetic field helps generate an electric current in the motor.
5. Now, make the turbine spin. It can be done with the help of a fan or simply by blowing. If everything is correct, the LED will light up - proving that the work of the electric force can be converted into energy.

Project Deliverables:

Each group must deliver a detailed report on the project, explaining how the wind energy generator was assembled, what difficulties were encountered, how the generator works, and how the electric force is involved in the process.

The report should be divided into:

1. Introduction: Students should contextualize the work of the electric force, its relevance in everyday life, industry, and science. Additionally, they should indicate the objective of this project and the relevance of its completion.
2. Development: In this section, students should report step by step the construction of the generator, which materials were used, and what each of them represents in the simulation. They should also explain, based on the theory studied, how the generator works and how the electric force does work. Students should discuss the results obtained and whether they are as expected.
3. Conclusion: Students should review the work done, the conclusions drawn, and the learnings provided by this project. They can also suggest improvements to the project or additional tests that could be carried out.
4. Bibliography: Students should indicate the sources consulted for the project.

Remember that in addition to the theoretical and practical understanding of the electric force, this project also aims to develop socio-emotional skills such as time management, communication, problem-solving, creativity, among others.