Contextualization

Introduction to the Magnetic Field

The magnetic field is a vector physical quantity associated with the magnetic action that acts on particles of electric charges in motion. This quantity arises from the movement of electric charges, such as that produced by an electric current. The magnetic field at a specific point is determined by two factors: the value of the current and the geometry of the source that produces it.

When we have a circular conducting coil traversed by an electric current, it generates a magnetic field that can be mathematically described in an elegant way. The direction and sense of this field are determined by the Right-Hand Rule.

Contextualization of the Coil in the Magnetic Field

The circular coil is one of the simplest models for studying magnetic fields, but also one of the most powerful. The analysis of magnetic fields generated by coils is fundamental for understanding concepts present in everyday technologies, such as electric power generators, electric motors, and transformers.

Understanding the magnetic fields generated by a coil can also be explored in the understanding of concepts of magnetic resonance, a technology widely used in the healthcare field for mapping internal structures of the human body.

Practical Activity

Title: "Construction and Analysis of a Magnetic Field Generator - The Coil"

Project Objective

This project aims to deepen students' understanding of the magnetic field generated by a coil. Students should develop a coil, estimate and calculate the magnetic field generated by it, compare their results with theoretical values, and discuss possible sources of error. In addition, they should analyze the variation of the magnetic field as a function of changing variables such as the number of turns of the coil and the current flowing through it.

Project Description

Groups of 3 to 5 students will develop a circular coil, powered by a direct current source, which will be used to generate a magnetic field. The challenge is to calculate the magnetic field based on the coil's parameters and compare the theoretical result with the practical result, obtained through a teslameter (magnetic field meter), if available.

Required Materials

For the completion of this project, the following materials will be necessary:

1. Flexible copper conductor wire.
2. Compass or teslameter (if available).
3. Direct current power supply.
4. Multimeter.
5. Ruler or caliper for diameter measurement.

Step by Step

Coil Construction:

1. Wind the copper wire, forming a coil of approximately 10cm in diameter. Be careful not to make it too tight or too loose.
2. Note the number of turns the coil has.
3. Connect the wire ends to the direct current power supply.

Magnetic Field Measurement:

4. Adjust the electric current passing through the coil using the power supply. Note the value.
5. If available, use the teslameter to measure the magnetic field generated by the coil at its center. If there is no teslameter available, place a compass in the center of the coil: the variation in its behavior will indicate the presence of the magnetic field.
6. Repeat steps 4 to 5 for different values of electric current.

Results Analysis:

7. Using the studied theory, calculate what the value of the magnetic field should be for each condition.
8. Compare the theoretical values with the values obtained in practice. Discuss possible sources of error and how they can affect the result.

Project Delivery

At the end of the project, students must submit a report containing:

1. Introduction: Presentation of the theme (magnetic field generated by a coil), its relevance, real-world applications, and the project's objective.
2. Development: Presentation of the involved theory (how we theoretically calculate the magnetic field generated by a coil), details of the practical activity performed (steps, materials used, methodology), presentation and discussion of the results obtained (measured and calculated values, comparison between them, possible sources of errors, etc).
3. Conclusion: Recap of the main points of the project and the main learnings, conclusions drawn about the project.
4. Bibliography: Indication of the sources that supported the work, such as books, web pages, videos, etc.

It is expected that students learn to calculate the magnetic field generated by a coil and to solve problems that require this calculation. In addition, the project promotes socio-emotional skills such as time management, communication, problem-solving, creative thinking, and proactivity.