Introduction

Ohm's First Law, named after Georg Simon Ohm, is one of the first topics introduced when studying electricity in physics. This law postulates that the current passing through a conductor between two points is directly proportional to the applied electrical voltage. This relationship is often expressed in the form of the equation V=IR where V is the electrical voltage, I is the current, and R is the resistance.

In this concept, it is also important to understand what electrical resistance is. Resistance is the opposition that a device or material offers to the passage of electric current. It depends on intrinsic characteristics of the material such as resistivity and length, and is directly related to the dissipation of energy in the form of heat (Joule effect).

Electric current, in turn, is the flow of electrons through a conductor when there is an applied potential difference. It is measured in Amperes and can occur in two ways: direct current (DC), when electrons always flow in the same direction, and alternating current (AC), when the direction of electron flow constantly changes.

Context

Ohm's first law reveals the relationship between current, voltage, and resistance and is a foundation for the study and analysis of electrical circuits, which are key components in many technologies we use in our daily lives, such as smartphones, computers, electric cars, etc.

Understanding and applying Ohm's Law is also crucial in many professional fields, such as electrical engineering, telecommunications, scientific research, and even careers in the energy industry. Furthermore, Ohm's law underlies the principles of electrical safety, which are essential to prevent accidents and incidents related to electricity.

Practical Activity

Activity Title: "Building and Analyzing a Basic Electrical Circuit"

Project Objective

In this activity, the objective is to build a simple electrical circuit and apply Ohm's First Law to understand the relationship between current, voltage, and resistance. The project will provide student groups with the opportunity to conduct a practical experiment, discuss the physics concepts involved, work as a team, and present a final report.

Detailed Project Description

Students will be divided into groups of 3 to 5 members. Each group will be responsible for building a simple electrical circuit, which includes a voltage source (battery), a resistor, and wires to connect these components.

Students will measure the voltage at different points in the circuit and the intensity of the electric current. Then, they will calculate the resistance of the resistor using Ohm's first law and compare the obtained value with the nominal resistance of the resistor (which is indicated on it). They will also understand the concept of energy dissipation in the form of heat.

Students will reflect and discuss the results obtained, the applicability and limitations of Ohm's law, and the importance of electrical resistance in practice.

Students should write and present a detailed report of the work done, which should include results, calculations, conclusions, and discussions.

Required Materials

1. 1.5V Batteries (2 units)
2. 10 ohms Resistor (1 unit)
3. Digital Multimeter
4. Connection wires
5. Protoboard (optional)

Step-by-Step Guide for the Activity

1. Organize into groups of 3 to 5 students.
2. Acquire all the necessary materials for the activity. Remember to use new batteries for more accurate results.
3. Assemble the circuit by placing the battery and resistor in series. The connections should be secure to avoid losses.
4. Using the multimeter, measure the battery voltage and record the value.
5. Set the multimeter to measure electric current and insert it in series in the circuit. Record the current value.
6. Applying Ohm's Law, calculate the resistance of the resistor and compare the obtained value with the nominal resistance of the resistor.
7. Discuss with the group members the results obtained. Does the resistor resistance correspond to the nominal value? If not, why might this have happened? What does electrical resistance mean in practice? What relationships between voltage, current, and resistance were observed?
8. Write a detailed report, including the project objective, the methodology used (with a circuit diagram), the measurements taken, the calculations made, the results obtained, and the discussion around the results.
9. Review and finalize the report as a team, ensuring that all members agree on the content.

Project Deliverables and Report Development

The practical project should culminate in the delivery of a written report, which should include sections on Introduction, Development, Conclusions, and Bibliography used.

The Introduction should contextualize the theme of Ohm's First Law, its relevance, and how the practical activity helped understand this law. The Development should present the methodology used in the project execution, the detailed step-by-step guide, the measurements taken, the calculations made, and the results obtained. In the Conclusions section, students should summarize the main points, explain the learnings obtained, and draw conclusions about the project. Finally, in the Bibliography, students should indicate the sources they relied on to carry out the practical activity and write the report.

In this way, at the end of the project, students will have acquired technical skills related to practical experimentation and the use of Ohm's First Law, as well as socio-emotional skills such as teamwork, time management, communication, and problem-solving.