Context

Ohm's first law is one of the fundamental concepts in physics, especially in the field of electricity. This law deals with the relationship between current, resistance, and potential difference (also known as voltage) in an electrical circuit. According to Ohm's first law, the current passing through a conductor between two points is directly proportional to the applied voltage and inversely proportional to the conductor's resistance. Mathematically, we can express this as: V = i.R, where V is the voltage, i is the current, and R is the resistance.

To better understand this law, we can make an analogy with a water pipe. Imagine the current as the amount of water passing through the pipe, the voltage as the pressure pushing the water, and the resistance as the diameter of the pipe. If we increase the pressure (voltage), more water (current) will pass through the pipe. However, if we decrease the diameter of the pipe (increase the resistance), less water will pass, even if the pressure is the same.

Ohm's first law has important practical applications in our daily lives. It is used to design electrical circuits in household appliances, cars, power systems, and many other devices that use electricity. It is also the basis for understanding other laws and principles of electricity, such as the Node Law and the Mesh Law. Without Ohm's first law, it would be almost impossible to understand and control the use of electricity.

Practical Activity

Activity Title: "Simulation of Electrical Circuits and Ohm's Law"

Project Objective:

The main objective is to understand Ohm's first law and its practical application in building electrical circuits, through collaborative and practical work in groups. By the end, students will be able to design, build, and analyze electrical circuits, using Ohm's first law as the main tool.

Detailed Project Description:

The groups, consisting of 3 to 5 students, must:

1. Design a simple electrical circuit that uses at least one power source, two resistors, and a switch. The design should be done on paper and should include the identification of components and the connections between them.
2. Build the designed electrical circuit. For this, students can use materials such as batteries, cables, small bulbs (like flashlight bulbs), resistors, switches, and a mounting board.
3. Measure the voltage, current, and resistance at different points in the circuit. Note that, to make these measurements, students will need a multimeter or a voltmeter and an ammeter.
4. Analyze the results of the measurements and discuss how they are related to Ohm's first law.
5. Modify the circuit - for example, by adding more resistors or changing its configuration - and repeat the measurements and analysis.

Required Materials:

• Sheets of paper and drawing pens for designing the project
• Batteries
• Cables
• Small bulbs (like flashlight bulbs)
• Resistors
• Switch
• Mounting board
• Multimeter (or voltmeter and ammeter)

Detailed Step-by-Step for Activity Execution:

1. Form groups of 3 to 5 students.
2. Each group should draw and plan a simple electrical circuit, identifying the components and showing how they are connected.
3. Based on the design, students should build the circuit using the provided materials.
4. Next, students should use the multimeter to measure the voltage, current, and resistance at different points in the circuit.
5. Students should analyze the results of the measurements and discuss how they correspond to Ohm's first law.
6. After that, students should modify the circuit (add more resistors, change the configuration, etc.) and repeat the measurements and analysis.

Project Deliverables:

• The drawing and description of the initial and modified design of the electrical circuit.
• A record of the voltage, current, and resistance measurements made in the circuit.
• A discussion on how the measurement results relate to Ohm's first law.

All these elements should be compiled into a written report, which should also include:

• Introduction: Contextualize Ohm's first law, its importance and application, as well as the objectives of the activity.
• Development: Describe in detail the circuit (initial and modified design), the measurements made, and the results obtained, analyzing these results in light of Ohm's first law.
• Conclusions: Discuss the skills learned, the challenges encountered and how they were overcome, as well as the relevance of the activity in understanding Ohm's first law.
• Bibliography: Indicate the sources of information consulted for the report preparation and activity execution.