Contextualization

Levers are simple mechanical devices that have been used since ancient times. You may not realize it, but we use them daily in various activities. A lever consists of a rigid bar that rotates around a fixed point, known as the fulcrum. It facilitates the performance of work because it requires less force to move a load than if you tried to lift it directly.

There are three classes of levers, depending on the position of the applied force (effort), the load, and the fulcrum. First-class levers have the fulcrum between the load and the effort, like a seesaw. Second-class levers have the load between the fulcrum and the effort, like a wheelbarrow. And third-class levers where the effort is between the fulcrum and the load, like a fishing rod.

The lever operates according to the principle of conservation of energy. The total energy in the system (considered isolated) remains constant. The force applied on one side produces an equal and opposite force on the other, allowing a smaller object to be moved with less force.

Levers are fundamental in our daily lives and are present in many mechanisms, from pliers to cranes. They allow us to perform tasks that would be very difficult, or even impossible, without their help. For example, try to imagine moving a large heavy object, like a stone, without the help of a lever!

The concept of the lever is also widely used in engineering, from building construction and bridges to the creation of tools and machines. In the human body, bones and muscles act together as levers to allow movement.

To delve deeper into the theme 'Levers' and understand how they work, we recommend the following resources:

1. Book 'Physics for High School', by Ramalho, Nicolau, and Toledo.
2. The Khan Academy Physics website (Link Here)
3. YouTube videos on the subject, such as the channel 'Physics and Related Topics'.
4. The 'Brazil School' website that presents didactic content (Link Here)

Practical Activity: Project 'Leveraging Knowledge'

Project Objective:

This project aims to apply and expand students' knowledge about the concept of levers, studying their practical applications and demonstrating their principles empirically.

Detailed Description:

Students should research and study the different classes of levers, discussing their practical applications and their relevance in society. In addition, the group will build models of the three classes of levers using simple materials, in order to visually demonstrate each type and explain the operating principle.

Required Materials:

• Small wooden sticks or rods;
• String or rope;
• Kitchen scale or another way to measure weight;
• Objects of various weights to serve as loads;
• Calculator (optional, but useful).

Step-by-Step for Activity Execution:

1. Theoretical Study: Students should study the three classes of levers through the indicated resources. They should understand how each class works, the differences between them, and some examples of everyday applications.

2. Building the Models: Each group member should build a model of a specific class of lever using the provided materials. To build the model, identify the location to serve as the fulcrum, to apply the effort, and to position the load.

3. Experimentation: After building the models, you will conduct experiments by varying the location of the effort and the fulcrum and recording the variations in the forces required to lift different loads. Record your data for further analysis.

4. Data Analysis: Here, students will analyze the collected data, establishing relationships between the position of the effort, fulcrum, and the load. They must clearly identify the operating principles of each class of lever.

5. Preparation of the Report: Finally, students must prepare a detailed report on the work, following the guidelines below.

Project Delivery:

The following must be delivered:

1. Lever Models: The models built for the three classes of levers.

2. Written Report: A report will be prepared by the students, containing the following topics:

• Introduction: Should provide a brief summary of levers, their importance, and practical applications.

• Development: Should contain a detailed description of the project, including the construction of the models, the experiments conducted, and the analysis of the data obtained.

• Conclusion: Here, students should put the learnings acquired during the project execution and how the theory applies to the real world.

• Bibliography: References to the research materials used for the project.

The deliveries must clearly demonstrate the students' understanding of the theme 'Levers' and its practical application. Remember, the goal is not only to understand how levers work but also to know how to apply this knowledge to solve everyday problems.