Contextualization

Hydrostatics is a branch of physics that is dedicated to studying fluids at rest. Due to its everyday application and its relevance in understanding many phenomena that occur around us, its approach is of utmost importance in the teaching of Physics. The key concepts of hydrostatics are: pressure, density, buoyancy, and Pascal's principle.

The pressure of a fluid is the force exerted by it perpendicularly to the unit of area. In a fluid at rest, the pressure is the same at all points of the same depth, which is known as Stevin's Law. The density of a fluid is the mass per unit volume, being a quantity that characterizes each substance.

Pascal's principle states that a change in pressure caused in a fluid at rest is transmitted integrally to all points of that fluid and to the walls of the container. And finally, buoyancy is the upward vertical force that a fluid exerts on a submerged or floating body, resulting from Archimedes' principle.

Real World Applications

Have you ever stopped to think about the number of everyday situations where hydrostatics is present? When taking a shower, the water that reaches the shower is an example of the action of pressure in fluids. Submarines use the concepts of density and buoyancy to submerge and emerge. And a car's brakes use Pascal's principle to function.

Furthermore, many environmental problems, such as the contamination of groundwater by toxic waste, use hydrostatic concepts to be understood and solved. Therefore, the study of hydrostatics has great technical, scientific, and social relevance.

Practical Activity: The Challenge of Fluids!

Project Objective

The objective of this project is to build a miniature submarine using simple materials and demonstrate the concepts of pressure, density, buoyancy, and Pascal's principle.

Detailed Project Description

Students, in groups of 3 to 5 members, should build a miniature submarine that can submerge and emerge in a container with water. The group should explore and explain the hydrostatic fundamentals that allow the submarine's movement, integrating theory with practice. The project should be documented in all its stages and culminate in the delivery of a detailed report.

Required Materials

• Small plastic bottles (beverage type)
• Barbecue sticks
• Balloons
• Adhesive tape
• Rubber band
• Weight (can be clay, small stone, or any material that can be added to adjust the submarine's buoyancy)
• A large container to fill with water (can be a basin or an aquarium)

Detailed Step-by-Step

1. Submarine Construction: Students will build the submarine using the plastic bottles as the main body, the barbecue sticks as the axis, and the balloons as the flotation system. They will use adhesive tape to fix all components and the rubber band to adjust the balloons' opening. Weights will be added to ensure that the submarine can submerge.

2. Experimentation and Adjustments: Next, students will test the submarine in the container with water, observing and documenting how the variation of pressure and buoyancy influences the submarine's buoyancy. If necessary, they will make adjustments to the design (adding more weight, for example).

3. Application of Concepts: Students will explore and explain the hydrostatic concepts involved in the submarine's operation, such as: pressure, density, buoyancy, and Pascal's Principle.

4. Final Report: Finally, students will write a project report, explaining the objective, the methodology applied, the results obtained, as well as the conclusions about the hydrostatic concepts involved.

Project Deliverables

Students must deliver the miniature submarine and the detailed project report. The report should contain the following sections:

1. Introduction: should contextualize the theme, the relevance and application of hydrostatic concepts in the real world, as well as the objective of this project.

2. Development: should explain the theory behind the key hydrostatic concepts, describe in detail the activity (submarine construction), the methodology used, and finally present and discuss the results obtained.

3. Conclusion: should summarize the main points of the project, explaining the learnings obtained and the conclusions drawn about the hydrostatic concepts.

4. Bibliography: should indicate the sources they relied on to work on the project, such as books, web pages, videos, etc.

The total project duration is expected to be at least twelve hours per participating student.