Objectives (5 - 7 minutes)

1. Understand the concept of buoyancy in hydrostatics, understanding that when a body is immersed in a fluid, it will be subject to a vertical force, from bottom to top, of the same intensity as the weight of the fluid displaced by the body.

2. Apply the buoyancy formula (E = ρgV) to solve practical problems. Students should be able to identify the quantities involved in the formula (fluid density, gravity acceleration and volume of displaced fluid) and relate them correctly.

3. Understand the Archimedes' Principle and its application in everyday life. Students should understand that a body submerged in a fluid is subject to a force from bottom to top, which is buoyancy, and that the variation in buoyancy is equal to the weight of the displaced fluid.

Secondary objectives:

• Stimulate students' critical thinking and problem-solving skills by providing practical examples and problem-solving situations that require the application of the concepts of buoyancy and Archimedes' Principle.

• Foster classroom discussion, promoting active student participation and the sharing of ideas and solutions.

• Develop the skill of research and autonomous study, encouraging students to seek complementary information on the lesson topic.

Introduction (10 - 15 minutes)

1. Review of related content: The teacher should start the lesson by briefly recalling the concepts of density, weight and lift force, which are fundamental to understanding buoyancy. It is important that students are familiar with these concepts so that they can understand the new topic that will be addressed.

2. Problem situations: The teacher can propose two problem situations to stimulate students' thinking:

   • Situation 1: "Imagine you have an object made of steel and another made of cork. If both are placed in a container of water, what will happen? Why does this happen?"

   • Situation 2: "Imagine you are in a swimming pool and decide to dive. Why do you float in the water and not sink completely?"

3. Contextualization: The teacher should highlight the importance of hydrostatics and buoyancy in our daily lives, mentioning practical applications such as the flotation of boats and ships, the operating principles of submarines and hot air balloons, and even the reason why we feel lighter when we are in water.

4. Introduction to the topic: The teacher should then introduce the topic of buoyancy, mentioning that this is a very important physical phenomenon that governs the behavior of objects immersed in fluids. To arouse students' interest, the teacher can share some curiosities, such as:

   • Curiosity 1: "Did you know that the principle of buoyancy was discovered by Archimedes, a Greek mathematician and physicist, while he was taking a bath? He realized that the water level in the bathtub rose when he got in, and this led him to formulate the famous Archimedes' Principle."

   • Curiosity 2: "Have you ever heard of the USS Iowa battleship? It is so large and heavy that if it were placed in a swimming pool, it would sink. However, when it is in the ocean, it floats. This is due to buoyancy, which is greater in the ocean's salt water than in the fresh water of a swimming pool."

The teacher can then move on to the next step, which is the theoretical explanation of the topic.

Development (20 - 25 minutes)

1. Theoretical explanation of buoyancy and Archimedes' Principle (10 - 12 minutes): The teacher should begin the theoretical explanation of buoyancy by reinforcing the concept of density and emphasizing that it is the ratio of the mass of a body to its volume. Then, the concept of buoyancy should be introduced, which is the vertical force that a fluid exerts on a body immersed in it, counterbalancing the weight of the body.

   • The teacher should then introduce the buoyancy formula (E = ρgV), explaining what each of the symbols represents: E is the buoyancy, ρ is the density of the fluid, g is the acceleration of gravity, and V is the volume of the fluid displaced by the immersed body.

   • The teacher should emphasize that, according to Archimedes' Principle, a body immersed in a fluid is subject to a force from bottom to top, which is buoyancy, and that the variation in buoyancy is equal to the weight of the displaced fluid.

   • The teacher should explain that if the weight of the body is less than the buoyancy, the body floats; if the weight is greater, the body sinks; and if the weight is equal to the buoyancy, the body is in equilibrium, floating partially immersed.

2. Practical demonstration of buoyancy and discussion of examples (5 - 7 minutes): The teacher should perform a simple practical demonstration to illustrate the concept of buoyancy.

   • The teacher can use a container of water and some objects of different materials and weights, such as a Styrofoam ball, a steel ball, a coin, etc.

   • The teacher should ask students to predict what will happen when the objects are placed in the water and then perform the demonstration, explaining what is happening based on the concepts of buoyancy and Archimedes' Principle.

   • The teacher should encourage student participation by asking questions and promoting discussion of the examples to ensure that they have understood the concepts presented.

3. Problem solving (5 - 6 minutes): The teacher should propose some application problems of buoyancy for the students to solve, individually or in small groups.

   • The problems should involve applying the buoyancy formula and interpreting Archimedes' Principle.

   • The teacher should circulate around the room, assisting students who encounter difficulties and clarifying any doubts that may arise.

At the end of this step, students should have understood the concept of buoyancy, be able to apply the buoyancy formula and interpret Archimedes' Principle, and have developed the skill of solving problems related to buoyancy.

Feedback (10 - 15 minutes)

1. Discussion and Reflection (5 - 7 minutes): The teacher should promote a classroom discussion, asking students to share their answers and solutions to the proposed problems. This is an opportunity for students to reflect on what they have learned and for the teacher to check if the learning objectives have been achieved.

   • The teacher should start by asking students to share the solutions they found for the problems. He should then question students about how they applied the buoyancy formula to solve the problems and how they interpreted Archimedes' Principle.

   • The teacher should encourage participation from all students by asking open-ended questions and encouraging students to explain their reasoning.

   • The teacher should also correct any misconceptions that arise during the discussion, ensuring that students have correctly understood the concepts.

2. Connection to Theory (2 - 3 minutes): The teacher should then connect the discussion to the theory presented, reinforcing the key concepts and explaining again how they were applied to solve the problems.

   • The teacher can, for example, ask students how the buoyancy formula was used to determine the buoyancy force in each of the problems, and how the interpretation of Archimedes' Principle helped to understand what would happen to the objects immersed in the fluids.

3. Final Reflection (3 - 5 minutes): To conclude the lesson, the teacher should propose that students reflect individually on what they have learned.

   • The teacher can ask questions such as: "What was the most important concept you learned today?" and "What questions are still unanswered?".

   • The teacher should give students a minute to think about their answers. Then, he can ask some students to share their reflections with the class.

   • The teacher should pay attention to students' reflections, as they can provide valuable insights into what students have learned and what aspects of the content still need to be reinforced in future lessons.

At the end of this step, students should have had the opportunity to reflect on what they have learned, to share their reflections and doubts, and to connect theory with practice. The teacher, in turn, should have obtained feedback on the effectiveness of the lesson and on how he can improve the teaching of the topic in the future.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion of the lesson by briefly summarizing the main contents covered. He should recall the concepts of buoyancy, Archimedes' Principle, and how to apply the buoyancy formula to solve problems. The teacher can use a whiteboard or a slide presentation to visualize the concepts and formulas.

2. Theory-Practice Connection (1 - 2 minutes): Then, the teacher should highlight how the lesson connected theory and practice. He can mention that the theoretical explanation of buoyancy and the practical demonstration helped to solidify students' understanding of the subject. The teacher can also emphasize how problem-solving allowed students to apply theoretical concepts in a practical way and to better understand the subject.

3. Complementary Materials (1 minute): The teacher should then suggest complementary study materials for students. He can indicate books, websites, videos or applications that provide more in-depth explanations of buoyancy and Archimedes' Principle, or that offer more examples and problems for students to practice. The teacher can also suggest that students review their notes and solve the proposed problems again at home to reinforce what they have learned.

4. Importance of the Subject (1 - 2 minutes): Finally, the teacher should emphasize the importance of buoyancy and Archimedes' Principle for everyday life. He can mention again practical examples, such as the flotation of boats and ships, and the feeling of lightness we have when we are in water. The teacher can also emphasize that buoyancy is one of the fundamental principles governing the behavior of fluids, and that it is widely applied in various areas of science and engineering.

At the end of the Conclusion, students should have consolidated what they learned during the lesson, understood the connection between theory and practice, and be motivated to continue studying the topic. The teacher, in turn, should have reinforced the main points of the content, provided resources for additional study, and highlighted the relevance of the subject to students' lives.