Objectives (5-10 minutes)

1. Understand the concept of heat flux and its importance in calorimetry.
2. Learn to calculate heat flux using the formula Q = k * A * ΔT / d, where Q is heat flux, k is thermal conductivity, A is heat transfer area, ΔT is temperature difference, and d is the distance between the two surfaces.
3. Apply the heat flux formula in practical and contextualized situations.

Secondary objectives:

• Develop logical and mathematical reasoning skills in problem-solving.
• Stimulate curiosity and interest in Physics through practical and relevant applications.
• Promote understanding of the relevance of Physics in everyday life and in various fields of knowledge.

In this step, the teacher will clearly present the Learning Objectives of the lesson, explaining the importance of heat flux in calorimetry and how heat flux is calculated. It is also important for the teacher to highlight the Secondary Objectives, emphasizing the importance of Developing logical and mathematical reasoning skills, as well as curiosity and interest in Physics.

Introduction (10-15 minutes)

• Review of previous concepts: The teacher should begin the lesson by briefly reviewing the calorimetry concepts already studied, such as the law of conservation of energy, the difference between heat and temperature, and the units of heat measurement (calorie and joule). This review aims to prepare students for the new content to be covered, ensuring that everyone is on the same page.

• Problem situations: Next, the teacher should propose two problem situations that involve heat flux. For example, "How does heat move from a hot pan to the water inside it?" or "Why do we feel the floor cold when we step on it barefoot, even if the air temperature is warm?". These situations aim to arouse students' curiosity and motivate them to understand the concept of heat flux.

• Contextualization: The teacher should then contextualize the importance of heat flux, explaining how it is present in various everyday situations and in different fields of knowledge. For example, heat flux is essential for understanding how thermal insulation works in our homes, how heat propagates in the human body, and even how heat transfer works in industrial processes.

• Introduction to the topic: Finally, the teacher should introduce the concept of heat flux, explaining that it refers to the transfer of heat from a region of higher temperature to a region of lower temperature. The teacher can do this through an analogy, comparing heat flux to the flow of water from a higher region to a lower region. This Introduction aims to prepare students for the content that will be covered in class and arouse their interest in the topic.

Development (20-25 minutes)

• Heat Flux Theory and its Formula (10-12 minutes): The teacher should introduce the theory of heat flux and explain the formula Q = k * A * ΔT / d, step by step.

  1. First, the teacher should explain that heat flux (Q) is directly proportional to the temperature difference (ΔT) between the two surfaces and the heat transfer area (A). This means that the greater the temperature difference and the heat transfer area, the greater the heat flux.
  2. Next, the teacher should explain that heat flux is inversely proportional to the distance (d) between the two surfaces. This means that the greater the distance between the two surfaces, the lower the heat flux.
  3. The teacher should then introduce the concept of thermal conductivity (k), which is a property of the material that determines how easily heat passes through it. The teacher should explain that thermal conductivity is a constant for each material and that the higher the thermal conductivity, the greater the heat flux.
  4. Finally, the teacher should explain that the formula Q = k * A * ΔT / d combines all these factors and allows us to calculate the heat flux in a specific situation.

• Demonstration of Heat Flux Calculation (5-7 minutes): The teacher should then demonstrate how to calculate heat flux using the formula Q = k * A * ΔT / d.

  1. The teacher should present a problem situation, for example, "What is the heat flux through a brick wall that is 2 meters wide, 3 meters high, and 20 centimeters thick, if the temperature difference between the two sides of the wall is 10°C, and the thermal conductivity of the brick is 0.6 W / (m·K)?".
  2. Next, the teacher should guide the students in calculating the heat flux, step by step. The teacher should start by substituting the values into the formula, and then performing the mathematical operations to obtain the final result. During the process, the teacher should explain each step and answer students' questions.

• Heat Flux Calculation Practice (5-6 minutes): Finally, the teacher should propose a few more heat flux calculation exercises so that students can practice what they have learned. The teacher should closely monitor the students' exercise solving, clarifying doubts, and providing feedback.

In this step, the teacher should ensure that the explanation of the heat flux theory and formula is clear and understandable, using examples and analogies whenever possible. The teacher should also encourage active student participation by asking questions, requesting examples of everyday situations involving heat flux, and encouraging discussion. In addition, the teacher should ensure that students have the opportunity to practice calculating heat flux so that they can apply what they have learned independently.

Feedback (10-15 minutes)

• Group Discussion (5-7 minutes): The teacher should begin this step by proposing a group discussion on what was learned. Students should be encouraged to share their conclusions and reflections on the concept of heat flux and the formula Q = k * A * ΔT / d. The teacher should guide the discussion by asking questions that encourage students to think more deeply about the concept and its practical applications. For example, the teacher might ask: "How do you think the heat flux formula can be applied in everyday situations?" Or, "Can you think of any situation where the heat flux formula could be useful?" During the discussion, the teacher should encourage all students to participate, valuing their contributions and promoting an environment of respect and cooperation.

• Connection to Theory (2-3 minutes): After the group discussion, the teacher should return to the theoretical concepts presented and make the connection with the students' reflections. The teacher should emphasize how the theory of heat flux and the formula Q = k * A * ΔT / d allow us to understand and predict heat transfer in various everyday situations and in various fields of knowledge. The teacher should also highlight the importance of calculating heat flux for engineering, architecture, medicine, climatology, and other areas.

• Individual Reflection (3-5 minutes): Finally, the teacher should propose that students do an individual reflection on what they learned in class. The teacher should ask questions that encourage students to think critically about the lesson content and how it relates to the world around them. For example, the teacher might ask: "What was the most important concept you learned today?" or "How do you plan to apply what you learned today in your daily life?" Students should have a minute to think about their answers, and then anyone who wants to can share their reflections with the class. The teacher should value all responses, as the goal of this activity is to encourage students to reflect on what they have learned and to make connections between theory and practice.

In this step, the teacher should ensure that all students have the opportunity to actively participate in the discussion and reflections, respecting the pace and individual characteristics of each student. The teacher should also summarize the main ideas discussed, reinforcing the most important concepts and clarifying possible doubts. Finally, the teacher should end the class in a clear and concise manner, reinforcing the main points covered and the importance of heat flux and heat flux calculation in calorimetry.