Objectives (5 - 10 minutes)

1. Understand the concept of microorganisms and their importance in food production: Students should be able to identify what microorganisms are and understand how they interact with the environment, playing an essential role in food production.

2. Recognize different types of microorganisms and their role in food production: Students should be able to identify the most common types of microorganisms used in food production, such as bacteria and yeasts, and understand how they act during the production process.

3. Apply the acquired knowledge in a practical activity: Students should apply the acquired knowledge through observation and participation in a practical activity, in which they will have the opportunity to produce a simple food using microorganisms.

Introduction (10 - 15 minutes)

1. Recalling previous concepts: The teacher starts the lesson by reminding students about what living beings are and their basic characteristics, emphasizing that humans, plants, and animals are not the only living beings on the planet. He may ask questions like 'Who remembers what living beings are?' or 'What are the characteristics of living beings that we remember?' to engage students in the discussion.

2. Problem situations: The teacher proposes two problem situations to arouse students' interest:

   • 'Have you ever wondered why bread rises when we add yeast to it?'
   • 'And why does yogurt turn sour after some time outside the refrigerator?'

3. Contextualization: The teacher explains that all the food we consume goes through a production process, and many of them depend on the action of small living beings, called microorganisms, to become what they are. He can give examples, such as bread that rises with the help of yeasts, yogurt that turns sour due to the action of bacteria, and cheese that is produced from the action of fungi.

4. Capturing students' attention: To capture students' attention, the teacher can share some curiosities about microorganisms and food production:

   • 'Did you know that there are more bacteria in our mouth than people in the world?'
   • 'And that without the action of bacteria, we wouldn't have foods like bread, cheese, and yogurt?'

5. Introduction to the topic: The teacher introduces the topic of the lesson, explaining that they will learn more about microorganisms and how they are important in food production. He can show images of different types of microorganisms and explain that there are good and bad microorganisms, and that the good ones are essential for our lives, including in food production. He may also mention that at the end of the lesson, they will have the opportunity to produce a simple food using microorganisms.

Development (15 - 20 minutes)

1. Activity: Making Yogurt

   • The teacher will divide the class into groups of up to five students. Each group will be provided with a small amount of milk and natural yogurt (without preservatives).
   • The teacher will explain that yogurt is produced through a process called fermentation, in which the bacteria present in the yogurt 'eat' the sugar in the milk and produce lactic acid. This lactic acid is what makes the yogurt sour.
   • The teacher will instruct the students to pour the yogurt into the milk and stir well. Then, they should cover the container with a clean cloth and leave it in a warm, dark place. This simulates the ideal conditions for the bacteria to develop.
   • During the activity interval, the teacher can provide students with more information about the fermentation process and the action of bacteria, encouraging them to ask questions and express their curiosities.
   • After approximately 15 minutes, the students will check the result. They will notice that the milk has thickened and turned sour, indicating that the bacteria have done their job and the fermentation process has occurred. They will have thus produced their own yogurt!

2. Activity: Yeast Growth in Bread

   • The teacher will divide the class into groups of up to five students. Each group will be provided with a small amount of flour, water, and baker's yeast.
   • The teacher will explain that baker's yeast is composed of yeasts, a type of fungus. When the yeast is added to the bread dough, the yeasts 'eat' the sugar in the flour and produce carbon dioxide gas. This carbon dioxide gas is what makes the bread rise.
   • The teacher will instruct the students to mix the flour, water, and yeast, forming a dough. Then, they should let the dough rest for a while, covered with a clean cloth. This simulates the ideal conditions for the yeasts to develop.
   • During the activity interval, the teacher can provide students with more information about the fermentation process and the action of yeasts, encouraging them to ask questions and express their curiosities.
   • After approximately 15 minutes, the students will check the result. They will notice that the dough has risen, indicating that the yeasts have done their job and the fermentation process has occurred. They will have thus produced their own bread!

3. Final Discussion

   • After the activities, the teacher should gather all students and start a discussion about the experiences they had. Students will have the opportunity to share their observations, discuss what they learned, and ask questions.
   • The teacher should reinforce the main concepts learned, explaining again the role of microorganisms in food production and the importance of the fermentation process.
   • To conclude the development, the teacher may propose a brief reflection, asking students what they thought of the activities and what they learned from them. This will allow the teacher to assess students' understanding of the subject and the effectiveness of the practical activities.

Return (10 - 15 minutes)

1. Group Discussion: The teacher will promote a group discussion with all students, where each team will have the opportunity to share their experiences, observations, and conclusions. He can ask questions like 'What did you notice in the milk after a few hours? And in the bread dough?' or 'How do you think bacteria and yeasts 'eat' the sugar in the milk and flour?'. This discussion will allow students to learn from each other and reinforce the concepts learned.

2. Connection with Theory: The teacher will make the connection between the practical activities and the theory presented in the introduction, explaining that what happened in the milk and bread dough was an example of the fermentation process, where bacteria and yeasts 'eat' the sugar in foods and produce substances that modify the taste, texture, and smell of these foods.

3. Individual Reflection: The teacher will propose that students reflect for a minute on what they learned in the lesson. He can ask two simple questions to guide students' reflection:

   • 'What was the most interesting thing you learned today about microorganisms and food production?'
   • 'How can you use what you learned today in your daily life?'

4. Teacher's Feedback: The teacher will provide feedback on the students' answers, highlighting the points he considered most relevant and making positive comments to reinforce learning. For example, he can say, 'I was happy to see that all of you were able to observe the fermentation process in action, and that you understood the role of microorganisms in food production' or 'I liked seeing how you engaged in the activities and asked interesting questions. This shows that you are really interested in the subject'.

5. Lesson Closure: To conclude the lesson, the teacher may suggest that students try making yogurt and bread at home, with the help of their parents or guardians. He can also provide reference materials, such as simple recipes and information about the fermentation process, so that students can continue learning and exploring the subject at home.

The return is a crucial part of the lesson, as it allows the teacher to assess students' understanding of the subject and the effectiveness of his teaching strategies. Additionally, it promotes reflection and critical thinking, essential skills for continuous and autonomous learning.

Conclusion (5 - 10 minutes)

1. Lesson Summary: The teacher will summarize the main points covered during the lesson, recalling the concepts of microorganisms, their importance in food production, and the fermentation process. He may recap the practical activities carried out, emphasizing the observations made by students and the conclusions drawn. The teacher may also take the opportunity to correct any misunderstandings or misconceptions that may have arisen during the discussion.

2. Connection between Theory and Practice: The teacher will highlight how the lesson managed to connect theory and practice. He may mention how the practical activities of making yogurt and bread helped illustrate the fermentation process and the action of microorganisms in a concrete and tangible way. He may also emphasize how the theory presented at the beginning of the lesson allowed students to better understand what they were doing during the activities.

3. Extra Materials: The teacher will suggest extra materials for students who wish to deepen their knowledge on the subject. This may include children's science books that talk about microorganisms and fermentation, educational videos available on the internet, or even simple recipes to continue exploring the world of fermentation at home. For example, he may recommend the book 'The World of Microorganisms' by Ruth Rocha, which is suitable for this age group and explores the topic in a playful and fun way.

4. Importance of the Subject: To conclude, the teacher will emphasize the importance of the subject for students' daily lives. He may explain that knowledge about microorganisms and fermentation is not only useful in food production, but also in many other aspects of life, such as food preservation, medicine production, and organic waste recycling. Additionally, he may emphasize that understanding how microorganisms work can help students stay healthy, as many diseases are caused by bacteria and other microorganisms.

The conclusion is an important part of the lesson plan, as it allows the teacher to consolidate what was learned, reinforce the connection between theory and practice, and highlight the relevance of the subject to students' lives. Furthermore, by suggesting extra materials, the teacher encourages continuous and autonomous learning, and shows students that science can be fun and interesting.