Objectives (5 - 7 minutes)

1. Understanding the Concept of Atom: Students should be able to understand the concept of an atom as the smallest unit of a substance that still retains the properties of that substance. They should understand that atoms are composed of a central nucleus, which contains protons and neutrons, and a cloud of electrons orbiting the nucleus.

2. Identification of Atom Parts: Students should be able to identify the different parts of the atom, including the proton, neutron, and electron. They should understand the characteristics and charges of each of these subatomic particles.

3. Understanding the Importance of Studying the Atom: Students should comprehend the importance of studying the atom for the understanding of various natural phenomena and for the development of modern technologies. They should be able to discuss how atoms combine to form molecules and how changes in the atom's structure can result in different substances and properties.

Secondary Objectives:

• Development of Scientific Skills: Teaching the concept of the atom should be used as an opportunity to develop students' scientific skills, including observation, asking questions, collecting, and analyzing data.

• Promotion of Critical Thinking: Students should be encouraged to question, discuss, and evaluate the information presented, thus promoting the development of critical thinking.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should start the lesson by reviewing the concepts of matter, subatomic particles, and molecules that were discussed in previous classes. This step is crucial to prepare the ground for the introduction of the atom concept.

2. Problem-Solving Situations: Next, the teacher should present two problem-solving situations to arouse students' interest and demonstrate the importance of studying the atom:

   • Situation 1: 'Did you know that a single drop of water contains billions and billions of hydrogen and oxygen atoms? How do these atoms organize to form the water we drink?'

   • Situation 2: 'Have you heard about nuclear energy? Did you know that it is produced from reactions that occur in the nucleus of atoms? This shows how the study of the atom is fundamental for energy generation, one of the main challenges of humanity today.'

3. Contextualization of the Importance of the Atom: The teacher should then contextualize the importance of studying the atom, mentioning how understanding its structure and behavior has contributed to advances in various areas such as medicine, materials technology, energy, and the food industry. For example:

   • Example 1: 'Understanding the structure of DNA, which is formed by atoms, has allowed significant advances in medicine, such as the discovery of cures for genetic diseases and the possibility of early diagnoses.'

   • Example 2: 'Semiconductors, which are used in almost all electronic devices, such as computers and cell phones, are made of materials whose properties are controlled by the atom's structure.'

4. Introduction of the Topic: Finally, the teacher should introduce the topic of the lesson, which is the atom. To capture students' attention, he can share some curiosities, such as:

   • Curiosity 1: 'Did you know that the atom is 99.999999999% empty space? This means that if we could compress all the empty space in the atoms that make up the human race, we would fit in the space of a sugar cube!'

   • Curiosity 2: 'Another interesting curiosity is that the word 'atom' comes from Greek and means 'indivisible.' The ancient Greeks believed that the atom was the smallest particle of matter and could not be divided. However, today we know that atoms are composed of even smaller particles, protons, neutrons, and electrons.'

Development (20 - 25 minutes)

1. Activity 1: Building an Atom Model (10 - 15 minutes):

   • Materials Needed: Balloons, beans or buttons, markers, glue, cardboard paper (or any other material that can be used to create a poster).

   • Activity Description: Students, divided into groups, will be tasked with creating an atom model. The balloon will represent the electron cloud, the beans or buttons will represent the protons and neutrons, and the markers will be used to mark the charges of the protons (positive), neutrons (neutral), and electrons (negative). The cardboard paper will be used to create a poster that explains the parts of the atom and their charges. The idea is for students to visualize and manipulate the parts of the atom to facilitate understanding of its functioning.

   • Step by Step:

     1. Instruct students to inflate the balloon and hold the opening with their fingers to prevent air from escaping.

     2. Ask them to place the beans or buttons inside the balloon.

     3. Then, ask them to draw the symbols of the subatomic particles and their charges on the beans or buttons.

     4. Finally, ask them to create an explanatory poster, where they will draw the atom model and write the function of each part.

2. Activity 2: The Atom Game (10 - 15 minutes):

   • Materials Needed: Atom cards (cards with the representation of atoms of different chemical elements, indicating the number of protons, neutrons, and electrons), 'combination' cards (cards with the representation of atoms that can combine to form a molecule), and 'reaction' cards (cards with the representation of atoms that react with other atoms to form new substances).

   • Activity Description: Students, still in groups, will participate in a card game where they will have to combine and react different atoms to form molecules and new substances. Each group will receive a set of cards and will have to follow the rules of the game to make the combinations and reactions. The goal is for students to understand how atoms combine and react to form different substances.

   • Step by Step:

     1. Instruct students to form a circle with the atom cards facing down.

     2. Explain the rules of the game: each time a student plays, they must try to combine an atom from their hand with an atom from the circle to form a molecule. If they succeed, they continue playing. If not, it's the next student's turn.

     3. Then, explain that from time to time, you will play a 'reaction' card. If a student plays an atom that reacts with the atom from the 'reaction' card, both are removed from the game, and the other atoms of the molecule remain.

     4. The game continues until all cards have been played. The group that has formed the most molecules is the winner.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes): The teacher should gather all students and promote a group discussion about the solutions or conclusions found by each team. Each group will have up to 2 minutes to share their atom model and the insights they gained during the activity. The teacher should encourage the participation of all students, asking questions and requesting them to explain the reasoning behind their solutions.

2. Connection with Theory (2 - 3 minutes): After the group discussion, the teacher should make the connection between the practical activities and the theory presented at the beginning of the lesson. He should highlight how the activities helped solidify the theoretical concepts, allowing students to visualize and manipulate the parts of the atom. The teacher should also reinforce the importance of studying the atom, recalling the examples presented in the Introduction and how the knowledge about the atom's structure and behavior has contributed to the development of various technologies and the understanding of natural phenomena.

3. Individual Reflection (2 - 3 minutes): The teacher should then propose that students reflect individually on what they learned in the lesson. He should ask questions like:

   1. 'What was the most important concept you learned today?'
   2. 'What questions have not been answered yet?'

   Students should have a minute to think about their answers. After that, they can share their reflections with the class if they wish. The teacher should encourage the participation of all but respect the decision of those who prefer not to share.

4. Teacher's Feedback (1 minute): Finally, the teacher should provide general feedback on the class's participation and performance during the lesson. He should praise the students' effort and dedication, highlight strengths, and offer suggestions for improvement for the next lessons. The goal is to encourage students to continue striving and improving their study and learning skills.

Conclusion (5 - 7 minutes)

1. Recap of Content (2 - 3 minutes): The teacher should start the Conclusion by recalling the main points covered during the lesson. He should recap the definition of an atom as the smallest unit of a substance that still retains the properties of that substance, the parts of the atom (proton, neutron, and electron), their characteristics, and charges. The teacher should also reinforce the importance of studying the atom for the understanding of various natural phenomena and the development of modern technologies.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes): The teacher should then highlight how the lesson managed to connect the theory, practice, and applications of the study of the atom. He can mention how the activity of building the atom model allowed students to visualize and manipulate the parts of the atom, helping to solidify the theoretical concepts. Additionally, the teacher should reinforce the practical applications of the study of the atom discussed during the lesson.

3. Extra Materials (1 minute): The teacher can suggest some extra materials for students who wish to deepen their knowledge about the atom. These materials may include videos, websites, books, and interactive online activities. Some examples of resources could be the video 'The Atom: Crash Course Chemistry #3' from the Crash Course channel on YouTube, the website 'Chem4Kids' that offers an interactive introduction to chemistry, and the book 'A Short History of Nearly Everything' by Bill Bryson, which explores the history of science, including the study of the atom.

4. Relevance of the Topic (1 - 2 minutes): Finally, the teacher should reinforce the relevance of the lesson's topic to students' daily lives. He can mention how knowledge about the atom is important for understanding the composition of the materials around us, from the water we drink to the electronic devices we use. Additionally, the teacher can highlight how the study of the atom is fundamental for the advancement of science and technology, contributing to problem-solving and the development of new technologies.