Contextualization

Theoretical Introduction

Chemical transformations, also known as chemical reactions, are processes that transform one or more substances, called reactants, into other substances - the products of that reaction. This transformation occurs through the breaking of the chemical bonds of the reactants, followed by the formation of new bonds to generate the products.

The types of chemical reactions are very varied, but all involve a change in the structure of molecules. These changes are governed by the laws of thermodynamics, which describe how energy is transferred during a reaction. Broadly speaking, we can divide reactions into exothermic, which release energy, and endothermic, which consume energy.

With a simple look, we can identify some evidence of a chemical transformation, such as a change in color, the formation of a gas (often observed by the formation of bubbles), and the formation of a precipitate, a solid substance that forms in a solution during a chemical reaction.

Contextualization

Chemical transformations are fundamental to the existence of life as we know it. They are present in all biological processes, such as cellular respiration, photosynthesis, and food digestion. Moreover, they are essential in various industries, such as chemistry, pharmaceuticals, food, among others, and many times, the final product we consume is the result of several consecutive chemical reactions.

Understanding chemical transformations helps us comprehend the processes that occur around us and even in our bodies. The relevance of knowing chemical reactions goes beyond the classroom, as it is present in everyday tasks - such as preparing food and using cleaning products, which are based on chemical reactions.

Practical Activity: Cooking with Chemistry

Objective:

Demonstrate the presence of chemical reactions in the kitchen, understand how these reactions occur, and see how they alter the properties of food. At the same time, integrate knowledge of Science and Mathematics through the development of recipes, proportional calculations, and measurements.

Project Description:

For this project, each group of 3 to 5 students will be transformed into a scientific kitchen team. The task will be to choose a recipe that involves ingredients with noticeable chemical reactions (for example, cake, bread, boiled egg, etc).

Students should:

1. Research the recipe and understand which chemical reactions are involved in the process.
2. Calculate the necessary proportions of the ingredients for the number of people in the team (or for a specific quantity of the final product if they want an extra challenge).
3. Prepare the recipe, documenting all steps of the process with photos and/or videos.
4. Discuss and explain the observed chemical transformations.

The total duration of the project should be at least 12 hours per student, including research time, preparation, recipe execution, and report writing.

Necessary Materials:

The necessary materials will depend on the chosen recipe, but all groups will need:

• Access to a kitchen with basic cooking utensils
• Ingredients from the chosen recipe
• Device for taking photos and/or recording videos
• Computer with internet access for research

Step by Step:

1. Choose a recipe: The team should choose a recipe that they are interested in and that incorporates chemical reactions, particularly those that can be directly observed (for example, yeast in action in a cake or bread).

2. Research: With the chosen recipe, the team should research the chemical reactions involved, understand why they occur, and how they change the properties of the ingredients.

3. Planning: Students should plan the execution of the recipe, including the necessary calculations for ingredient proportions.

4. Execution: Prepare the recipe as planned, documenting each step with photos and/or videos.

5. Analysis: Compare the before and after of the ingredients and discuss the chemical reactions that occurred, identifying visible evidence of these transformations.

6. Report writing: Write a report, including the research done, project planning, recipe execution, analysis of the results, and conclusions.

Project Deliverables:

At the end of the project, each group must deliver:

1. Written report: The report should contain the following topics:

• Introduction: Contextualization of the chosen recipe and the chemical reactions involved. Importance and application of these reactions in real life.
• Development: Details of the research conducted, calculations for ingredient proportions, recipe preparation steps with documentation by photos and/or videos, analysis of the observed chemical transformations correlating with the theory studied.
• Conclusions: Learning obtained, challenges encountered and overcome, surprises during the process, and connections made with the theory studied.
• Bibliography: Research sources used to understand the chemical reactions, proportions, etc.

2. Live presentation: Each group will make a live presentation to the class, explaining the process, showing photos/videos, and discussing their results and learnings.

Remember, this project is intended to be challenging, but also fun and engaging, so experiment, explore, and let your scientific curiosity and gastronomic creativity combine.