Context

The average scalar speed is a physical quantity defined as the ratio between the total scalar displacement and the elapsed time. In everyday life, we use this measure when planning trips, organizing our transportation routine, and even when practicing physical exercises, such as running. A good understanding of this quantity will be essential for solving problems and questions in the discipline of Physics.

In mathematics, speed is represented by the ratio of displacement over time. But in physics, it is different: we consider not only how much displacement has been made, but also the direction of this displacement, which makes the concept even more interesting. Furthermore, understanding average speed is the first step to comprehend other physical concepts, such as acceleration.

In the modern world, speed has become an essential measure. Vehicles are designed to reach a certain average speed, delivery companies work with delivery times based on average speeds, and the industry, in general, uses this quantity to calculate the efficiency and performance of machinery and processes.

Average speed is also a crucial concept to understand current environmental issues. The speed at which natural resources are consumed, for example, can be an indicator of the environmental impact of certain human activities. Furthermore, the development of new technologies and productive processes is based on precise calculations of average speed.

To deepen the concepts of average scalar speed, we recommend the book 'Fundamentals of Physics' by Halliday and Resnick, available in the school library. In addition, the website 'Just Physics' has a section dedicated to the subject, with clear and detailed explanations. We also recommend the YouTube channel 'Science Every Day', which presents several videos on the topic in a very didactic and accessible way.

Practical Activity

Activity Title: Balloon Race

Project Objective:

Understand and apply the concept of average scalar speed through a fun and participatory experimental activity, enhancing teamwork.

Detailed Project Description:

Students, divided into groups of 3 to 5, will carry out a 'balloon race' in a flat area of the school. The idea behind this experiment is to measure the time it takes for the balloon to cover a fixed distance, thus allowing to calculate its average scalar speed. Students will document the process, make observations, and calculate the average scalar speed of their balloons.

Required Materials:

1. Balloons of different colors (one for each group).
2. Stopwatches or cell phones with stopwatch function.
3. Tape measure or large ruler.
4. Camera or cell phone to document the process.

Step by Step:

1. Choose a safe and appropriate location for the race.
2. Mark the starting line and the finish line of the course with a fixed distance (We suggest 10 meters to facilitate calculations).
3. Each group will inflate the balloon and release it at the starting line, one group at a time.
4. Using the stopwatch, students will measure the time it takes for the balloon to cross the finish line from the moment it was released.
5. Each group will make three attempts to ensure the accuracy of the results.
6. Students should record the times of the three attempts and then calculate the average of these times.
7. With the fixed distance of the course and the average time obtained, students will be able to calculate the average scalar speed of the balloon using the formula: speed = distance/time.
8. Students should document the entire process, from preparation to the race and calculations, through photos, videos, or written records.

At the end of the project, students should compile all their findings, calculations, and reflections in a report containing:

1. Introduction: Contextualization of the average scalar speed theme, relevance and real-world application, and the project's objective.
2. Development: Detailed discussion on the concept of average scalar speed, detailed description of the activity - from preparation, execution, and calculations, to the methodology employed, presentation of the results obtained, and discussion based on these results.
3. Conclusion: Return to the main points, reflection on the learnings obtained, and conclusions about the project.
4. References: List of research sources and bibliographic references that were used to understand the concept and develop the project.

This activity, besides promoting a practical understanding of the average scalar speed concept, also encourages teamwork collaboration and problem-solving.