Contextualization

Gas pressure is a fundamental concept in physics and chemistry that describes the force a gas exerts on the walls of its container. It is calculated by dividing the total force exerted by the gas by the area of the container's wall, usually expressed in units of Pascal (Pa).

The kinetic theory of gases provides an explanation for gas pressure. According to this theory, gases are composed of a large number of molecules that are constantly in random motion. When these molecules collide with the walls of the container, they exert a force on the walls, resulting in pressure.

The Ideal Gas Law is another important approach to understanding gas pressure. This law states that the pressure of a gas is directly proportional to its absolute temperature and the number of gas molecules and inversely proportional to the volume of the container. Therefore, if the volume of a container containing a gas is reduced, the gas pressure will increase, while if the temperature is reduced, the gas pressure will decrease.

Importance of Gas Pressure

Gas pressure plays a critical role in many aspects of everyday life and science. In power plants, the pressure of water vapor is used to spin turbines to generate electricity. In car or bicycle tires, gas pressure is the force that supports the weight of the vehicle. In hot air balloons, the low pressure of the hot air compared to the surrounding cold air makes the balloon rise.

In medicine, the pressure of gases such as oxygen and carbon dioxide in the blood is crucial for the healthy functioning of the human body. In high-altitude conditions or underwater, gas pressure can have a significant impact on the human body, leading to altitude sickness or decompression sickness, respectively.

Practical Activity

Activity Title: Gas Pressure Experiment

Project Objective

In this project, the main objective is to explore the concept of gas pressure through the experiment and connect the theory learned in the classroom with a practical experience. Students will enhance their understanding of gas laws and the relationship between pressure, volume, temperature, and the number of gas particles.

This project also aims to develop students' teamwork, time management, and communication skills as they will work in groups to conduct the experiment and prepare a report.

Detailed Project Description

Groups will conduct a series of experiments to investigate how gas pressure is affected by different variables. They will collect data, interpret it, and present it in a formal report.

Required Materials

1. 60 ml syringe (without needle)
2. Latex balloons of various colors
3. Ice cubes
4. Hot water
5. Thermometer
6. Scale

Step by Step

1. Inflate a balloon to a certain size (e.g., 10 cm in diameter) and measure its mass using the scale.
2. Place the balloon in the empty syringe, press the plunger to a certain volume (e.g., 20 ml), and record the difficulty in pressing.
3. Repeat the previous steps, but this time, add ice cubes to the balloon before placing it in the syringe.
4. Next, repeat the previous steps, but now add hot water to the balloon before placing it in the syringe.
5. Collect all data and observed results.

Project Deliverables

Students must prepare a formal project report to be submitted in digital format containing:

• Introduction: Should contextualize the topic of gas pressure, its relevance and real-world applications, as well as the objective of this project.

• Development: Should explain the theory behind the central theme of the project, which is gas pressure, explain the activity in detail, indicate the methodology used, and finally present and discuss the results obtained. They can use graphs to better illustrate their results.

• Conclusion: Should conclude the work by summarizing its main points, explaining the knowledge gained and the conclusions about the project, as well as the relationship between theory and practice.

• Bibliography: Should indicate the sources they relied on to work on the project, such as books, web pages, videos, etc.

Project Duration

It is expected that the project will last approximately 15 hours per student, including conducting the experiment, analyzing the data, and preparing the report.