This week, the main focus in physics is studying sound waves. Students have learned that sound is produced by the vibration of objects. However, not all sounds produced by vibrations can be heard by us because the human ear can only hear sounds with frequencies ranging from 20 hertz to 20,000 hertz. Sound waves produced by vibrations that are too slow or too fast are called infrasound and ultrasound, which are undetectable by the human ear. In class, students were very interested in their own hearing thresholds. They downloaded apps for hearing threshold tests online and conducted experiments to verify the scientific validity of the hearing threshold range given in the physics book. This critical thinking approach was highly praised among the students.

Students also learned about the harm caused by noise pollution. As one of the four major environmental pollutions in today's society, noise pollution prompted students to share their own life experiences. Through their studies, they discovered ways to mitigate the harm caused by noise pollution from three aspects: the source, transmission pathways, and receivers. For example, installing double-glazed windows at home helps to isolate noise from the transmission pathways. This interconnected approach between theory and practice is indeed the best way to learn physics.

When discussing the measurement of the speed of sound propagation, students showed exceptional creativity in thinking of various methods to measure the speed of sound. For example, they proposed using a starting gun and a stopwatch during a 100-metre race to measure the speed of sound propagation. They also identified potential issues that could arise during the experiment, such as the distance being too short. If the distance is too short, the time it takes for the sound wave to propagate may be shorter than our reaction time, making measurement impossible. Therefore, it is important to choose a relatively long distance to ensure that results can be successfully obtained. When discussing echo location, humans learn from animals and create sonar technology. Students also came to understand the limitations of humanity in the face of nature, showing a sense of awe towards the natural world. What is even more heartening is that this discussion led students to reflect on philosophical questions such as the need for humility in humans and the dangers of arrogance.