Sound is indeed the result of atoms or molecules vibrating and transferring energy through a medium, such as air, water, or solids. However, the perception of distinct noises instead of a single noise varying in intensity is due to several factors:
Frequency: Sound waves consist of vibrations that occur at specific frequencies. Different frequencies correspond to different pitches of sound. For example, a high-pitched sound like a whistle has a higher frequency compared to a low-pitched sound like a drum. The variation in frequency allows us to perceive different tones and pitches, contributing to the distinction between sounds.
Amplitude: The amplitude of a sound wave determines its intensity or volume. Sounds with larger amplitude produce louder sounds, while sounds with smaller amplitude are quieter. By varying the amplitude, we can perceive sounds as soft or loud, further contributing to the distinction between different noises.
Harmonics: Many sounds are composed of a fundamental frequency along with multiple harmonics. Harmonics are integer multiples of the fundamental frequency and give sounds their unique timbre or quality. The presence and relative strength of different harmonics in a sound determine its characteristic tone and distinguish it from other sounds.
Duration and temporal patterns: The duration of a sound, along with its temporal pattern, also plays a role in distinguishing one sound from another. Different sounds have specific temporal characteristics, such as attack, sustain, and decay, which influence their perceived qualities.
Combining these factors, our auditory system processes and interprets the complex patterns of sound waves, allowing us to perceive a wide range of distinct noises rather than just a single noise varying in intensity. The intricate mechanisms of our ears and brain work together to analyze the different acoustic features and construct our perception of the diverse soundscape around us.