Here's why:
* Physical Phenomenon: Sound is caused by vibrations that travel through a medium, like air, water, or solids. These vibrations create pressure waves that our ears can detect.
* Sensory Experience: Our brains interpret these pressure waves as sound. We perceive different frequencies of vibrations as different pitches and amplitudes as different volumes.
In summary:
* Sound exists physically as vibrations in a medium.
* Sound exists mentally as our perception and interpretation of those vibrations.
So, sound is both a thing and an idea - a physical phenomenon that we perceive and experience.