The human ear collects sound with a funnel of cartilage and skin called the pinna.

The longer version

The visible flap of skin and cartilage on the side of the head is not decoration. Its ridges, hollows and curved shape gather pressure waves over a wider area than the canal opening alone and steer them inward, while its folds introduce small delays that differ with direction. The canal itself acts as a short tube with a resonance that gently boosts speech-range frequencies.

Those delays are a major cue for telling above from below and front from behind. A listener with a blocked or covered outer ear loses that filtering and finds vertical placement of a noise much harder. Cupping a hand behind the ear exaggerates the same effect and adds a little gain.

Where this entry sits

Sound and Music gathers facts about how vibrations move through air and water, how ears turn them into meaning, and how instruments and notation shape what listeners hear. Expect echoes, pitch, volume, acoustics, and the odd silence in between. The full list sits on the Sound and Music page, where every entry is listed in order.