Why does a piccolo sound higher and shriller than a flute?

The piccolo sounds higher and shriller than a standard concert flute primarily because of its physical dimensions and design. As a smaller woodwind instrument, the piccolo is constructed with a shorter tube length, which dictates its fundamental pitch; specifically, it is pitched one octave higher than the ordinary concert flute.12

The distinct "shrill" quality, or timbre, of the instrument is a result of how its tube shape and size influence the harmonic series and the strength of various partials. In any wind instrument, the air column is set into vibration to produce sound waves, and the specific proportions of the instrument determine which frequencies are emphasized. Because the piccolo is significantly smaller, its air column vibrates at a much higher frequency, resulting in the characteristic high-pitched, piercing sound that distinguishes it from its larger counterpart.31