Question

Why are there so many holes in a flute?

Answer 1

Hint: A flute is similar to an organ pipe that can be manually closed and opened at one end. This helps in creating different notes necessary to create music

Complete step by step answer:
The flute is an instrument that acts like an organ pipe open at both ends. The two open points of the flute are pressure nodes which means the amplitude of the sound at those points will be zero. This is a consequence of the standing waves that will be generated in the tubes. The frequency of the standing waves will be determined by
 $ f = \dfrac{{nv}}{{2l}} $ where $ v $ is the velocity of the sound wave, $ l $ is the length of the tube and $ n $ are all positive integers.
When we open a hole, it is similar to shortening the length of the pipe as the hole ‘short-circuits’ the flute and a standing wave will be formed between the open end where we place our lips and the first hole.
Similarly, opening different holes will generate different standing waves with different frequencies corresponding to different $ 'n' $ depending on which holes are opened. This is necessary to create different notes of sounds on the flute.
Hence this is why flutes have so many holes.

Note: When all the holes are closed, standing waves will be formed at the two open ends of the flute. It is a common misconception that the end where we place our lips is closed whereas, in reality, it has to be actually open to the atmosphere to form a standing wave.