Zzzeee goes the tiny mosquito as it zips past your ear. VROOOM growls a big tractor as it rumbles past you. The sound the mosquito makes is much higher than the sound of the tractor. When something vibrates, sound travels outwards from it in waves. Each vibration – each complete back-and-forth motion – makes a single sound wave. The faster something vibrates, the more sound waves it makes and the higher the pitch.
A mosquito makes high-pitched sounds because its wings vibrate very fast – about a thousand times a second!
A tractor makes low-pitched sounds because its heavy metal parts vibrate slowly. The slow vibrations make only a few sound waves every second – the low rumble that you hear.
Picture Credit : Google
