In the northwestern Chinese province of Gansu is the city of Dunhuang, famous for its singing sand dunes. This phenomenon makes the stunningly high sand dunes “sing” in the wind, creating incredibly beautiful music.
The singing sand dunes are the center of many Chinese legends and folklore and are located along the famous Silk Road, an important trade route between Central Asia and Europe. They are also among the most culturally significant singing sand dunes in China.
Legend has it that the area was once a mountainous region where the Crescent Lake, which still sits at the foot of the dunes, was surrounded by sacred temples. Some believe that the sounds of worship coming from the temples disturbed the Yellow Dragon Prince sleeping in the nearby desert, who in his anger filled the region and all its inhabitants with sand. It is said that the music heard from the dunes comes from those buried within.
However, the scientific explanation for this phenomenon lies in a number of specific qualities that sand dunes possess. The quality of the sand grains is only one of the components that make the dunes sing. They are composed of small and medium particles, their size ensures the best movement and interaction of the grains. This, combined with their shape, creates different resonances and frequencies, and the smooth round fibers create a better sound.
Dune shaping can also contribute to their sound, as the steepness of the slope affects the degree of interaction between the sand particles. And, of course, you need the right wind conditions to blow the particles just enough to create sound – when the wind is strong, the dunes make a loud roar, and when the wind is light, the hills make gentle music.
Surrounding structures can also create and amplify noise, as the mountains and hills create channels of airflow that direct the wind to certain areas around the dunes. When the wind disturbs the grains, it creates friction, which in turn causes the sand to vibrate, creating noise. In addition, the air cavities between the grains can work as resonating chambers that amplify the sound.
Arid climates also contribute to their sound, which is why singing dunes are found in desert environments. Low humidity levels increase friction between grains, creating sound as they rub against each other.
Structural and destructive interference with sand vibrations can create standing waves. These are stationary wave structures with fixed ridges and troughs. The combination of grain vibrations, resonance, and air cavities creates the characteristic sound of dunes.
In conclusion, the singing sand dunes of Dunhuang are a unique natural phenomenon that never ceases to amaze people with its beauty and mystery. Legends and folklore add to the atmosphere of this picturesque landscape, but the scientific explanation of the phenomenon also captures the imagination.