Singing sand, also called "ringing sand", "eliminating sand" or "musical sand", refers to the sound produced by sand, which is a ubiquitous natural phenomenon. In Long Island, Massachusetts Bay, and both sides of Wales in the United States; Northumberland Coast in the United Kingdom; Bornholm Island in Denmark; Kolburg in Poland; as well as the Gobi Desert in Mongolia, the Atacama Desert in Chile, and Saudi Arabia Some of the beaches and deserts make strange sounds. It is said that more than 100 similar beaches and deserts have been discovered in the world.
People find that singing sand is usually found on beaches or deserts. The sound of the sofa is usually made when the wind is sunny or windy, or when someone is sliding on the sand. In humid weather, rainy days and winter, the singing sand generally does not make any sound. In addition, people also found that only clean quartz sand with a diameter of 0.3 to 0.5 mm can make sound, and the drier the sand, the louder the sound.
Singing sand is not only widely distributed in the world, but the sounds produced by the sand are also diverse. For example, the sand on Kaua'i Island in the Hawaiian Islands in the United States makes a sound that sounds like a barking dog, so people call it "barking sand"; the sand on Egg Island in Scotland makes a sharp and loud sound. It's as if the index finger has played on a taut silk string; when rolling down the Mingsha Mountain in China, the sand will make a loud rumble, like thunder.
China also has three famous Mingsha Lands. The first one is Mingsha Mountain 6,000 meters south of Dunhuang County, Gansu Province. It was recorded in two books, "Taiping Yulan" and "Taishozo". At that time, it was called "Shensha Mountain" and "Shajiao Mountain". Mingsha Mountain is about 40 kilometers long from east to west, about 20 kilometers wide from north to south, and tens of meters high. The peaks are steep. Its northern foot is the famous Crescent Moon Spring.
If you climb Mingsha Mountain and look down, you will see sand dunes one after another; if you slide down the sand from the top of the mountain, the sand will make bursts of sound. According to historical records, when the weather is fine, there will be the sound of silk and bamboo strings on Mingsha Mountain, as if playing music, so people call it "Sand Mountain Qingming", which is also a major landscape in Dunhuang.
There is another legend about Mingsha Mountain. In ancient times, a general led his army to fight and once camped here. One night, a strong wind suddenly blew in the sky. Yellow sand flew all over the sky, covering the sky and the earth, and gods and ghosts cried. After the wind stopped, the generals and soldiers were all buried under the long yellow sand, and no one could survive. Later, people often heard the sound of drums and horns coming from the sand on the mountain, as if the general was leading the army to march and fight, so people called it "Mingsha Mountain".
The second Mingsha Land in China is the Mingsha Mountain on the bank of the Yellow River in Shapotou, Zhongwei County, Ningxia Hui Autonomous Region. The famous Chinese scientist Zhu Kezhen described it in the article "Strange Phenomenon in the Desert": "The sand is about 100 meters high. The sand slope faces south and north, and is concave in the middle. There are many springs gushing out. This sandy land has always been... The object of people's worship. It is said that during the Dragon Boat Festival, men and women will hear a loud roar like thunder from this sandy land.
The third sandy land is located in Kubul. Xiangsha Bay on both sides of Mohan Taichuan River. Xiangshawan is located 25 kilometers south of Dalat Banner in Inner Mongolia Autonomous Region. This sand mountain is 60 meters high and 100 meters wide. As soon as you walk into Xiangshawan, you will hear various sounds, some of which are like the deep music played by an accordion, making you cry; some are like the tinkling of silver bells, which is so intoxicating.
What causes the sand to make various noises? In ancient times, due to the underdevelopment of science, people thought it was the work of ghosts and the screams of the devil from hell. Now that science has developed, can we use scientific methods? How to explain this phenomenon? So, through research and experiments, scientists have put forward various opinions.
Some people think that there is air in the gaps between sand grains, and when the air moves, It is equivalent to forming "speakers". When the sand dunes collapse, the air flows in and out of the gaps, which will cause the air to vibrate. When the air vibration frequency coincides with this invisible "speaker", it will resonate.
Some people believe that due to the long-term blowing of sand grains in different wind directions, they become uniform in size, very clean, and have holes like honeycombs. The sound of singing sand may be caused by the friction and vibration between sand grains with a unique surface structure.
A scientist from the former Soviet Union was inspecting Kalgan in the former Soviet Union. After hearing the sound of sand, he put forward such a view. He believed that there is a dense and moist sand layer inside each dune, and its depth changes with the amount of rain. When there is a lot of rain in summer, it is wet. The deeper layer is completely covered by the upper sand layer, and underneath the moist layer is a dry sand layer, which may form a natural sound box when the dune collapses and the sand moves along the slope. When sliding down, the vibration waves of the dry sand particles will be transmitted to the moist layer, which will cause the sound of the sand particles to amplify countless times and make a huge sound.
Another scholar from the former Soviet Union. After inspecting Mingsha Mountain in Ningxia, my country, and Xiangshawan in Inner Mongolia, he found that these two Mingsha areas are fine sand tip, and the quartz sand in them accounts for more than 1/2. According to this, he believes that there is some in the quartz sand. Quartz crystal.
Quartz crystals have special piezoelectric properties that make these quartz grains in the sand very sensitive to pressure. As long as it is squeezed, it will be charged, and under the action of electricity, it will stretch and vibrate back and forth. The more severe the vibration, the higher the voltage generated; the higher the voltage, the more severe the vibration. In this way, the sand will make a wonderful sound.
However, quartz sand is widely distributed, but ringing sand is not that common. Moreover, if the place of the ringing sand changes, it will become "dumb" and will not make any sound. Therefore, some people believe that the formation of Mingsha is also related to the special local geographical environment.
In 1979, Chinese scholars proposed new insights. It is believed that the "sounding box" that rings the sand is not underground, but in the air above the ground. There should be three conditions for the sound of the sand dune. ① The sand dune must be tall and steep; ② The leeward slope faces the sun, and the sand surface on the leeward slope must be crescent-shaped; ③ There must be water seeping out from under the sand dune to form springs and pools, or there must be a large of dry river trough. At the same time, it was also proposed that due to the frequent changes in air humidity, temperature and wind speed, which constantly affect the frequency of the sound of sand grains and the structure of the "sound box", coupled with the frequency changes of the driving force and the sand itself, the sound of the sand grains is The sounds also change frequently.
However, some people do not agree with this view, because the Xiangsha Beach on some foreign coasts is very flat, and there are no high and steep crescent-shaped sand dunes at all, and often only after raining, the surface layer is just Makes a sound when drying. For example, there is Tango Peninsula in the north of Kyoto Prefecture, Japan. There are two sandy beaches on the beach there. The sounds of the two beaches are not only completely different in timbre, but also different in different seasons. Therefore, some Japanese scholars believe that the most important condition for the sound of sand on the beach is to have clean sea water to continuously wash it. If the sea water is dirty, the sand will ring.
It can be seen that there is still no satisfactory answer to the secret of Mingsha. I hope that through continuous exploration, scientists can give us a satisfactory result in the near future.