正在确认阅读权限…
What Causes the ‘Barking’ Sound of Some Sand Dunes?
是什么导致某些沙丘发出‘吠叫’般的声音？
精读先不看文字，完整听一遍。
-
Singing or booming dunes produce loud, low-frequency sounds that resemble distant thunder or foghorns.鸣沙或轰鸣沙丘会发出类似远处雷声或雾号的响亮低频声音。
-
This phenomenon occurs only when sand grains are nearly identical in size, roundness, and silica content.这种现象仅发生在沙粒大小、圆度和二氧化硅含量几乎完全相同时。
-
As layers of sand avalanche down a slope, synchronized grain vibrations generate standing sound waves.当沙层沿斜坡崩落时，沙粒同步振动产生驻声波。
-
The dune itself acts like a natural amplifier, resonating at frequencies between 70 and 105 Hz.沙丘本身如同天然放大器，在70至105赫兹频率范围内共振。
-
Scientists confirmed this by measuring vibrations with geophones buried beneath active slip faces.科学家通过在活跃滑动面下方埋设地震检波器测量振动，证实了这一点。
-
Dryness is essential: even slight humidity dampens grain motion and silences the effect instantly.干燥至关重要：即使轻微湿度也会抑制沙粒运动，立即消除声响。
-
Only about 30 locations worldwide host reliably singing dunes, mostly in deserts of Morocco, China, and the USA.全球仅有约30处地点拥有稳定鸣沙的沙丘，主要分布于摩洛哥、中国和美国的沙漠中。
-
Wind alone doesn’t trigger it — human footsteps or small slides often initiate the acoustic cascade.单靠风力无法触发该现象——人类脚步或小型滑落常引发声学级联效应。
-
Laboratory experiments show that grain coatings of clay or salt prevent synchronization and stop the sound.实验室实验表明，黏土或盐分涂层会阻碍沙粒同步振动，从而抑制发声。
-
Understanding this helps geophysicists model granular flow in landslides and planetary surfaces like Mars.理解这一机制有助于地球物理学家模拟滑坡及火星等地外表面的颗粒流动。
精读 · 大约 10 分钟
听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。
③ 学 · 重点表达
- Scientists confirmed this by measuring vibrations with geophones buried beneath active slip faces. 科学家通过在活跃滑动面下方埋设地震检波器测量振动，证实了这一点。
- Singing or booming dunes produce loud, low-frequency sounds that resemble distant thunder or foghorns. 鸣沙或轰鸣沙丘会发出类似远处雷声或雾号的响亮低频声音。
- Dryness is essential: even slight humidity dampens grain motion and silences the effect instantly. 干燥至关重要：即使轻微湿度也会抑制沙粒运动，立即消除声响。
④ 懂 · 选一选
⑤ 今天会说这一句
Scientists confirmed this by measuring vibrations with geophones buried beneath active slip faces.
⑥ 跟读并录音
Scientists confirmed this by measuring vibrations with geophones buried beneath active slip faces.
第一版：录下来、回听、再听标准音。系统打分以后再加。
⑦ 说 · 自己来一句
用今天的表达，自己说一句。
例子：Scientists confirmed this by measuring vibrations with geophones buried beneath active slip faces.
已记下。连续天数以后会显示在课表里。
陈老师指导
课程开发中，敬请期待。成人和孩子都可以先自学听读、精读。
这边的讲解音轨还在做。想先跟着老师走完固定 30 课，可以去陈老师带读社（和自学通行不是同一份会员）。
课程开发中，敬请期待。