The entire catenary from New York to  DC was built to carry power at 25 hz—a different frequency than the rest of the American power  grid would eventually adopt at 60 hz.

从纽约到华盛顿特区的整条接触网的输电频率为 25 Hz，与美国电网其他部分最终采用的 60 Hz 频率不同。

And we played sound at a little strand of spider silk and found that when the silk is very thin, it moves with the air in a sound field amazingly well over a wide range of frequencies, from 1 hz to 50 khz.

我们在一根细小的蛛丝上播放声音，发现当蛛丝很薄时，它会与声场中的空气一起运动，频率范围很广，从1赫兹到50千赫。