Today, I learned about a frequency of babies cry.
The frequency is always 440 Hz, which is the music node A (also called la).
Surprisingly, this law can be applied for not only human babies, but also babies of every mammal.
The reason why the frequency is constant has not been revealed yet, but there are some hypotheses.
According to the one hypothesis, the frequency 440 Hz is stimulate us, and babies seem to try to wake us.
By the way, orchestras tune their instruments using the music node A(440 Hz).
Also, the international standard pitch has been determined to 440 Hz at the conference in London.
