Yes, they do synchronize and yes, the number of cycles averaged over a day cycle is kept close to constant but: the frequency still floats. In fact, it floats e

Yes, they do synchronize and yes, the number of cycles averaged over a day cycle is kept close to constant but: the frequency still floats. In fact, it floats enough to produce a unique "background hum fingerprint" which can be used to verify authenticity of audio recordings: http://www.bbc.co.uk/news/science-environment-20629671 http://www.bbc.co.uk/news/science-environment-20629671