In filmmaking, internal rhythm is created by whatever appears or occurs within the shot of a moving picture.
[1] The scene in the newspaper office begins slowly and quietly but gradually speeds up until the action becomes frantic.
The demolition of Susan's bedroom starts off at a slow pace, becomes chaotic, and then slows once more when Charles finds Susan's snow-scene paperweight.
The rhythm of the scene between Kane and Susan at home is heavy and static, yet filled with tension.
It represents a duration where the action unfolds like a dance.