Answer:
The rate of vibrations of the atoms is consistent
Step-by-step explanation:
A second is defined as 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
The definition applies when the atom is in isolation at a temperature of absolute zero. Adjustments must be made for the conditions that can be maintained in practice.
Such radiation is determined by the laws of quantum mechanics, so is extremely consistent.