Periodic events are events that occur at a regular periodic interval of time. Periodic occurrences, such as a vibrating tuning fork, the sun rising and setting, and ocean waves, may occur at precisely equal time intervals (Norris, 2018). Each time a motion is repeated or cycled, the time interval between repetitions or cycles is referred to as a period, and the frequency at which these periods occur is measured in units of time. Thus, the Earth’s orbit has one year and a one-year frequency. The 12-hour cycle of rising sun and setting is called the diurnal cycle. One millisecond is equal to 1,000 cycles per second for a tuning fork, and therefore it has a period frequency of 1000 cycles per second (Kramer & Brown, 2018). The time interval between one occurrence of a periodic event and the next is definite.
The sun rising and setting activity is one example of a periodic event. The rising of the sun refers to the emergence of the sun to the horizon, whereas the setting of the sun refers to the disappearance of the circumferential edge of the sun from the horizon. Time intervals between the rising and the sun’s setting are regular in the sense that they are easily predictable. When the sun rises one day, it is expected that the sun will also rise the next day. Additionally, the number of hours that pass between one sunset and sunrise is closely equal to the hours between the next sunset and sunrise. Similarly, the time difference between the rising of the sun and its setting is almost equal every day. Therefore, how the sun rises and sets in equal time intervals qualifies it as a periodic event.
References
Kramer, S., & Brown, D. K. (2018). Audiology: science to practice. Plural Publishing.
Norris, J. K. (2018). Rhythm Entrainment: An Integrative Theory of Interconnectedness. California Institute of Integral Studies.