Periodic and Non-periodic Motion
3 Minutes
Periodic and non-periodic motion for kids: learn how repeating and non-repeating movements work through simple daily examples. An English science lesson.
- How Earth's rotation creates day and night
- Periodic motion in a pendulum, Earth, and a moving car
- Non-periodic motion and periodic examples like yawning
What this lesson teaches
Periodic motion is any movement that repeats at regular, fixed intervals of time, whereas non-periodic motion is any movement that does not repeat at regular intervals.
How periodic motion works
A motion is classified as periodic when an object performs the exact same movement over and over within a specific time period. A pendulum provides a clear demonstration by completing one full oscillation every single second. Similarly, a car traveling along a circular path that finishes each round in exactly ten seconds is in periodic motion, because the cycle begins again after every ten-second interval.
Earth rotation and day and night
- The Earth remains in continuous rotational motion, spinning on its own axis.
- It takes exactly twenty-four hours, or one full day, for the Earth to complete one single rotation.
- When one half of the Earth faces the Sun, that half becomes bright, creating daytime.
- The opposite side facing away from the Sun remains dark, creating nighttime.
- If the Earth ever stopped rotating, one side would stay permanently in daytime while the other would stay in nighttime, but this rotation never stops.
Non-periodic motion
Non-periodic motion includes any movement that does not happen again at regular, predictable time intervals. For instance, when a person stands up, walks across a space, and sits down somewhere else, that movement does not repeat. Movements that travel along straight paths, known as linear motion, or along curved paths, known as curvilinear motion, serve as examples of non-periodic motion when they do not repeat.
Everyday examples of periodic motion
- Everyday machines show periodic motion, including a spinning ceiling fan, a running food grinder, and the vibrations of an electric bell.
- Amusement park rides, such as a turning giant wheel at an exhibition and a swinging ride, also repeat their motions regularly.
- The human body relies on periodic motion, seen naturally in the steady beating of a heart.
- In one lesson story, a man named Pattabhi Kumar had an illness where he yawned every five minutes, making his mouth move up and down in a repeating pattern that earned him the nickname Kottavi Kumar, based on the Tamil word for yawn.