Simple harmonic motion facts for kids
A thing that moves back and forth, like a swing, is called a vibration or an oscillation. A special type of this movement is known as simple harmonic motion (SHM).
Imagine you are watching something move. If you plot its position over time on a graph, and the line looks like a smooth, wavy pattern (a sine wave), then it's likely moving in simple harmonic motion. This kind of movement happens when the force pulling the object back to its starting point gets stronger the further it moves away. This force always tries to bring it back to the center.
Good examples of simple harmonic motion include a weight bouncing on a spring or a pendulum swinging back and forth (as long as it doesn't swing too wide). These are not perfectly simple harmonic, but they are very close!
In simple harmonic motion, the amplitude is the largest distance the object moves from its central, resting position. The period is the time it takes for the object to complete one full back-and-forth cycle and return to its starting point, moving in the same direction.
Understanding Simple Harmonic Motion
Simple harmonic motion happens when an object moves around a central point. The force pulling it back to this center is directly related to how far it has moved away. This means if it moves twice as far, the force pulling it back is also twice as strong. This force always points towards the center.
Think of a spring: the more you stretch it, the harder it pulls back. The more you compress it, the harder it pushes out. This push or pull is what creates simple harmonic motion.
How We Describe SHM
We can describe simple harmonic motion using ideas from a spinning wheel. Imagine a wheel with a radius (distance from center to edge) called A. If this wheel spins at a steady speed, a point on its edge will move up and down.
If you watch a white spot on the rim of this spinning wheel, its height above the center of the wheel changes over time. This height can be described using a mathematical idea called the sine function. This is how scientists use math to understand and predict how things move in simple harmonic motion.
Images for kids
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Simple harmonic motion shown both in real space and phase space. The orbit is periodic.
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An undamped spring–mass system undergoes simple harmonic motion.
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The motion of an undamped pendulum approximates to simple harmonic motion if oscillation is small.
See also
In Spanish: Movimiento armónico simple para niños
