Grades K–2 · Arts & Music
How does vibration size relate to sound?
A sounding object can shake back and forth so quickly that you cannot follow each move. This vibration pushes and releases nearby air, sending changing pushes through the air as sound.
The wiggles in the drawing show the size of a repeated vibration. Bigger wiggles go farther from the resting line. That size is called amplitude. With the same source and timing, a larger vibration can make stronger changes in the air and generally a louder sound at the same listening distance.
The dotted line marks the resting position, and the orange marker shows how far a wiggle reaches from it. That distance shows amplitude while the wiggle timing stays unchanged.
In the diagramVibration size is called amplitudeSame source, timing and listening distanceThe dotted line is the resting position.A vibration moves away from rest.Smaller amplitude; no exact loudness score.
Smaller vibrations generally make softer sounds when the source, timing, surroundings and listening distance stay the same. Bigger does not mean faster: these wiggles keep the same timing. Their size helps show sound strength separately from how quickly the source vibrates.
About this explanation
Starting knowledge: Distinguish a bigger movement from a smaller one and follow a resting-position picture with adult reading support.
Sources
- OpenStax, Physics — 14.2 Sound Intensity and Sound Level
- OpenStax — 14.1 Speed of Sound, Frequency, and Wavelength