Doubling pressure amplitude gives four times the intensity in this controlled model, rather than twice the intensity. This is a physical comparison, not a prediction that a listener experiences four times the loudness. Decibels use logarithmic ratios, which is another reason not to confuse the plotted height with a direct loudness scale.
Light, sound and electricity · Discover & try
How does wave size relate to sound strength?
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amplitude
The size of a repeated change around its middle value.
intensity
Energy flow per unit area in the physical comparison.
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Pressure amplitude and relative intensity at fixed frequency; no real sound level or hearing test.
What to look for
- Amplitude changes height
- Frequency stays fixed
- Relative intensity follows amplitude squared
Explain what you noticed
Pressure amplitude rises from 2 to 6 units in the same medium. By what factor does this model intensity change?
Keep this idea: Wave amplitude and perceived loudness are related but different quantities.
Follow the sources
- NIH Curriculum Supplement — Hearing, Communication, and Understanding
- NIH / NIDCD — How Is Sound Measured?
- OpenStax, Rice University — Sound Intensity and Sound Level
Source material checked 2026-10-29. Explanations and activities by Nepedia. Source links do not imply endorsement.
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