What’s on the Sound poster
The rule, 3 worked examples, and the mistake everyone makes.
- Sound intensity level in decibels is ten times the logarithm of the intensity ratio.
- L = 10 log₁₀(I/I₀) · I₀ = 10⁻¹² W/m²
- +10 dB = 10× the intensity
- +20 dB = 100× the intensity
- Doubling intensity = +3 dB
- Common mistake: Adding decibels arithmetically → Converting to intensity, adding, con…
Intensity falls as an inverse square with distance from a point source: doubling the distance quarters the intensity.
Questions about the Sound poster
- What’s on the Sound poster?
- The rule, 3 worked examples, and the mistake everyone makes. Sound intensity level in decibels is ten times the logarithm of the intensity ratio.; L = 10 log₁₀(I/I₀) · I₀ = 10⁻¹² W/m²; +10 dB = 10× the intensity; +20 dB = 100× the intensity; Doubling intensity = +3 dB; Common mistake: Adding decibels arithmetically → Converting to intensity, adding, con…. Intensity falls as an inverse square with distance from a point source: doubling the distance quarters the intensity.
- Who is the Sound poster for?
- Sound belongs to the Physics section rather than to a school year, because physical science is not something one grade owns. Anyone learning waves & optics can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Sound poster?
- Every 10 dB is a tenfold increase in intensity and roughly a doubling in perceived loudness. A wall chart earns its place by being glanceable from where the work is happening, so Sound belongs on the wall where that physical science work actually happens, within glancing distance, rather than filed away.
- What other posters go with Sound?
- Diffraction Gratings, The Doppler Effect and Lenses sit alongside Sound in the Physics section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Diffraction GratingsThe Doppler EffectLenses
- Is the Sound poster free to download and print?
- Yes. Sound downloads as a free PDF with no account, no email and no watermark, like everything else in the Physics section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Sound poster print at?
- Sound is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Sound loses nothing.Printing guide
Related posters
Charts that sit alongside Sound on the same wall.
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