Resonance in Plates, Bars, Solids Concept

Demonstrations in Resonance in Plates, Bars, Solids

Eight graduated wooden bars suspended by twisted cord from a horizontal metal rod, with note letters (C, B, A, G, F, E, D, C) stamped on each bar. A wooden mallet ball hangs from the rod.

Xylophone

Demonstrates pitch dependence on bar length: shorter bars produce higher frequencies. For free bars,, in contrast to strings where.
Person arranging numbered wooden bars across three large wooden support blocks on a lecture table

Tune Playing Blocks

Demonstrates the relationship between bar length and resonant frequency for solid bars. Wooden blocks of different lengths are knocked off a support to play "Home, Sweet Home," making the length-pitch …
Long metal singing rod leaning against a lecture demo table with a red band visible near the midpoint; leather glove, rosin bottle, and wooden mallet rest on the green countertop

Resonance in a Rod

Demonstrates how holding position on a vibrating rod selects which longitudinal standing wave harmonics can persist. Students hear the pitch rise as the hold point moves to positions that enforce …
Four Chladni plates of different shapes — circular, square, triangular, and violin-shaped — each mounted on a clear cylindrical audio driver, showing sand patterns at resonant frequencies

Chladni Figures

Sand on a vibrating plate collects along nodal lines, revealing 2D standing wave patterns. Students see how plate geometry and driving frequency determine the mode shapes, connecting resonance and boundary …
Three circular metal plates of decreasing size suspended by strings from a wooden bar held against a blackboard

Gong

Demonstrates how vibrational frequency depends on size in solid plates. Smaller gongs produce noticeably higher pitch, illustrating that for circular plates. The gongs do not produce well-defined tones, making them …
Full setup: drum shell with fluorescent rubber membrane under UV panel light, with signal generator and amplifier on the right
Safety

Modes of a Drum

Visualizes 2D standing wave modes on a circular membrane driven by a speaker. A fluorescent rubber sheet under UV light reveals nodal patterns as the driving frequency is swept, connecting …
Projected soap film vibrating at a resonant frequency, showing concentric circular nodal rings with iridescent pink, yellow, and green thin-film interference colors against a dark background
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Normal Modes of a Circular Membrane

Visualizes normal mode vibrations of a circular membrane using a speaker-driven soap film and optical projection. Students observe distinct nodal patterns at resonant frequencies, extending standing wave concepts from 1D …
Clear wine glass approximately half-filled with water on a gray surface against a dark background

Singing Wineglass

Demonstrates friction-driven resonance in a wine glass. Running a wet finger around the rim excites the glass at its natural frequency, producing a sustained tone whose pitch depends on the …
Green patina bronze singing bowl with Greek key pattern on rim, two brass handles, filled with water, sitting on bubble wrap

Singing Fountain

Rubbing the handles of a water-filled bronze bowl excites resonant vibrations that produce audible tones and dramatic standing wave patterns in the water. Students observe acoustic resonance, normal modes, and …
A 12-inch Westcott metal ruler with a long loop of white string threaded through a hole at one end, laid on a gray surface
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Bullroarer

A spinning metal ruler on a string produces a rhythmic rumbling sound and demonstrates coupled rotational motions, aerodynamic lift, and sound generation from a vibrating solid.