THE SCIENCE BEHIND THE PING
Coin resonance visualizer
See the motion behind a coin’s ring. Explore a gold Krugerrand in 3D, one resonance at a time.
Drag to rotate · Shift-drag to pan · Scroll to zoom
Now listen to your coin.
This is an illustration. Use Pingcoin to compare your coin’s sound with its reference frequencies.
Why does a coin ring?
A tap excites several natural vibration patterns at once. Each pattern has its own frequency. Together, they produce the sound you hear as a ping. This visualizer isolates one pattern so you can see what is moving.
What are the lines that barely move?
They are nodes. In the colored view, regions on either side of a nodal line move in opposite directions. The c0d2, c0d3 and c0d4 labels describe patterns with zero nodal circles and two, three or four nodal diameters. The c1d0 pattern has one nodal circle.
Why only four choices?
The first six computed elastic eigenvectors contain repeated frequencies. In a perfectly circular model, rotated orientations can have the same frequency. We show one representative orientation for each distinct resonance.
Prediction versus Pingcoin reference
For the three matching families, the uniform-disk model is within 2.65% of the published reference. This agreement is not an authentication result.
| Family | Model | Pingcoin | Difference |
|---|---|---|---|
| c0d2 | 4733.8 | 4862.6 | -2.65% |
| c0d3 | 10773.6 | 10925.9 | -1.39% |
| c0d4 | 18421.9 | 18596.6 | -0.94% |
Difference = model ÷ reference − 1. Reference snapshot: 4 September 2026, from the Krugerrand verifier. No reference is supplied here for c1d0. Frequencies are not fitted to the references.
Coin photographs: Gruener Panda / CoinInvest, CC BY-SA 4.0. Photographs are mapped onto the deforming surface.
