Physical wave experiments confirm ray tracing and numerical simulation predictions

Evidence

Figure 2.20 Three completely different approaches to the same phenomenon: an off-center point source of waves in a circular enclosure. The left image is a ray tracing, obtained by following rays from the off-center source point outward until they hit the circular walls, and then taking specular bounces. The middle image shows the Ripple simulation with a sinusoidal source. The right-hand image is the most remarkable, obtained in painstaking detail by watching the wave pattern from liquid mercury dropped periodically at the off-center source point in a circular dish of liquid mercury. The original drawing, published in 1826 in Wellenlehre, by Ernst Heinrich Weber and Wilhelm Eduard Weber, consists of about 200,000 individual handmade dots stylistically representing the antinodes as shaded-relief diamonds. Here, we clearly see the relation between two types of modeling (solving numerical equations simulating the waves as in Ripple, and following rays from the source) and the “real thing,” as drawn in 1825 from an experiment. — Eric J. Heller, Why You Hear What You Hear- An…, 217

Categorization

• CANDY: A wave pattern in liquid mercury drawn as roughly 200,000 handmade dots in 1825 that matches modern simulations — a delightful trivia nugget.
• XREF: The Weber brothers’ 1820s experimental wave drawing anticipates modern confirmation of a computational model by a physical analog — mirrors the later ocean tomography claim that ray paths deduced from travel times match reality.