alt Hacker News> There's zero purpose for having a bottle with any label.
Light interacts quite differently with the label than the material of the bottle. We get to observe scattering, diffusion, color... y'know, science stuff.
It is rather interesting that the first video (from 12 years ago) used a blank red label instead.
(See how it differs in from the rest of the bottle? I particularly like how it obscures the pulse itself and highlights the wavefront on the surface.)