What’s with the egg? The egg is a great example of how different tissues scatter and absorb light differently. The egg white, when its raw, is transparent to visible light. In this case, light would propagate through without loosing its direction and Beer’s law would hold. However, once it is cooked, it becomes highly scattering  and visible light would diffuse through it, similarly to what happens in popcorn or a foggy day. The egg yolk is an good example of how different tissues absorb light differently: it looks yellow because it absorbs most of the other components of visible light, permitting the yellow/orange wavelength (near 590nm) pass through. Other great examples of highly scattering materials are the inside of a surfboard (polyurethane or polystyrene foam), or beer foam. Specifically beer foam (this is another beer, nothing to do with the one from the law): have you ever thought about why foam is white, when a single bubble is transparent? its the collection of transparent bubbles, arranged in a random fashion, that converts it into a multiple scattering system scattering all wavelenghts in random directions. The same happens to the fat in a nice slice of jamon serrano: if you slice it very thin its transparent, but lots ot fat together is highly scattering and thus white!