The baked bean index and other economic indicators
Many more in the included links.
This does not include* any mention of the vendor gift index; Tuesday’s Lab Snacks included mini Lorna Dunes. They were tasty. (He who opens the package gets first choice). And it was a partial order, so possibly more to come.
*UPDATE: Now it does. I’ve been linked to by Kottke!
What causes the colors of metals like gold?
If an energy level (like the 3d band) holds many more electrons (than other energy levels) then the excitation of electrons from this highly occupied level to above the Fermi level will become quite important. Gold fulfills all the requirements for an intense absorption of light with energy of 2.3 eV (from the 3d band to above the Fermi level). The color we see is yellow, as the corresponding wavelengths are re-emitted. Copper has a strong absorption at a slightly lower energy, with orange being most strongly absorbed and re-emitted. In silver, the absorption peak lies in the ultraviolet region, at about 4 eV. As a result, silver maintains high reflectivity evenly across the visible spectrum, and we see it as a pure white. The lower energies (which in this case contain energies corresponding to the entire visible spectrum of color) are equally absorbed and re-emitted.