I'm sure I'm not the only one who logged onto the computer this morning and wondered why Google had a bunch of lab equipment as their logo. It turns out today is the 200th anniversary of the birth of Robert Bunsen, designer of the gas flame burner we've all used in lab (see a LEGO version by Neodymium-boy below). Bunsen created this gas flame (or improved on previous designs, to be more exact) as part of his study of emission spectra of elements. When you heat up a substance, the energy can bump electrons from lower energy levels up to higher energy levels, putting them at a higher potential energy. This is analogous to lifting a weight - by putting in energy, you are putting the weight at a higher potential energy relative to the earth's gravity. When you let go of the weight, it will fall back down. The same is true of electrons; they will relax from a higher energy state to a lower energy state. That energy has go go somewhere (the conservation of energy tells us that energy is neither created nor destroyed, it simply changes forms), and in many cases it is given off in the form of light. Studying the energy of the light given off tells us about the relative energies of the electrons involved.