Arsenic. It's actually essential to life for some really exotic deep-sea life (taking the place of phosphorus).
Elemental Mischief:
Beryllium vs. Boron
I like that article. It seems to me that as our world has become ever more technologically advanced, we humans have started to lose connection with each other. Education is (nominally) preparing students for a competitive job market, but is not really preparing them to be functional human beings. One of the big foci at this conference was all students--not just the high achievers or the ones we happen to like personally--need to feel like they have the opportunity and the support to be successful.
Roasting smells better, tastes better, and results in lower fat. (I will not disparage deep-fried turkeys at Thanksgiving, however.)
More Useful for Teachers:
Calcium carbonate as chalk vs. Calcium carbonate as an antacid (Tums, frex)
Funny, I just spent three days in a conference on pretty much this exact question. The correct answer (at least in the context of teaching) is cooperation.
Chalk board vs. White board
There's a local ice cream maker called Farr's whose products are of similar quality, but at a much lower price.
Tillamook also makes really, really good ice cream.
For root beer floats, though, the store brand is generally quite sufficient.
Okay, I'll say that Thanksgiving Day games in Detroit and Dallas would be acceptable, but only if the four teams involved have a bye week the Sunday before.
I have now officially survived three days of the Professional Learning Communities conference, as well as two days of parent-teacher conferences, including those for my own two kids. Now I have a 3-day weekend ahead of me. Life is good.