Grounding beliefs in data
Tom Fiddaman published State CO2 Emisssions from Fossil Fuel Combustion on many eyes. Click through to the interactive version, and see if you find any surprises.
One set of lessons: it appears that industrial emissions have improved between 1990 and 2005 in about half the states of the USA. Emissions from electric power generation have increased in all but four states (all in the Northeast), and emissions from transportation have increased in all states but Kansas.
It would be interesting to see these results expressed in per capita terms, too.
While we're talking about data, see his experiments with his kids on how fast a bathtub drains. Before you do, though, what do you think a time series graph of the water left in a bathtub as it drains would look like? Then read the results.
To me, the bathtub experiment sounds a bit like Seth Robert's self-experimentation, which leads to the obvious thought that we can all be amateur scientists, if we want.