April 9, 2011, 9:56 am
Show Me the Seiverts
By Henry Woodbury
The Fukushima nuclear reactor remains in crisis. One informational challenges for media and scientists in this disaster has been explaining the relative risks of the radiation levels. The Sievert, a unit that attempts to measure the biological effect of an absorbed dose of radiation, is measured in micro-quantities for such things as a dental x-ray which is about one-millionth of a dose that is deadly. While a mathematician may easily compare very small and very large number as powers of 10, this is hardly intuitive to the rest of us.
Randall Munroe, at xkcd, has created one of the more comprehensive attempts to show radiation risk by charting doses in blocks and associating them with specific examples. Depending on color each unit represents one of four values from 0.05 microSeiverts (blue) to 1 Seivert (yellow). A large set of examples in one color becomes a small unit of comparison in the next:
The chart reads in a clockwise circle; better would be a horizontal left-to-right for both data and key. Still, it is a grand effort that repays close reading.
Check out the link above, great way to tie all this info together. The original XKCD chart is good, but kind of confusing to relate one to another. InformationIsBeautiful (http://www.informationisbeautiful.net/visualizations/radiation-dosage-chart/) published one on a log scale trying to create a continuous spectrum, but this triangle chart is the best one by far since it solves the problem of showing exposure within a time frame.
Posted by jonmcrawford on April 12, 2011 at 10:06 am
@jonmcrawford. Agreed. Those are both really good charts. From a design perspective I think the triangle chart could be made more intuitive, but the way it adds the time element is very compelling.
Posted by Henry Woodbury on April 12, 2011 at 10:32 am