We just found UnitConversion.org, an online unit converter with auto-complete and a pretty large database of odd units. It looks like a a great tool, although it is inexplicably lacking the Debye (which we were trying to convert to electron Angstroms).
My favorite scientific unit has always been the barn (1 barn = 10-24 cm2), which is a unit of cross-sectional area. I.e. hitting this nucleus should be as easy as hitting the side of a barn… Quadrupole moments can be expressed as electron-barns, and our group code uses this unit internally just because it amuses us.
It is interesting to note the following conversions:
- 1 barn = 1.072505996 x 10-36 township
- 1 barn = 1.544408634 x 10-34 homestead
- 1 barn = 2.471053815 x 10-32 acre
Apparently, physicists have very small farms.
Are you also aware of http://www.onlineconversion.com?
Check out Frink
It seems to cover most unit conversions and a lot of useful math, physics, etc. Even better, you can download the Java for desktop use (alas, it’s not currently open source).
I’m the developer of Frink, and I just found this in my referrer logs. I noticed, ironically, that the conversions you cite are all three slightly wrong.
They apparently make the common but very wrong error of not using *survey* feet or statute miles in defining the acre, township, or homestead. The survey foot is larger than the “international” foot by a factor of exactly 500000/499999, (same factor is true for statute mile/”international” mile.) The exact conversion for barn->acre is exactly:
15499969/627264000000000000000000000000000000000 (approx. 2.4710439304662786e-32)
You’ll find Frink to be better-researched and more authoritative, I hope.
Checkout this auto complete unit converter that understand the units as mathematical expressions