Imagine you are G.I.Taylor and its the start of The Cold War. Life magazine has just published an amazing high speed photographic sequence of the detonation of an atom bomb. The nation is enthralled by these images, but you see a bit further into the imagery.

The pictures give you the radius of the blast as a function of time.

All that could be important In determining the radius R as a function of time are the initial energy released, E, and the density of the undisturbed medium, Rho.

Thanks to your natural curiosity, you know the value of dimensional analysis and reason that the radius, with dimensions of length, must depend only on E, rho, and t, for which the correct expression can only be:

R(t) = (E/Rho t^2)^(1/5)

Since E/Rho has dimensions of (length)^5/time^2

A log-log plot of r vs t (imagine measuring the radius of the blast and carefully noting time stamps given in the picture captions) gives a slope of 2/5, checking the theory, and E/Rho could be obtained from extrapolation to the value of log R when log t= 0. Rho is known For air and thus E was determined to within a factor of order 1.

For the practitioner of dimensional analysis, the nations deepest secret had been published in Life magazine. (Goldstein States of Matter, chapter 6)

Ah, but how best to convey the findings? Surely the best way is to use a mathcad like, But open source tool which prints straight to latex!

Ah ...if only it could express fractional units...

GI Taylor prepares a letter to John wheeler, requesting a closed time like networked computing device so that the feature request can be made.

In all seriousness though, This project is awesome! Just kick in fractional unit support and it will surely be unstoppable.