[USMA:37889] Joules, BTU's and Quads

[Bill Hooper]

I have sent the following letter to the editor of the article  
recently printed in the 2007January edition of the IEEE on-line  
publication "Spectrum", titled "Joules, BTUs, Quads—Let's Call the  
Whole Thing Off", by Harry Goldstein and William Sweet, and quoted in  
this USMA list.

Your article about the large number of different energy units is  
right in its criticism of the large number of different energy  
units used. But your suggested solution, to create another new one,  
makes the problem worse, not better.

The SI netric unit of energy is the joule, and the SI system  
presents an array of prefixes that allow the joule modified to be  
used for any sizes at all. If the joule is too small for the amount  
of energy you wish to discuss, the exajoule (EJ) is available.

1 EJ = 1 000 000 000 000 000 joules

If that's too big or too small, there are others, like petajooules  
(PJ) and zetajoules (ZJ) and more that are appropriately and  
conveniently larger or smaller. (I don't know which one to suggest  
to use in place of your suggested "cubic mile of oil" because  
nowhere in your article did you specify how much energy there is in  
a cubic mile of oil.)

SI provides all the units we need. We don't need another new one.

Regards,
Bill Hooper
retired professor of physics
(formerly with
The University of Virginia's
  College at Wise)