The web carries a remarkable amount of nuclear weapon design information, of varying accuracy and provenance. Carey Sublette (I think this is he) has written a popular FAQ; it includes the graph above. What has this to do with change? Well, according to his explanation, if you have to explode a ball of Uranium, you need to squash it smaller. If you squash it enough, it becomes critical and (usually with a little help) starts a chain reaction, leading to an explosion. When you squash anything, it gets hot and tries to expand. Ideally, you would compress it so slowly that the excess heat leaks away as you press. That’s always far too slow for a bomb. The best you might hope to manage is to press steadily, so that all of your effort goes into shrinking the bulk. You’ll know you are being steady enough because, if you steadily release the pressure, the ball will return to its original size and temperature; the compression is reversible or adiabatic. To get enough compression to detonate the bomb, however, you need to use a shell of explosives. Typically, that will not achieve a steady compression; it will create sonic booms or shock waves: enormously powerful sounds that will bounce around the ball, heating it up and making it expand. The ball gets far hotter than you would wish and you need to use too much explosive energy. Brute force generates a great deal more heat than light. In consequence, expert bomb designers use tricks to make the compression as reversible as possible.
There is a universality (the second law of thermodynamics) about the efficiency of steady, reversible, change. I think it applies also in the management of human endeavours. Steady change gets us where we need to be with the minimum of wasted heat and energy. Shock change generates more heat than light, and is inefficient.
INEX REVIEW
The InEx Review is a University-wide review of income and expenditure. As the Vice-Chancellor explained in his letter to staff, (4 April 2008) this is a necessary and unavoidable response to the challenge posed by operating in an increasingly competitive environment at a time when the University’s income is not keeping pace with expenditure.
Shock change has happened to us before; I hope it doesn’t happen again with the PwC review, and the arrival of a new VC, DVC and COO. Whatever happens, UCU will be here to try to keep things as cool as possible.
Denis Nicole
