TEST A: EXPLOSION IN AIR 



the havoc wrought. Many masts, for example, were 

 bent by this positive phase; and they certainly were 

 not straightened out again by the ensuing negative 

 (suction) phase. Impulse values — and ship damage 

 — were particularly great because both the pressure 

 and the duration of the positive phase are exceptionally 

 great in atomic bomb explosions. Destruction was far 

 greater than would have resulted from high pressure 

 alone, or long duration alone. The bomb reaped double 

 havoc. 



CONDENSATION CLOUD 



The shock wave was not visible to the naked eye; 

 but the progress of the ensuing suction was apparent 

 enough. Racing closely on the heels of the fast-spread- 

 ing shock wave, the suction wave had the form of a thin 

 shell of rarefied air. Because this air was rarefied and 

 thus cooled, the water molecules present condensed in 

 myriad tiny droplets, millions of them in each cubic 

 inch. 



The result was the formation of a large zone of fog, 

 called the condensation cloud. Some persons referred 

 to it as the "Wilson Cloud," in honor of C. T. R. "Wil- 

 son, who fifty years ago pioneered the study of fog and 

 rain, and made thousands of experiments in which fogs 

 were produced by sudden expansion of saturated vapor. 



From a distance, the condensation cloud at first re- 

 sembled a white hemisphere, dazzlingly bright, resting 

 on the surface of the water. The hemisphere grew rap- 



15 



