M2 Radiation Calculator (Front) Given the exposure rate (rads/hr) at a given time after a nuclear detonation the calculator can be used to predicts the exposure rate at any other time. It can also estimate the radiation exposure of personnel who are in the area at some time after the explosion.
The Slide Rule: A Computing Device That Put A Man On The Moon. "For generations of engineers, technicians and scientists, the slide rule was an essential part of their daily lives. Until, all of a sudden, it wasn't. In 1972 Hewlett-Packard came out with the first handheld electronic calculator. Practically overnight, the slide rule had become obsolete."