 He explained that while the damage done by a small explosion was proportional to the impulse (the average pressure of the explosion times its duration), the damage from large explosions such as an atomic bomb would be determined by the peak pressure, which depends on the cube root of its energy.Bethe then calculated that a explosion would result in an overpressure of at , and therefore result in severe damage within that radius.Von Neumann also suggested that, because pressure increases when shock waves bounce off solid objects, the damage could be increased if the bomb was detonated at an altitude comparable to the damage radius, approximately .