Incredibly, the Atomic Bomb Ring really did allow the children of the atomic age to witness the decay of atomic nuclei as they munched their breakfast cereal. Attached to the ring was a bullet-shaped capsule that separated into two halves. As the advert says, one half contained a secret message compartment, but the other half ‘the warhead’ contained a hidden atom chamber. This silver chamber was a device invented four decades earlier by renowned British physicist Sir William Crookes.