A bouncing bomb is a bomb designed to bounce to a target across water in a calculated manner to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined, in a similar fashion to a regular naval depth charge. The inventor of the first such bomb was the British engineer Barnes Wallis, whose "Upkeep" bouncing bomb was used in the RAF's Operation Chastise of May 1943 to bounce into German dams and explode underwater, with an effect similar to the underground detonation of the later Grand Slam and Tallboy earthquake bombs, both of which he also invented.
"Upkeep" bouncing bomb at the Imperial War Museum Duxford
Remains of a Highball test prototype recovered from Reculver in 1997, now at Herne Bay Museum
The Möhne dam breached by Upkeep bombs
Highball bouncing bomb prototype, now on display at Abbotsbury Swannery in Dorset
A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects. Bombs have been utilized since the 11th century starting in East Asia.
An iron grenade with a wooden fuse from 1580
A "wind-and-dust" bomb depicted in the Ming Dynasty book Huolongjing. The pot contains a tube of gunpowder, and was thrown at invaders.
An illustration depicting bombs thrown at Manchu assault ladders during the siege of Ningyuan, from the book Thai Tsu Shih Lu Thu (Veritable Records of the Great Ancestor) written in 1635. The bombs are known as "thunder crash bombs."
Thunder crash bombs from the Mongol invasions of Japan (13th century) that were excavated from a shipwreck near the Liancourt Rocks