ricocheting

Ricocheting is the rebound of a moving object after striking a surface, causing the object to change direction rather than come to rest or embed. It commonly involves projectiles, balls, or stones and can occur on hard, smooth surfaces or at interfaces between different materials.

The underlying physics is often described by the law of reflection for idealized cases: the angle of incidence is equal to the angle of reflection, and the normal component of velocity reverses while the tangential component is affected by friction. In real situations, surfaces deform, heat and sound are generated, and some kinetic energy is lost. This can alter the rebound angle, reduce speed, impart spin, or cause the object to tumble or break apart.

Several factors influence ricochets. The angle of incidence relative to the surface is crucial; shallow or grazing angles are more likely to produce a ricochet, especially on hard, smooth surfaces. The material properties of both the projectile and the surface—elasticity, hardness, and roughness—determine how much energy is conserved and how the surface interacts with the impact. Speed, spin, and the presence of coatings or barriers also play roles, as does the presence of multiple impacts if the object encounters a layered or irregular surface.

Common contexts include billiards, where balls ricochet off cushions, and ballistics, where bullets or shrapnel may rebound off armor, rock faces, or water. Ricochets can be unpredictable and dangerous, which is why appropriate safety measures and backstops are emphasized in shooting ranges and environments where high-velocity impacts occur.