Chaff (countermeasure)
In the military, chaff is a bundle of small thin pieces of metal which are shot out of an airplane or warship. These thin strips of metal spread out to make many reflections for enemy radar to detect instead of the target. The many reflections also make it harder for radar-guided missiles to hit anything. The chaff tricks the enemy and helps to keep the plane or ship or other target safe. Chaff was invented during World War II. Later radar methods made it less effective but chaff is still used because it is cheap and simple.
Chaff (countermeasure) Media
A Lancaster dropping chaff (the crescent-shaped white cloud on the left of the picture) over Essen during a thousand-bomber raid
Two forms of RAF "Window" radar countermeasure: chopped aluminium wire and paper backed with aluminium foil
Letter from Secretary of the Navy James Forrestal to Merwyn Bly
