Silencers are a necessary part of every secret agent's stock-in-trade-at least as far as the movie-going public is concerned.
Silencers are usually made up of two areas-an expansion chamber and a number of baffles. In the expansion chamber, the hot gas suddenly has more room to move and is able to expand and become cooler and the molecules collide less frequently. This principle is also used for the silencers on motor vehicle exhaust pipes. The baffles in the silencer cause further declaration by causing the hot stream of gas to swirl and -because they are made from metal-they absorb part of its thermal energy.