For this project, instead of trying to quiet his blower, he decided to make one as loud as possible in the form of an air raid siren. The basic idea behind [Matthias]’ air raid siren is to make ...

Air-raid siren sounds the warning. Air-raid sirens first sounded the warning in London in September 1939. They became an almost daily part of life in the capital a year later during the height of ...

Some people hear an air raid siren, and assume there must be an historical war re-enactment taking place nearby. I am the third type of person, who hears a 3D-printed air raid siren and ...

The air raid warning system was developed in 1938/9 ... created by varying the power to the siren. The second was the all clear - a single, continuous note. After it was confirmed the skies ...

Smoke rises following an Israeli bombardment in the Gaza Strip, as seen from southern Israel on Wednesday (Ariel Schalit/AP) The Israeli military says air raid sirens have sounded in several areas ...