Until World War II, the main types of sirens used were church bells. This began to change, however, in the year 1799 when a Scottish physicist by the name of John Robison invented the siren. His invention was not intended to be a warning device, but to be a musical instrument. Interestingly enough, the design for his musical instrument became the blueprint for future sirens. It used a stationary disk and a second rotating disk, which periodically interrupted airflow creating a “siren” like sound (Beyer 1998).
With the availability of electricity came the creation of electrically powered sirens in the late 19th century; these new sirens were intended as warning devices. Now, sirens no longer had to be driven by external sources of compressed air, but could be run by an electrical motor to maximize the strength and pitch of the siren. The first company to mass-produce sirens was Sterling (Beyer 1998).
Sirens in World War II
In World War II bells and electrical sirens were used across Europe as warning signals, the most classic example being England. During the war the use of church bells in England alarmed residents of a German invasion. To accomplish this, it was ordered that all churches throughout England silence their bells until an attack was immanent, to avoid confusion (Cleary et al. 2005). However, along with bells, mechanical sirens were also used strictly for military purposes.
By the end of World War II, with the increasing production of sirens and availability of electricity, electrical sirens became the norm and fully replaced the more primitive types of sirens, namely bells and air driven devices.
History of Tornado Warning
In the United States and in many places across the world sirens became commonplace following World War II.
In the late 19th century the US army was studying the science behind tornadoes and further study was being done by the National Weather Bureau on how and if to warn the public. It was decided in 1887 that there should be no warnings issued for tornadoes, even the mention of the word “tornado” was banned. They believed that these warnings would only cause more chaos and harm. This ban on tornado warnings was held up until 1938. This all changed when in 1948 a tornado ripped through Tinker Air Force base in Oklahoma killing many people and causing millions of dollars of damage (Coleman et al. 2011).
In 1950, in response to the onset of the Cold War and the threat of atomic warfare, Harry Truman signed into legislation the Civil Defense Act. Part of this bill was the use of large outdoor sirens. The first large inner-city siren was tested in Detroit Michigan and was a Chrysler product (Coleman et al. 2011). At first these sirens were used to warn against nuclear attack during the Cold War (Weible 2008). In 1970 these same sirens were given a second responsibility, to warn people of tornadoes (Coleman et al. 2011). Once the Cold War ended, sirens were now completely used for tornado warnings.