This is an easy to use piece of apparatus for determining the speed of sound in air. The unit contains two sensitive microphones connected to control circuity that will start and stop a millisecond timer. Alternatively the outputs may be monitored on a storage or PC oscilloscope.
In use a sharp sound is produced in line with the two microphones, the time recorded is then the time taken for the sound to travel between the two microphones. Supplied with a 9V PP3 battery, a 6 metre connecting cable and full instructions.