A scavenger hunt using ultrasonic geocaches

Sound is commonly used for either communication or navigation. An ultrasonic scavenger hunt was designed that does both and is designed to raise awareness about acoustics. This scavenger hunts utilizes ultrasonic geocaches to both give information to the participants and educate them on topics including, the fact that sound may not be audible, the concept of hearing loss, other animals hear at different frequencies, and general facts from the hosting event. The geocaches use the frequency band above typical human hearing but still within the bandwidth of most personal electronics, 20 kHz–22 kHz. This band can be picked up by common smartphones and tablets and viewed using free spectrogram applications. The maximum sound pressure level output by the geocache devices falls below maximum public exposure recommendations but the signal is still visible on a spectrogram. The scavenger hunt was trialed at a science engagement event at the University of Southampton with over 6000 in attendance.