Chinese scientists develop handheld sonic weapon for crowd control
- Gas-powered device passed for mass production after two years of research

The rifle-shaped instrument, which was jointly developed with military and law enforcement, is designed to disperse crowds using focused waves of low frequency sound, the academy's Technical Institute of Physics and Chemistry website said on Wednesday.
The device’s “biological effect” would cause extreme discomfort, with vibrations in the eardrums, eyeballs, stomach, liver, and brain, scientists said.
Studies dating to the 1940s found that low frequency sound energy could, depending upon intensity and exposure, cause dizziness, headaches, vomiting, bowel spasms, involuntary defecation, organ damage and heart attacks.

Sonic weapons are typically large and have to be mounted on vehicles. Until the Chinese development, which has no moving parts, they were powered by electricity to drive a magnetic coil to generate energy. This meant they needed a large and stable source of power.
The Chinese government launched the sonic weapon programme in 2017 and its conclusion is unlikely to be related to the months of anti-government protests in Hong Kong.