A movie that raises an object using ultrasonic waves

Although it is a hard to believe sight, various things such as balls, water, insects are emerging. It is possible not only to emerge, but also to rotate and to stop.

What is the principle on earth ...?

Details are as follows.YouTube - Acoustic Levitation Chamber

The water is floating. Variable shape deformable
YouTube - Ultrasonic Levitation


Ali is floating
YouTube - Acoustic Levitation Chamber


This kind of phenomenon seems to be called "ultrasonic floating", and by letting the radiation pressure generated by ultrasonic waves be reflected by a reflecting plate or the like, the object is levitated to a fixed position of the space without contact and held It seems to be able to do.

By the way, I was concerned about whether you could float a human being, but if you look at places you are not practicing, the equipment that can float big things like human beings will be a terrible size, or humans Is it impossible because the body can not tolerate the powerful ultrasound so far?

For the ultrasonic wave, the following link is detailed

Ultrasonic - Wikipedia