Acoustic Levitation - Acoustic Levitation Demonstration

Light objects can be acoustically levitated using a resonate tube and a ping pong ball.
The ping pong ball will ascend when Dr. Andres Larraza changes the frequency from one pressure node to the next.
What's a pressure node?
One characteristic of every standing wave pattern is that there are points along the medium that appear to be standing still. These points, sometimes described as points of no displacement, are referred to as nodes. There are other points along the medium that undergo vibrations between a large positive and large negative displacement. These are the points that undergo the maximum displacement during each vibrational cycle of the standing wave. In a sense, these points are the opposite of nodes, and so they are called antinodes. A standing wave pattern always consists of an alternating pattern of nodes and antinodes. When a standing wave pattern is established in a medium, the nodes and the antinodes are always located at the same position along the medium; they are standing still. It is this characteristic that has earned the pattern the name standing wave. - www.physicsclas...
Acoustic Levitation
• Acoustic Levitation - ...