If you have not watched this viral video that was uploaded few days ago, you should definitely do so now! As simple as this experiment is in terms of equipment, preparation and environment that is being conducted in, it arouses much excitement and wonderment.
What you are seeing is a tone generator, a wave driver (speaker) and a metal plate attached to it. First, tiny grains of solid material such as salt or sand are added and then a tone is being played. The patterns that appeared are known as "Chladni Figures" and they tend to change in shape and increase in complexity as the frequency of vibration (Hz) goes higher. This geometric beauty is possible because certain frequencies vibrate the metal plate in way that leaves "quiet" areas making place for elegant shapes to be created.
The first experiment of this kind was conducted by Ernst Chladni also now known as "the father of acoustics" in the late 18th century. Some of his studies focused on finding and demonstrating the connection between sound, vibration and physical reality. In other words, his experiment was a visible example of waves interacting with solid materials.
Chladni used a metal plate covered with sand or other fine particles that he excited with a violin bow. The result was a number of archetypal geometric patterns which depend on the position of the bow against the plate. They became known as "Cladni's Figures".
Later on, Ernst Chladni went on a tour across Europe to perform this astonishing phenomenon in front of live audiences. His work was highly praised by many scholars as well as the famous Napoleon Bonaparte who was so fascinated by this experiment that he kindly rewarded Cladni with 6000 francs which today is equal to 30 000 dollars.