What is a cymatic water-sound-motion?
Water in a round cup, that is oscillating up and down with a certain frequency, will react on this impulse with waves on her surface. The water oscillates up and down in the middle, like when a stone is thrown in a pool. Like there a ringwave will grow out, and is been followed by other circular waves, all with the same centre, so concentric.
When they meet the circular border (the cup), those waves will bounce back to the centre. Outgoing and backstreaming waves will influence each other, they interfere.
Then we turn the volume higher, and the water begins to dance, i bit like a hidden drumhead...
Vibrating of Circular Membranes
The vibration of a circular membrane , for exemple of a drum, bear resemblance to the general pattern in the watersurface (that forms a kind of membrane as well), namely one, two, three or more regular devided crests and troughs oscillating up and down.
On http://paws.kettering.edu/~drussell/Demos/MembraneCircle/Circle.html you can find an animation. And on wikipedia ,you can also see such a drumhead in oscillation.
Compare it with the film bellow or with this film of a water surface oscillating.
Watersoundimages can not simply be reduced to this because of several reasons:
- A drum-membrane has a fixed boundary, while our waterdisc can glide free up and down the border of the cup, and that linear waterboundary will moreover wave in itself. (film…)
- This watermembrane is much more flexible then a drummembrane, and can transform in very small details, small (regular) ripples, which travel arround over the global membrane, and superpose with each other. Their interference tops reflect the light to the camera.
The regular devision into 2, 3, 4, 5 sectors is probable caused by the global vibration like our drumhead.
- So, unlike in a drummembrane, inside this general oscillation appear smaller patterns and details, moving over the surface, inside the general devisions. The whole figure can slowly or fast rotate as a whole, sometimes alternating left and right.
- The watermembrane is “glued” on the watermass, which give other effects to the transformations of the surface then the air in a drum.
- In a watersoundimage we generate a continues, regular impuls, the watermovements organise themselves into a regular pattern, even more time-changes appear in a metamorphosis that maintains regularity!
A drop of water (or mercury) that is brought into vibration, also will show spherical harmonic forms and formchanges. How should react a balloon or a soapbubble?
When we put a light right above the centre of our cup, and look to it or film it perpendicular, we see the watersurface being devided in a regular way by several radials: 2, 3, 4, 5, 6, 7, and so on. Like when you slice a (round) pizza in equal pieces. Spontaneously you start counting. The midpoint-angles between the radials are equal.
This partition in equal sectors is almost the only thing that you can see with the naked ey, because everything happens so fast.
The rest of the structures can only be seen clearly by photographing them, the changes by filming them.
On such a foto you will see that inside a circle-sector all kind of patterns appear, and what is more, in all the sectors the same figure.
Those patterns are the result of interfering ripples, little waves that start from borders and curved crests, and travel throughout the undulating water-surface. You can observe this on the 3D-film above. Apparently they too are very regular, because the resulting patterns are equal and symmetric in all the sectors. The meeting (interference) of several curved ripples results sometimes even in straight lines! Wonderful, isn't it?
Hans Jenny, inventor and investigator of this wave-phenomenon in water described it as
a three-unity:
the periodic, pulsating VIBRATION generates the two poles of
FORM (figures, patterns, images, structure) and
MOTION (dynamics,streaming, processes)
Those images and their movements will be described in a geometrical way on the next page .
