Light particles in water

Frequency=5 Hz with a backward initial disturbance. To see a movie clip of this pattern formation, click here.

Frequency =5 Hz with a forward initial disturbance. To see a movie clip of this pattern formation, click here.

Frequency =8 Hz. To see a movie clip of this pattern formation, click here.

Slightly heavier-than-water particles in water.
Frequency = 8 Hz. The following sequence of pictures discribe that the pattern changes with time.
To see a movie clip of this process, click here

Elapsed time: 0 second	Elapsed time: 4 seconds	Elapsed time: 8 seconds
Elapsed time: 12 seconds	Elapsed time: 12 seconds	Elapsed time: 16 seconds
Elapsed time: 20 seconds	Elapsed time: 24 seconds	Elapsed time: 28 seconds
Elapsed time: 32 seconds	Elapsed time: 36 seconds	Elapsed time: 40 seconds
Elapsed time: 44 second