A simple demonstration of granular phases

Steel spheres move on a plate. The "thermostat " is a vibrating wall, following a sine law with frequency 20 Hz . Weak gravity (the plate has a small angle of inclination) draws the spheres toward the vibrating wall. In 5 minutes, slowly increasing the amplitude, the many "phases" of a granular material are explored, from an almost perfect crystal, through several liquid/turbulent/convective regimes, up to a gas-solid coexistence. (This prototype has been realized by Franco Bagnoli and Alessio Guarino at the Dipartimento di Energetica, Firenze)

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  Education

[GranularChaos]

Which model? This is an experiment, there is no model (unfortunately)

[krlsjke]

beautiful demonstration and excellent commentary!

[ActiveStorage]

is it possible to use this model to explain cavitation?

[ActiveStorage]

Yeah i absolutely agree. Also every vibrating object has a specific "geometry" or "trajectory" of vibration. Understanding the "trajectories" is the key.  For example strings dont vibrate back in forth. They move in a circle, or in a elipse or in a number "8" pattern instead of just plain "up" and "down". Same for atoms.

[Rodion Telyatnik]

Cool! I mostly liked concentation "jump" between thermostat and granular phase, which is increasing with temperature (I guess an analogy to Lengmuire or Knudsen jump of temperature and concentration at the distance order of mean free path from the boundary)

This model of hard spheres with the gravity instead of attractive potential - how it's real ?=)

[Bassotronics]

Its like all susbtances that govern the universe are caused by vabrations. Depending on the vibration of molecules is how they attract or repel to create all the matter we know. Life is music. So vibrating string theory can be very likely to be true!