https://johncarlosbaez.wordpress.com/2021/03/24/the-joy-of-condensed-matter/

Lamentations regarding the lack of low-hanging fruit in the sciences are pretty common nowadays. A genre of response to this is something like “Actually, this field is exciting! Lot’s to discover.” This is an entry in that genre.

mystery

We don’t know anything about wet, stable granules, nor do we know anything about kinda wet, kinda stable granules.

It also appears to be a field where practice (in the sense of, say, technical, industrial, and engineering concerns) has possibly outpaced theory (in the sense of, say, academic concerns). Quoting Mehta:

Powders have been studied extensively by engineers, so that there exists in fields such as chemical engineering a body of knowledge on particulate media that most physicists are simply unaware of. This unawareness leads to a recurrent tendency to reinvent wheels, but to reinvent them badly, as microscopic theories are put forward for “sandpiles” without any effort to make contact with well- established macroscopic results known to engineers.

There’s a sort of field-anthropological excitement inherent in digging into some community of practice that has had to solve real problems and find gems of understanding amid the dust of daily getting-it-done.

This sort of matter is not particularly exotic and is available to all of us to mess around with. Very fun.

Granular mechanics ref dump