The Dynamics of Fine Powders
Rietema, K.
flour, potato starch, cracking catalyst, sand, and gravel, one will probably agree that the first four materials definitely are powders and the last one certainly is not. Whether one would call sand a powder probably depends on the partiele size and on personal Vlews. When the astronaut Neil Armstrong returned to the Earth from his trip on the surface of the Moon, he stated: 'The surface is fine and powdery. I can kick it up loosely with my to...