Topic
Granular matter research, explained
5 open-access granular matter studies, each with a flashcard deck and a quiz.
- How solid is the surface of asteroid Bennu?
When NASA's OSIRIS-REx touched asteroid Bennu, its sampler sank easily into rubble that was loosely packed and barely stuck together, more like a ball pit than solid ground.
- Can jammed magnetic particle pillars remember past fields?
Magnetic fields pull nickel microparticles into conducting pillars that partly stay jammed when the field is removed, so the electrical current remembers how strongly and how quickly the field was changed.
- Can simple physics predict fast motion through sand?
A sand model with only constant friction, plus ordinary inertia, predicts how wheels, dragged plates and running legs behave in sand even at high speeds.
- Do living and nonliving packings differ in their neighbour topology?
Counting how neighbouring points connect in 3D is enough to tell most living tissues apart from nonliving packings like granular piles and foams.
- How do force chains in flowing sand become rigid?
In slowly sheared granular material, the network of strong contact forces becomes connected in exactly the way predicted by rigidity percolation theory, but faster flow changes the critical behaviour.