Why Flour Sticks but Rice Falls Straight Through – The Science of Sifting #teamwater

When particulate materials such as rice or whole grains are passed through a sieve, their relatively large mass and smooth surface texture enable gravitational forces to dominate over any weak adhesive interactions with the mesh.

In contrast, flour consists of fine particles with a low mass-to-surface-area ratio. The resulting high specific surface area increases the relative significance of surface forces, including cohesion between particles and electrostatic adhesion to the sieve wires. These forces inhibit free flow, causing flour to aggregate and remain suspended in the mesh until agitation (like tapping or shaking) reduces these interactions and allows the particles to pass through.

#science #learning #physics #explained