Antlion larvae catch prey by digging conical pits in sand. The steep walls of the trap are near the angle of repose, the largest angle a granular material can maintain Keep reading
Tag: sand
Sandy Wrinkles
Water flowing back and forth over sand quickly forms a field of dune-like wrinkles. On the upstream side, the flow is a little faster, and it picks up grains of Keep reading
Turning Sand Into a Fluid
Pumping air through a bed of sand can make the grains behave just like a liquid. This process is called fluidization. Air introduced at the bottom of the bed forces Keep reading
Surge Flows
Sandy beaches can be a great place to play with neat flows. In a recent video, Frank Howarth describes playing with beach rivers on the Oregon coast and observing a Keep reading
Sand Dunes
Sand dunes form with a gentle incline facing the wind and a steeper slip face pointing away from the wind. Most slip faces are angled at about 30 to 34 Keep reading
Swimming Through Sand
Shovel-nosed snakes and sandfish lizards both swim through granular materials like sand. Researchers at Georgia Tech used x-rays to observe their subsurface motions. Despite their different shapes, the long, slender snake and the shorter, wider lizard both move Keep reading
Dancing Sands
Here a collection of dry grains are vertically vibrated, creating a series of standing waves on the surface of the sand. The shapes of these Faraday waves are dependent upon Keep reading
Barchan Dunes
The winds of Mars create sand dunes that seem to flow like a liquid across the planet’s surface. Here the wind blows from right to left around the flat top Keep reading
Granular Eruptions
Granular flows, which are made up of loose particles like sand, often display remarkably fluid-like behavior. Here researchers explore the behavior of granular flows when a solid impacts them at Keep reading
Singing Dunes
Some sand dunes can “sing”, but not because of the wind! When loose sand slides down over harder, packed sand, a standing wave is formed, causing the entire surface of Keep reading