Watch sand defy gravity and stream uphill due to “adverse friction”

There’s not often time to put in writing about each cool science-y story that comes our means. So this 12 months, we’re as soon as once more working a particular Twelve Days of Christmas collection of posts, highlighting one science story that fell by the cracks in 2023, every day from December 25 by January 5. In the present day: how making use of magnetic forces to particular person “micro-roller” particles spurs collective movement, producing some fairly counter-intuitive outcomes.

Engineering researchers at Lehigh University have discovered that sometimes sand can actually flow uphill.

Engineering researchers at Lehigh College have found that generally sand can really stream uphill. (credit score: Lehigh College)

We intuitively perceive that the sand pouring by an hourglass, for instance, varieties a neat roughly pyramid-shaped pile on the backside, by which the grains close to the floor stream over an underlying base of stationary particles. Avalanches and sand dunes exhibit related dynamics. However scientists at Lehigh College in Pennsylvania have found that making use of a magnetic torque can really trigger sand-like particles to collectively stream uphill in seeming defiance of gravity, in accordance with a September paper revealed within the journal Nature Communications.

Sand is fairly fascinating stuff from a physics standpoint. It is an instance of a granular materials, because it acts each like a liquid and a stable. Dry sand collected in a bucket pours like a fluid, but it may possibly help the burden of a rock positioned on prime of it, like a stable, regardless that the rock is technically denser than the sand. So sand defies all these tidy equations describing numerous phases of matter, and the transition from flowing “liquid” to a inflexible “stable” occurs fairly quickly. It is as if the grains act as people within the fluid type, however are able to all of a sudden banding collectively when solidarity is required, reaching a bizarre form of “energy in numbers” impact.

Learn eight remaining paragraphs | Feedback

Leave a Reply

Your email address will not be published. Required fields are marked *