The ‘magic sand’ might assist us perceive the physics of granular matter
Sand is an enchanting materials. It could actually circulate and be poured like a liquid, however retains many properties of solids, clogging pipes or forming sand dunes. The conduct of collections of small particles like sand is called granular physics, and is an especially vital space for dealing with and transporting the big selection of granular supplies like grains, rice, powders and huge portions of sand used within the building trade.
A key conundrum on this department of physics is the variety of individuals concerned. The grains work together by way of easy Newtonian mechanics, however since so many particles work together directly, there may be an rising complexity in circulate conduct that can’t but be defined by easy equations. Scientists are subsequently trying not just for higher theoretical fashions to clarify granular conduct, but additionally for sensible ‘mannequin techniques’ that may be manipulated and adjusted within the laboratory to supply perception into how the microscopic construction of granular supplies provides rise to their outcomes. macroscopic properties.
A crew led by Assistant Professor Marie Tani and Professor Rei Kurita of Tokyo Metropolitan College investigated the properties of mixtures of silicone-coated “magic sand”, a well-liked youngsters’s toy, and regular sand. It was discovered that the silicone coated sand particles interacted solely with one another and never with different sand particles. The crew discovered that including silicone-coated sand past a sure threshold resulted in an abrupt change in grouping and stiffness, a possible strategy to modify the circulate of granular supplies for trade.
Researchers have studied what occurs to sand when it’s moist. It’s well-known that seaside sand, for instance, behaves fully otherwise; sandcastles are troublesome to construct when the sand is dry. This conduct is basically because of the formation of liquid “bridges” between particles, referred to as capillary bridges, strongly binding the grains collectively to kind load-bearing constructions. Nonetheless, homogeneous moist sand is notoriously troublesome to arrange within the laboratory; it’s troublesome to combine evenly and dries in a short time.
To beat this drawback, the researchers used “magic sand”, hydrophobic sand particles coated with silicone oil, generally obtainable in youngsters’s toys. The crew discovered that not solely do the grains of “magic sand” entice one another strongly by way of skinny strands of oil, however that it doesn’t work together with regular sand, merely bumping into it like dry grains. By mixing “magic sand” and regular sand in numerous proportions, the crew might freely examine the conduct of moist sand all the way down to the smallest liquid fractions, the place only some grains are linked by way of capillary bridges.
Utilizing three impartial strategies involving sieving, density measurement, and the formation of steady sand mounds, they discovered that the mechanical properties of the combination change dramatically when the fraction of magic sand to regular sand exceeds 20%. This dovetailed with the findings of percolation principle, which governs how the connections between particles develop in house with none breakage, leaving the sand combination to behave in a way more stable method and stand up to its personal weight. This conduct is understood for polymer gels and permits to unify the theoretical approaches utilized to fully totally different supplies.
The crew’s blends additionally exhibit simply modifiable mechanical properties. Importantly, the tactic affords a handy, correct, and informative new strategy to discover granular physics and will grow to be the brand new default technique for scientists in future investigations.
The place does the sand come from on Mars?
Marie Tani et al, Transition conduct in silicone coated sand mixtures, Journal of the Bodily Society of Japan (2021). DOI: 10.7566 / JPSJ.90.033801
Offered by Tokyo Metropolitan College
Quote: ‘Magic sand’ might assist us perceive the physics of granular matter (2021, March 8) retrieved March 9, 2021 from https://phys.org/information/2021-03-magic-sand-physics-granular. html
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